TSC2005_07 [BB]
1.6V to 3.6V, 12-Bit, Nanopower, 4-Wire TOUCH SCREEN CONTROLLER with SPI⑩ Interface; 1.6V至3.6V ， 12位，纳安级功耗， 4线触摸屏控制器， SPI⑩接口
| 型号： | TSC2005_07 |
| 厂家： | 
BURR-BROWN CORPORATION |
| 描述： | 1.6V to 3.6V, 12-Bit, Nanopower, 4-Wire TOUCH SCREEN CONTROLLER with SPI⑩ Interface |
| 文件： | 总44页 (文件大小：769K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
B
u
r
r
Ć
B
r
o
w
n
P
r
o
d
u
c
t
s
TSC2005
f
r
o
m
T
e
x
a
s
I
n
s
t
r
u
m
e
n
t
s
SBAS379A–DECEMBER 2006–REVISED MAY 2007
1.6V to 3.6V, 12-Bit, Nanopower, 4-Wire
TOUCH SCREEN CONTROLLER with SPI™ Interface
FEATURES
APPLICATIONS
•
•
•
•
•
•
Personal Digital Assistants
Cellular Phones
Portable Instruments
Point-of-Sale Terminals
MP3 Players, Pagers
Multiscreen Touch Control
•
•
•
•
•
•
•
4-Wire Touch Screen Interface
Ratiometric Conversion
Single 1.6V to 3.6V Supply
Preprocessing to Reduce Bus Activity
High-Speed SPI-Compatible Interface
Internal Detection of Screen Touch
Register-Based Programmable:
DESCRIPTION
–
–
–
10-Bit or 12-Bit Resolution
Sampling Rates
The TSC2005 is a very low-power touch screen
controller designed to work with power-sensitive,
handheld applications that are based on an
advanced low-voltage processor. It works with a
supply voltage as low as 1.6V, which can be
supplied by a single-cell battery. It contains a
complete, ultra-low power, 12-bit, analog-to-digital
(A/D) resistive touch screen converter, including
drivers and the control logic to measure touch
pressure.
System Timing
•
•
•
•
On-Chip Temperature Measurement
Touch Pressure Measurement
Auto Power-Down Control
Low Power:
–
–
–
800µW at 1.8V, 50SSPS
600µW at 1.6V, 50SSPS
In addition to these standard features, the TSC2005
offers preprocessing of the touch screen
measurements to reduce bus loading, thus reducing
the consumption of host processor resources that
can then be redirected to more critical functions.
75µW at 1.6V, 8.2kSPS Eq. Rate
•
Enhanced ESD Protection:
–
–
–
–
±6kV HBM
±1kV CDM
The TSC2005 supports an SPI-compatible serial bus
up to 25MHz. It offers programmable resolution of 10
or 12 bits to accommodate different screen sizes and
performance needs.
±25kV Air Gap Discharge
±12kV Contact Discharge
•
2.5 x 3 WCSP-18 Package
U.S. Patent NO. 6246394; other patents pending.
The TSC2005 is available in a miniature 18-lead,
5 x 6 array, 2.608 x 3.108 mm wafer chip-scale
package (WCSP). The device is characterized for the
–40°C to +85°C industrial temperature range.
PENIRQ
PINTDAV
DAV
VREF
X+
Touch
X-
CS
Screen
Drivers
Y+
SAR
ADC
SPI
SCLK
Interface
Mux
Y-
Serial
Interface
SDI
and
TEMP
Control
RESET
SDO
AUX
Internal
Clock
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
SPI is a trademark of Motorola, Inc.
All other trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2006–2007, Texas Instruments Incorporated
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be
more susceptible to damage because very small parametric changes could cause the device not to meet its published
specifications.
ORDERING INFORMATION(1)
TYPICAL
INTEGRAL
LINEARITY
(LSB)
TYPICAL
GAIN
ERROR
(LSB)
NO MISSING
CODES
RESOLUTION PACKAGE
SPECIFIED
TEMPERATURE PACKAGE
TRANSPORT
MEDIA,
QUANTITY
PACKAGE
DESIGNATOR
ORDERING
NUMBER
PRODUCT
(BITS)
TYPE
RANGE
MARKING
Small Tape
and Reel, 250
18-Pin,
5 x 6 Matrix,
2.5 x 3
TSC2005IYZLT
TSC2005IYZLR
TSC2005
±1.5
– 0.2/+4.4
11
YZL
–40°C to +85°C
TSC2005I
Tape and
Reel, 3000
WCSP
(1) For the most current package and ordering information, see the Package Option Addendum located at the end of this data sheet, or see
the TI website at www.ti.com.
ABSOLUTE MAXIMUM RATINGS(1)
Over operating free-air temperature range (unless otherwise noted)
TSC2005
–0.4 to SNSVDD + 0.1
–0.4 to SNSVDD + 0.1
–0.3 to 5
UNIT
V
Analog input X+, Y+, AUX to SNSGND
Analog input X–, Y– to SNSGND
SNSVDD to SNSGND
V
V
Voltage range
SNSVDD to AGND
–0.3 to 5
V
I/OVDD to DGND
–0.3 to 5
V
SNSVDD to I/OVDD
–2.40 to +0.3
–0.3 to I/OVDD + 0.3
–0.3 to I/OVDD + 0.3
(TJ Max - TA)/θJA
113
V
Digital input voltage to DGND
Digital output voltage to DGND
Power dissipation
V
V
WCSP package
Low-K
WCSP package
Thermal impedance, θJA
°C/W
High-K
62
Operating free-air temperature range, TA
Storage temperature range, TSTG
Junction temperature, TJ Max
–40 to +85
–65 to +150
+150
°C
°C
°C
°C
°C
kV
kV
Vapor phase (60 sec)
Infrared (15 sec)
X+, X–, Y+, Y–
+215
Lead temperature
+220
IEC contact discharge(2)
IEC air discharge(2)
±12
X+, X–, Y+, Y–
±25
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings
only, and functional operation of the device at these or any other conditions beyond those indicated is not implied. Exposure to
absolute-maximum rated conditions for extended periods may affect device reliability.
(2) Test method based on IEC standard 61000-4-2. Contact Texas Instruments for test details.
2
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
ELECTRICAL CHARACTERISTICS
At TA = –40°C to +85°C, SNSVDD = VREF = +1.6V to +3.6V, I/OVDD = +1.2V to +3.6V, unless otherwise noted.
TSC2005
PARAMETER
TEST CONDITIONS
MIN
0
TYP
MAX
VREF
+1
UNIT
AUXILIARY ANALOG INPUT
Input voltage range
Input capacitance
Input leakage current
A/D CONVERTER
Resolution
V
12
pF
µA
–1
Programmable: 10 or 12 bits
12
Bits
Bits
No missing codes
Integral linearity
12-bit resolution
11
±1.5
–0.8 to +0.3
+3.2 to +8.9
–0.2 to 0
LSB(1)
LSB
LSB
LSB
LSB
SNSVDD = 1.6V, VREF = 1.6V
SNSVDD = 3.0V, VREF = 2.5V
SNSVDD = 1.6V, VREF = 1.6V
SNSVDD = 3.0V, VREF = 2.5V
Offset error
Gain error
+3.8 to +4.4
REFERENCE INPUT
VREF range
1.6
SNSVDD
V
Non-cont. AUX mode, SNSVDD = 3V, VREF = 2.5V,
TA = +25°C, fADC = 2MHz, fSCLK = 10MHz
VREF input current drain
5.6
1
µA
GΩ
Input impedance
A/D converter not converting
TOUCH SENSORS
PENIRQ Pull-Up Resistor, RIRQ
TA = +25°C, SNSVDD = 3V, VREF = 2.5V
51
6
kΩ
Ω
Y+, X+
Switch
On-Resistance
Y–, X–
5
Ω
Switch drivers drive current(2)
TEMPERATURE MEASUREMENT
Temperature range
100ms duration
50
mA
–40
+85
°C
Differential method(3), SNSVDD = 3V VREF = 2.5V
TEMP1(4), SNSVDD = 3V VREF = 2.5V
1.6
0.3
±2
°C/LSB
°C/LSB
°C/LSB
°C/LSB
Resolution
Differential method(3), SNSVDD = 3V VREF = 2.5V
TEMP1(4), SNSVDD = 3V VREF = 2.5V
Accuracy
±3
INTERNAL OSCILLATOR
Clock frequency, fOSC
SNSVDD = 1.6V
SNSVDD = 3.0V
SNSVDD = 1.6V
SNSVDD = 3.0V
3.6
3.8
MHz
MHz
%/°C
%/°C
0.0056
0.012
Frequency drift
DIGITAL INPUT/OUTPUT
Logic family
CMOS
1.2V ≤ I/OVDD < 1.6V
1.6V ≤ I/OVDD ≤ 3.6V
1.2V ≤ I/OVDD < 1.6V
1.6V ≤ I/OVDD ≤ 3.6V
SCLK pin or CS pin
0.7 × I/OVDD
0.7 × I/OVDD
–0.3
I/OVDD + 0.3
V
V
VIH
VIL
I/OVDD + 0.3
0.2 × I/OVDD
V
–0.3
0.3 × I/OVDD
V
IIL
Logic level
CIN
–1
1
10
µA
pF
V
VOH
IOH = 2 TTL loads
IOL = 2 TTL loads
Floating output
Floating output
I/OVDD – 0.2
I/OVDD
0.2
VOL
ILEAK
0
V
–1
1
µA
pF
COUT
10
Data format
Straight Binary
(1) LSB means Least Significant Bit. With VREF = +2.5V, one LSB is 610µV.
(2) Assured by design, but not tested. Exceeding 50mA source current may result in device degradation.
(3) Difference between TEMP1 and TEMP2 measurement; no calibration necessary.
(4) Temperature drift is –2.1mV/°C.
3
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
ELECTRICAL CHARACTERISTICS (continued)
At TA = –40°C to +85°C, SNSVDD = VREF = +1.6V to +3.6V, I/OVDD = +1.2V to +3.6V, unless otherwise noted.
TSC2005
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
POWER-SUPPLY REQUIREMENTS
Power-supply voltage
SNSVDD(5)
Specified performance
1.6
1.2
3.6
V
V
I/OVDD(6)
SNSVDD
With filter, M = 15, W = 7, PSM = 1, C[3:0] = (0,0,0,0),
RM = 1, CL[1:0] = (0,1), BTD[2:0] = (1,0,1), 50SSPS,
MAVEX = MAVEY = MAVEZ = 1, SNSVDD = I/OVDD =
REF = 1.6V, fADC = 2MHz, fSCLK = 10MHz, sensor drivers
supply included
383
361
µA
µA
Bypass filter, M = W = 1, PSM = 1, C[3:0] = (0,0,0,0),
RM = 1, CL[1:0] = (0,1), MAVEX = MAVEY = MAVEZ =
1, SNSVDD = I/OVDD = REF = 1.6V, fADC = 2MHz, fSCLK
= 10MHz, sensor drivers supply included
Bypass filter, M = W = 1, C[3:0] = (0,1,0,1), RM = 1,
CL[1:0] = (0,1), non-cont AUX mode, SNSVDD =
I/OVDD = REF = 1.6V, fADC = 2MHz, fSCLK = 10MHz
481
943
µA
µA
Quiescent supply current(7)
Bypass filter, M = W = 1, C[3:0] = (0,1,0,1), RM = 1,
CL[1:0] = (0,1), non-cont AUX mode, SNSVDD = 3V,
I/OVDD = REF = 1.6V, fADC = 2MHz, fSCLK = 10MHz
With filter, M = 7, W = 3, C[3:0] = (0,1,0,1), RM = 1,
CL[1:0] = (0,1), MAVEAUX = 1, non-cont AUX mode,
SNSVDD = I/OVDD = REF = 1.6V, fADC = 2MHz, fSCLK
3.5MHz, full speed, (~13kSPS effective rate, 91kSPS
equivalent rate)
=
=
522
µA
With filter, M = 7, W = 3, C[3:0] = (0,1,0,1), RM = 1,
CL[1:0] = (0,1), MAVEAUX = 1, non-cont AUX mode,
SNSVDD = I/OVDD = REF = 1.6V, fADC = 2MHz, fSCLK
3.5MHz, reduced speed, (~1.17kSPS effective rate,
8.2kSPS equivalent rate)
47
0
µA
µA
Power down supply current
CS high, SCLK = 0
0.8
(5) TSC2005 functions down to 1.4V, typically.
(6) I/OVDD must be ≤ SNSVDD.
(7) Supply current from SNSVDD.
4
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
PIN CONFIGURATION
YZL PACKAGE
WCSP-18
(TOP VIEW, SOLDER BUMPS ON BOTTOM SIDE)
AGND
VREF SNSVDD
X+
NC
Y+
SUBGND
5
4
3
2
1
AUX
NC
NC
NC
X-
I/OVDD
DGND
NC
NC
Y-
NC
NC
NC
NC
SNSGND
SDI
SCLK
SDO
RESET PINTDAV
CS
F
A
B
C
D
E
Columns
(FRONT VIEW)
PIN ASSIGNMENTS
PIN
NO.
NAME
I/O
A/D DESCRIPTION
A1
A2
A3
A4
A5
B1
RESET
DGND
I
D
System reset. All register values reset to default value.
Digital ground
I/OVDD
AUX
Digital I/O interface voltage
Auxiliary channel input
I
A
D
AGND
Analog ground
PINTDAV
O
Interrupt output. Data available or PENIRQ depends on setting. Pin polarity with active low.
B2, B3,
B4, C2,
D2, E2,
E3, E4
NC
No connection.
B5
C1
VREF
SDI
I
I
A
D
External reference input
Serial data input. This input is the MOSI signal for the SPI interface protocol.
C3, C4,
D3, D4
NC
No connection. Sensitive area; avoid trace beneath. Some bumps on the WCSP may be depopulated.
C5
D1
D5
E1
E5
F1
F2
F3
F4
F5
SNSVDD
SCLK
X+
Power supply for sensor drivers and other analog blocks.
I
I
D
A
D
A
D
Serial clock input
X+ channel input
SDO
O
I
Serial data output. This output is the MISO for the SPI interface protocol.
Y+
Y+ channel input
CS
I
Chip select. This input is the slave select (SS) signal for the SPI interface protocol.
SNSGND
Y–
Sensor driver return
I
I
A
A
Y– channel input
X–
X– channel input
SUBGND
Substrate ground (for ESD current)
5
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
TIMING INFORMATION
The TSC2005 supports SPI programming in mode CPOL = 0 and CPHA = 0. The falling edge of SCLK is used
to change output (MISO) data and the rising edge is used to latch input (MOSI) data. Eight SCLKs are required
to complete the Byte 1 command cycle, and 24 SCLKs are required for the Byte 0 command cycle. CS can stay
low during the entire 24 SCLKs of a Byte 0 command cycle, or multiple mixed cycles of reading and writing of
bytes and register accesses, as long as the corresponding addresses are supplied.
CS (SS)
tC(SCLK)
tWH(SCLK)
tWH(CS)
tSU(SCLKF-CSR)
tSU(CSF-SCLK1R)
tF
tR
tWL(SCLK)
SCLK
tH(SCLKF-SDOVALID)
BIT 1
tDIS(CSR-SDOZ)
SDO (MISO)
MSB OUT
BIT 0
BIT 0
tD(CSF-SDOVALID)
tSU(SDI-SCLKR)
tH(SDI-SCLKR)
SDI (MOSI)
BIT 1
MSB IN
NOTE: CPOL = 0, CPHA = 0, Byte 0 cycle requires 24 SCLKs, and Byte 1 cycle requires 8 SCLKs.
Figure 1. Detailed I/O Timing
TIMING REQUIREMENTS(1)
All specifications typical at –40°C to +85°C, SNSVDD = I/OVDD = 1.6V, unless otherwise noted.
PARAMETER
Reset low time
TEST CONDITIONS
I/OVDD = SNSVDD ≥ 1.6V(2)
MIN
10
MAX
UNIT
µs
tWL(RESET)
tC(SCLK)
I/OVDD ≥ 1.6V and < 2.7V, 40% to 60% duty cycle
I/OVDD ≥ 2.7V and ≤ 3.6V, 40% to 60% duty cycle
I/OVDD ≥ 1.6V and < 2.7V, 10pF load
100
40
ns
SPI serial clock cycle time
SPI serial clock frequency
ns
10
25
MHz
MHz
ns
fSCLK
I/OVDD ≥ 2.7V and ≤ 3.6V, 10pF load
tWH(SCLK)
SPI serial clock high time
SPI serial clock low time
Enable lead time
0.4 × tC(SCLK)
0.4 × tC(SCLK)
30
0.6 × tC(SCLK)
0.6 × tC(SCLK)
tWL(SCLK)
ns
tSU(CSF-SCLK1R)
tD(CSF-SDOVALID)
tH(SCLKF-SDOVALID)
tWH(CS)
ns
Slave access time
MISO data hold time
Sequential transfer delay
MOSI data setup time
MOSI data hold time
Slave MISO disable time
Enable lag time
15
13
ns
6
15
4
ns
ns
tSU(SDI-SCLKR)
tH(SDI-SCLKR)
tDIS(CSR-SDOZ)
tSU(SCLKF-CSR)
tR
ns
4
ns
15
ns
30
ns
Rise time
SNSVDD = I/OVDD = 3V, fSCLK = 25MHz
SNSVDD = I/OVDD = 3V, fSCLK = 25MHz
3
3
ns
tF
Fall time
ns
(1) All input signals are specified with tR = tF = 5ns (10% to 90% of I/OVDD) and timed from a voltage level of (VIL + VIH)/2.
(2) Refer to Figure 30.
6
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
TYPICAL CHARACTERISTICS
At TA = –40°C to +85°C, SNSVDD = VREF = +1.6V to +3.6V, I/OVDD = +1.2V to +3.6V, fADC = fOSC/2, fSCLK = 10MHz, 12-bit
mode, and non-continuous AUX measurement, unless otherwise noted.
SUPPLY CURRENT
vs TEMPERATURE
SUPPLY CURRENT
vs TEMPERATURE
1100
1050
1000
950
40
35
30
25
20
15
I/OVDD = SNSVDD = 3V
VREF = 2.5V
I/OVDD = SNSVDD = 3V
VREF = 2.5V
900
850
800
750
-40
-20
0
20
40
60
80
100
-40
-20
0
20
40
60
80
100
Temperature (°C)
Temperature (°C)
Figure 2.
Figure 3.
POWER-DOWN SUPPLY CURRENT
vs TEMPERATURE
SUPPLY CURRENT
vs SUPPLY VOLTAGE
100
80
60
40
20
0
1.50
1.25
1.00
0.75
0.50
0.25
0
TA = +25°C
I/OVDD = VREF = 1.6V
SNSVDD = 3.0V
SNSVDD = 3.6V
fADC = 1MHz
fADC = 2MHz
SNSVDD = 1.6V
I/OVDD = SNSVDD
VREF = 1.6V
-40
-20
0
20
40
60
80
100
1.6
2.0
2.4
2.8
3.2
3.6
SNSVDD (V)
Temperature (°C)
Figure 4.
Figure 5.
SUPPLY CURRENT
vs SUPPLY VOLTAGE
CHANGE IN GAIN
vs TEMPERATURE
50
45
40
35
30
25
20
15
10
5
0.6
0.4
I/OVDD = SNSVDD = 3V
VREF = 2.5V
TA = +25°C
SNSVDD = 3.6V
VREF = 1.6V
fADC = 2MHz
0.2
0
fADC = 1MHz
-0.2
-0.4
-0.6
0
1.6
2.0
2.4
2.8
3.2
3.6
-40
-20
0
20
40
60
80
100
I/OVDD (V)
Temperature (°C)
Figure 6.
Figure 7.
7
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
TYPICAL CHARACTERISTICS (continued)
At TA = –40°C to +85°C, SNSVDD = VREF = +1.6V to +3.6V, I/OVDD = +1.2V to +3.6V, fADC = fOSC/2, fSCLK = 10MHz, 12-bit
mode, and non-continuous AUX measurement, unless otherwise noted.
CHANGE IN OFFSET
vs TEMPERATURE
REFERENCE INPUT CURRENT
vs TEMPERATURE
6
4
8
7
6
5
4
I/OVDD = SNSVDD = 3V
VREF = 2.5V
I/OVDD = SNSVDD = 3V
VREF = 2.5V
2
0
-2
-4
-6
-40
-20
0
20
40
60
80
100
-40
-20
0
20
40
60
80
100
Temperature (°C)
Temperature (°C)
Figure 8.
Figure 9.
SWITCH ON-RESISTANCE
vs SUPPLY VOLTAGE
SWITCH ON-RESISTANCE
vs TEMPERATURE
8
7
6
5
4
3
7
Y+
X+
Y+
6
5
4
3
2
1
X+
X-
Y-
X-
Y-
X+, Y+: SNSVDD to Pin
X+, Y+: SNSVDD = 3V to Pin
X-, Y-: Pin to GND
X-, Y-: Pin to GND
1.6
2.0
2.4
2.8
3.2
3.6
-40
-20
0
20
40
60
80
100
SNSVDD (V)
Temperature (°C)
Figure 10.
Figure 11.
SWITCH ON-RESISTANCE
vs TEMPERATURE
TEMP DIODE VOLTAGE
vs TEMPERATURE
9
8
7
6
5
4
3
2
850
800
750
700
650
600
550
500
450
400
Measurement Includes
A/D Converter Offset
and Gain Errors
Y+
95.2mV
X+
TEMP2
X-
Y-
TEMP1
138.1mV
I/OVDD = SNSVDD = 3V
VREF = 2.5V
X+, Y+: SNSVDD = 1.8V to Pin
X-, Y-: Pin to GND
-40
-20
0
20
40
60
80
100
-40
-20
0
20
40
60
80
100
Temperature (°C)
Temperature (°C)
Figure 12.
Figure 13.
8
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
TYPICAL CHARACTERISTICS (continued)
At TA = –40°C to +85°C, SNSVDD = VREF = +1.6V to +3.6V, I/OVDD = +1.2V to +3.6V, fADC = fOSC/2, fSCLK = 10MHz, 12-bit
mode, and non-continuous AUX measurement, unless otherwise noted.
TEMP1 DIODE VOLTAGE
vs SUPPLY VOLTAGE
TEMP2 DIODE VOLTAGE
vs SUPPLY VOLTAGE
588
586
584
582
580
578
576
574
704
702
700
698
696
694
692
690
Measurement Includes
A/D Converter Offset
and Gain Errors
Measurement Includes
A/D Converter Offset
and Gain Errors
TA = +25°C
TA = +25°C
I/OVDD = SNSVDD
VREF = 1.6V
I/OVDD = SNSVDD
VREF = 1.6V
1.6
2.0
2.4
2.8
3.2
3.6
1.6
2.0
2.4
2.8
3.2
3.6
SNSVDD (V)
SNSVDD (V)
Figure 14.
Figure 15.
SUPPLY CURRENT
vs SUPPLY VOLTAGE
INTERNAL OSCILLATOR CLOCK FREQUENCY
vs TEMPERATURE
1.2
1.0
0.8
0.6
0.4
0.2
0
3.70
3.65
3.60
3.55
3.50
TA = +25°C
SNSVDD = 1.6V
I/OVDD = SNSVDD
VREF = 1.6V
tPVS, tPRE, tSNS = Default Values
M = 15, W = 7
M = 1, W = 1
TSC-Initiated Mode Scan X, Y, Z at 50SSPS
Touch Sensor modeled by: 2kW for X-Plane
2kW for Y-Plane
1kW for Z (Touch Resistance)
1.6
2.0
2.4
2.8 3.2
3.6
-40
-20
0
20
40
60
80
100
SNSVDD (V)
Temperature (°C)
Figure 16.
Figure 17.
INTERNAL OSCILLATOR CLOCK FREQUENCY
vs TEMPERATURE
3.95
SNSVDD = 3.0V
3.90
3.85
3.80
3.75
-40
-20
0
20
40
60
80
100
Temperature (°C)
Figure 18.
9
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
OVERVIEW
The TSC2005 is an analog interface circuit for a human interface touch screen device. A register-based
architecture eases integration with microprocessor-based systems through a standard SPI bus. All peripheral
functions are controlled through the registers and onboard state machines. The TSC2005 features include:
•
•
•
•
•
•
Very low-power touch screen controller
Very small onboard footprint
Relieves host from tedious routine tasks by flexible preprocessing, saving resources for more critical tasks
Ability to work on very low supply voltage
Minimal connection interface allows easiest isolation and reduces the number of dedicated I/O pins required
Miniature, yet complete; requires no external supporting component. (NOTE: Although the TSC2005 can use
an external reference, it is also possible to use SNSVDD as the reference.)
•
Enhanced ESD up to 6kV
The TSC2005 consists of the following blocks (refer to the block diagram on the front page):
•
•
•
•
•
•
Touch Screen Interface
Auxiliary Input (AUX)
Temperature Sensor
Acquisition Activity Preprocessing
Internal Conversion Clock
SPI Interface
Communication with the TSC2005 is done via an SPI serial interface. The TSC2005 is an SPI slave device;
therefore, data are shifted into or out of the TSC2005 under control of the host microprocessor, which also
provides the serial data clock.
Control of the TSC2005 and its functions is accomplished by writing to different registers in the TSC2005. A
simple serial command protocol, compatible with SPI, is used to address these registers.
The measurement result is placed in the TSC2005 registers and may be read by the host at any time. This
preprocessing frees up the host so that resources can be redirected for more critical tasks. Two optional signals
are also available from the TSC2005 to indicate that data is available for the host to read. PINTDAV is a
programmable interrupt/status output pin that can be programmed to indicate a pen-touch, data available, or the
combination of both. Figure 19 shows a typical application of the TSC2005.
1.6VDC
1mF
0.1mF
AGND
1mF
0.1mF
1mF
0.1mF
Host
DGND
Processor
SNSGND
PINTDAV
GPIO
GPIO
SDI
X+
Y+
X-
Y-
RESET
SDO
TSC2005
SCLK
SCLK
Touch
Screen
(PINTDAV is optional;
software implementation
polling of the Status
register is possible)
SDO
CS
Auxilary Input
AGND
Figure 19. Typical Circuit Configuration
10
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
OVERVIEW (continued)
TOUCH SCREEN OPERATION
A resistive touch screen operates by applying a voltage across a resistor network and measuring the change in
resistance at a given point on the matrix where the screen is touched by an input (stylus, pen, or finger). The
change in the resistance ratio marks the location on the touch screen.
The TSC2005 supports the resistive 4-wire configurations, as shown in Figure 20. The circuit determines
location in two coordinate pair dimensions, although a third dimension can be added for measuring pressure.
4-WIRE TOUCH SCREEN COORDINATE PAIR MEASUREMENT
A 4-wire touch screen is typically constructed as shown in Figure 20. It consists of two transparent resistive
layers separated by insulating spacers.
Conductive Bar
Transparent Conductor (ITO)
Bottom Side
Y+
X+
Silver
Transparent
Conductor (ITO)
Top Side
Ink
X-
Y-
Insulating Material (Glass)
ITO = Indium Tin Oxide
Figure 20. 4-Wire Touch Screen Construction
The 4-wire touch screen panel works by applying a voltage across the vertical or horizontal resistive network.
The A/D converter converts the voltage measured at the point where the panel is touched. A measurement of
the Y position of the pointing device is made by connecting the X+ input to a data converter chip, turning on the
Y+ and Y– drivers, and digitizing the voltage seen at the X+ input. The voltage measured is determined by the
voltage divider developed at the point of touch. For this measurement, the horizontal panel resistance in the X+
lead does not affect the conversion because of the high input impedance of the A/D converter.
Voltage is then applied to the other axis, and the A/D converter converts the voltage representing the X position
on the screen. This process provides the X and Y coordinates to the associated processor.
Measuring touch pressure (Z) can also be done with the TSC2005. To determine pen or finger touch, the
pressure of the touch must be determined. Generally, it is not necessary to have very high performance for this
test; therefore, 10-bit resolution mode is recommended (however, data sheet calculations will be shown with the
12-bit resolution mode). There are several different ways of performing this measurement. The TSC2005
supports two methods. The first method requires knowing the X-plate resistance, the measurement of the
X-Position, and two additional cross panel measurements (Z2 and Z1) of the touch screen (see Figure 21).
Equation 1 calculates the touch resistance:
XPostition Z2
ǒ Ǔ
RTOUCH + RX−plate
@
* 1
4096
Z1
(1)
The second method requires knowing both the X-plate and Y-plate resistance, measurement of X-Position and
Y-Position, and Z1. Equation 2 also calculates the touch resistance:
RX−plate @ XPostition
YPosition
4096
4096
Z1
ǒ Ǔ ǒ1* Ǔ
RTOUCH
+
*1 *RY−plate @
4096
(2)
11
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
OVERVIEW (continued)
Measure X-Position
X+
Y+
Touch
X-Position
X-
Y-
Measure Z1-Position
Y+
X+
Touch
Z1-Position
X-
Y-
Y+
X+
Touch
Z2-Position
X-
Y-
Measure Z2-Position
Figure 21. Pressure Measurement
When the touch panel is pressed or touched and the drivers to the panel are turned on, the voltage across the
touch panel will often overshoot and then slowly settle down (decay) to a stable DC value. This effect is a result
of mechanical bouncing caused by vibration of the top layer sheet of the touch panel when the panel is pressed.
This settling time must be accounted for, or else the converted value will be in error. Therefore, a delay must be
introduced between the time the driver for a particular measurement is turned on, and the time a measurement
is made.
In some applications, external capacitors may be required across the touch screen for filtering noise picked up
by the touch screen (for example, noise generated by the LCD panel or back-light circuitry). The value of these
capacitors provides a low-pass filter to reduce the noise, but will cause an additional settling time requirement
when the panel is touched.
The TSC2005 offers several solutions to this problem. A programmable delay time is available that sets the
delay between turning the drivers on and making a conversion. This delay is referred to as the panel voltage
stabilization time, and is used in some of the TSC2005 modes. In other modes, the TSC2005 can be
commanded to turn on the drivers only without performing a conversion. Time can then be allowed before the
command is issued to perform a conversion.
The TSC2005 touch screen interface can measure position (X,Y) and pressure (Z). Determination of these
coordinates is possible under three different modes of the A/D converter:
•
•
•
TSMode1—conversion controlled by the TSC2005 initiated by TSC;
TSMode2—conversion controlled by the TSC2005 initiated by the host responding to the PENIRQ signal; or
TSMode3—conversion completely controlled by the host processor.
12
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
OVERVIEW (continued)
INTERNAL TEMPERATURE SENSOR
In some applications, such as battery recharging, an ambient temperature measurement is required. The
temperature measurement technique used in the TSC2005 relies on the characteristics of a semiconductor
junction operating at a fixed current level. The forward diode voltage (VBE) has a well-defined characteristic
versus temperature. The ambient temperature can be predicted in applications by knowing the +25°C value of
the VBE voltage and then monitoring the delta of that voltage as the temperature changes.
The TSC2005 offers two modes of temperature measurement. The first mode requires calibration at a known
temperature, but only requires a single reading to predict the ambient temperature. The TEMP1 diode, shown in
Figure 22, is used during this measurement cycle. This voltage is typically 580mV at +25°C with a 10µA current.
The absolute value of this diode voltage can vary by a few millivolts; the temperature coefficient (TC) of this
voltage is very consistent at –2.1mV/°C. During the final test of the end product, the diode voltage would be
stored at a known room temperature, in system memory, for calibration purposes by the user. The result is an
equivalent temperature measurement resolution of 0.3°C/LSB (1LSB = 610µV with VREF = 2.5V).
SNSVDD
+IN
Converter
-IN
AGND
Figure 22. Functional Block Diagram of Temperature Measurement Mode
The second mode does not require a test temperature calibration, but uses a two-measurement (differential)
method to eliminate the need for absolute temperature calibration and for achieving 2°C/LSB accuracy. This
mode requires a second conversion of the voltage across the TEMP2 diode with a resistance 80 times larger
than the TEMP1 diode. The voltage difference between the first (TEMP1) and second (TEMP2) conversion is
represented by:
kT
q
DV +
@ ln(N)
(3)
Where:
N = the resistance ratio = 80,
k = Boltzmann's constant = 1.3807 × 10–23 J/K (joules/kelvins).
q = the electron charge = 1.6022 × 10–19 C (coulombs).
T = the temperature in kelvins (K).
This method can provide much improved absolute temperature measurement, but a lower resolution of
1.6°C/LSB. The resulting equation to solve for T is:
q @ DV
k @ ln(N)
T +
(4)
Where:
∆V = VBE (TEMP2) – VBE(TEMP1) (in mV)
T = 2.648 ∆V (in K)
or T = 2.648 ∆V – 273 (in °C)
Temperature 1 and/or temperature 2 measurements have the same timing as Figure 38.
13
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
OVERVIEW (continued)
ANALOG-TO-DIGITAL CONVERTER
Figure 23 shows the analog inputs of the TSC2005. The analog inputs (X, Y, and Z touch panel coordinates,
chip temperature and auxiliary inputs) are provided via a multiplexer to the Successive Approximation Register
(SAR) Analog-to-Digital (A/D) converter. The A/D architecture is based on capacitive redistribution architecture,
which inherently includes a sample-and-hold function.
SNSVDD
VREF
PINTDAV
SNSVDD
Level Shift
RIRQ
51kW
Preprocessing
Data
Pen Touch
Available
Zone
Control
Logic
Detect
MAV
C3-C0
AGND
X+
X-
SNSVDD
Y+
+REF
+IN
Y-
Converter
-IN
-REF
SNSGND
AUX
AGND
Figure 23. Simplified Diagram of the Analog Input Section
A unique configuration of low on-resistance switches allows an unselected A/D converter input channel to
provide power and an accompanying pin to provide ground for driving the touch panel. By maintaining a
differential input to the converter and a differential reference input architecture, it is possible to negate errors
caused by the driver switch on-resistances.
The A/D converter is controlled by two A/D Converter Control registers. Several modes of operation are
possible, depending on the bits set in the control registers. Channel selection, scan operation, preprocessing,
resolution, and conversion rate may all be programmed through these registers. These modes are outlined in
the sections that follow for each type of analog input. The conversion results are stored in the appropriate result
register.
14
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
OVERVIEW (continued)
Data Format
The TSC2005 output data is in Straight Binary format as shown in Figure 24. This figure shows the ideal output
code for the given input voltage and does not include the effects of offset, gain, or noise.
(1)
FS = Full-Scale Voltage = VREF
1LSB = VREF(1)/4096
1LSB
11...111
11...110
11...101
00...010
00...001
00...000
0V
FS - 1LSB
Input Voltage(2) (V)
(1) Reference voltage at converter: +REF – (–REF). See Figure 23.
(2) Input voltage at converter, after multiplexer: +IN – (–IN). See Figure 23.
Figure 24. Ideal Input Voltages and Output Codes
Reference
The TSC2005 uses an external voltage reference that applied to the VREF pin. It is possible to use VDD as the
reference voltage because the upper reference voltage range is the same as the supply voltage range, .
Variable Resolution
The TSC2005 provides either 10-bit or 12-bit resolution for the A/D converter. Lower resolution is often practical
for measureing slow changing signals such as touch pressure. Performing the conversions at lower resolution
reduces the amount of time it takes for the A/D converter to complete its conversion process, which also lowers
power consumption.
Conversion Clock and Conversion Time
The TSC2005 contains an internal clock (oscillator) that drives the internal state machines that perform the
many functions of the part. This clock is divided down to provide a conversion clock for the A/D converter. The
division ratio for this clock is set in the A/D Converter Control register (see Table 15). The ability to change the
conversion clock rate allows the user to choose the optimal values for resolution, speed, and power dissipation.
If the 4MHz (oscillator) clock is used directly as the A/D converter clock (when CL[1:0] = (0,0)), the A/D
converter resolution is limited to 10-bits. Using higher resolutions at this speed does not result in more accurate
conversions. 12-bit resolution requires that CL[1:0] is set to (0,1) or (1,0).
Regardless of the conversion clock speed, the internal clock runs nominally at 3.8MHz at a 3V supply
(SNSVDD) and slows down to 3.6MHz at a 1.6V supply. The conversion time of the TSC2005 depends on
several functions. While the conversion clock speed plays an important role in the time it takes for a conversion
to complete, a certain number of internal clock cycles are needed for proper sampling of the signal. Moreover,
additional times (such as the panel voltage stabilization time), can add significantly to the time it takes to perform
a conversion. Conversion time can vary depending on the mode in which the TSC2005 is used. Throughout this
data sheet, internal and conversion clock cycles are used to describe the amount of time that many functions
take. These times must be taken into account when considering the total system design.
15
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
OVERVIEW (continued)
Touch Detect
PINTDAV can be programmed to generate an interrupt to the host. Figure 25 details an example for the
Y-position measurement. While in the power-down mode, the Y– driver is on and connected to GND. The
internal pen-touch signal depends on whether or not the X+ input is driven low. When the panel is touched, the
X+ input is pulled to ground through the touch screen and the internal pen-touch output is set to low because of
the detection on the current path through the panel to GND, which initiates an interrupt to the processor. During
the measurement cycles for X- and Y-Position, the X+ input is disconnected, which eliminates any leakage
current from the pull-up resistor to flow through the touch screen, thus causing no errors.
Analog VDD
Plane
SNSVDD
PINTDAV
SNSVDD
Level
Shifter
RIRQ
51kW
Y+
X+
Pen Touch
Data Available
Control
Logic
High when
the X+ or Y+
driver is on.
Sense
DGND
Y-
High when the X+ or Y+
driver is on, or when any
sensor connection/short
circuit tests are activated.
ON
Vias go to system analog ground plane.
SNSGND
AGND
Figure 25. Example of a Pen-Touch Induced Interrupt via the PINTDAV Pin
In modes where the TSC2005 must detect whether or not the screen is still being touched (for example, when
doing a pen-touch initiated X, Y, and Z conversion), the TSC2005 must reset the drivers so that the RIRQ resistor
is connected again. Because of the high value of this pull-up resistor, any capacitance on the touch screen
inputs will cause a long delay time, and may prevent the detection from occurring correctly. To prevent this
possible delay, the TSC2005 has a circuit that allows any screen capacitance to be precharged, so that the
pull-up resistor does not have to be the only source for the charging current. The time allowed for this
precharge, as well as the time needed to sense if the screen is still touched, can be set in the configuration
register.
This configuration underscores the need to use the minimum possible capacitor values on the touch screen
inputs. These capacitors may be needed to reduce noise, but too large a value will increase the needed
precharge and sense times, as well as the panel voltage stabilization time.
16
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
OVERVIEW (continued)
Preprocessing
The TSC2005 offers an array of powerful preprocessing operations that reduce unnecessary traffic on the bus
and reduce host processor loading. This reduction is especially critical for the serial interface, where limited
bandwidth is a tradeoff, keeping the connection lines to a minimum.
All data acquisition tasks are looking for specific data that meet certain criteria. Many of these tasks fall into a
predefined range, while other tasks may be looking for a value in a noisy environment. If these data are all to be
retrieved by host processor for processing, the limited bus bandwidth will be quickly saturated, along with the
host processor processing capability. In any case, the host processor must always be reserved for more critical
tasks, not for routine work.
The preprocessing unit consists of two main functions: the combined MAV filter (median value filter and
averaging filter), followed by the zone detection.
Preprocessing - Median Value Filter and Averaging Value Filter
The first preprocessing function, a combined MAV filter, can be operated independently as a median value filter
(MVF), an averaging value filter (AVF) and a combined filter (MAVF).
If the acquired signal source is noisy because of the digital switching circuit, it may be necessary to evaluate the
data without noise. In this case, the median value filter (MVF) operation helps to discard the noise. The array of
N converted results is first sorted. The return value is either the middle (median value) of an array of M
converted results, or the average value of a window size of W of converted results:
•
•
•
N = the total number of converted results used by the MAV filter
M = the median value filter size programmed
W = the averaging window size programmed
If M = 1, then N = W. A special case is W = 1, which means the MAVF is bypassed. Otherwise, if W > 1, only
averaging is performed on these converted results. In either case, the return value is the averaged value of
window size W of converted results. If M > 1 and W = 1, then N = M, meaning only the median value filter is
operating. The return value is the middle position converted result from the array of M converted results. If M > 1
and W > 1, then N = M. In this case, W < M. The return value is the averaged value of middle portion W of
converted results out of the array of M converted results. Since the value of W is an odd number in this case,
the averaging value is calculated with the middle position converted result counted twice (so a total of W + 1
converted results are averaged).
Table 1. Median Value Filter Size Selection
MEDIAN VALUE FILTER
M =
POSSIBLE AVERAGING WINDOW SIZE
W =
M1
0
M0
0
1
3
1, 4, 8, 16
1
0
1
1
0
7
1, 3
1
1
15
1, 3, 7
Table 2. Averaging Value Filter Size Selection
AVERAGING VALUE FILTER SIZE SELECTION
W =
W1
0
W0
0
M = 1 (Averaging Only)
M > 1
1
4
1
0
1
3
7
1
0
8
1
1
16
Reserved
17
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
NOTE: The default setting for MAVF is MVF (median value filter with averaging bypassed) for any invalid
configuration. For example, if (M1, M0, W1, W0) = (1,0,1,0), the MAVF performs as it was configured for
(1,0,0,0), median filter only with filter size = 7 and no averaging. The only exception is M > 1 and (W1, W0) =
(1,1). This setting is reserved and should not be used.
Table 3. Combined MAV Filter Setting
M
W
INTERPRETATION
Bypass both MAF and AVF
Bypass MVF only
N =
W
OUTPUT
= 1
= 1
> 1
= 1
> 1
= 1
The converted result
W
Average of W converted results
Median of M converted results
Bypass AVF only
M
Average of middle W of M converted results with the median
counted twice
> 1
> 1
M > W
M
The MAV filter is available for all analog inputs including the touch screen inputs, temperature measurements
TEMP1 and TEMP2, and the AUX measurement.
Averaging output
from window W
W
M = 1
N
N Acquired
Data
N measurements input
into temporary array
Sort by
descending order
Median value
from array M
N
M > 1 and W = 1
N
N
M
M
Averaging output
from window W
W
M > 1 and W > 1
Figure 26. MAV Filter Operation (patent pending)
Zone Detection
The Zone Detection unit is capable of screening all processed data from the MAVF and retaining only the data
of interest (data that fit the prerequisite). This unit can be programmed to send an alert if a predefined condition
set by two threshold value registers is met. Three different zones may be set:
1. Above the upper limit (X ≥ Threshold High)
2. Between the two thresholds (Threshold Low < X < Threshold High)
3. Below the lower limit (X ≤ Threshold Low)
The AUX and temperatures TEMP1 and TEMP2 have separate threshold value registers that can be enabled or
disabled. This function is not available to the touch screen inputs. Once the preset condition is met, the DAV
output to the PINTDAV pin is pulled low and the corresponding DAV bit is set.
18
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
DIGITAL INTERFACE
The TSC2005 communicates through a standard SPI bus. The SPI allows full-duplex, synchronous, serial
communication between a host processor (the master) and peripheral devices (slaves). The SPI master
generates the synchronizing clock and initiates transmissions. The SPI slave devices depend on a master to
start and synchronize transmissions.
A transmission begins when initiated by a master SPI. The byte from the master SPI begins shifting in on the
slave SDI (MOSI—master out, slave in) pin under the control of the master serial clock. As the byte shifts in on
the SDI (MOSI) pin, a byte shifts out on the SDO (MISO—master in, slave out) pin to the master shift register.
The idle state of the TSC2005 serial clock is logic low, which corresponds to a clock polarity setting of 0 (typical
microprocessor SPI control bit CPOL = 0). The TSC2005 interface is designed so that with a clock phase bit
setting of 0 (typical microprocessor SPI control bit CPHA = 0), the master begins driving its MOSI pin and the
slave begins driving its MISO pin half an SCLK before the first serial clock edge. The CS (SS, slave select) pin
can remain low between transmissions.
Table 4. Standard SPI Signal Names vs Common Serial Interface Signal Names
SPI SIGNAL NAMES
SS (Slave Select)
COMMON SERIAL INTERFACE NAMES
CS (Chip Select)
MISO (Master In Slave Out)
MOSI (Master Out Slave In)
SDO (Serial Data Out)
SDI (Serial Data In)
CONTROL BYTE
Table 5. Control Byte Format:
Start a Conversion and Mode Setting
MSB
D7
LSB
D0
D6
D5
D4
D3
D2
D1
1
C3
C2
C1
C0
RM
SWRST
STS
R/W
(Control Byte 1)
0
Reserved
(Write '0')
A3
A2
A1
A0
PND0
(Control Byte 0)
Table 6. Control Byte 1 Bit Register Description (D7 = 1)
BIT
D7
NAME
Control Byte ID
C3-C0
DESCRIPTION
1
D6-D3
Converter Function Select as detailed in Table 7
0: 10 Bit
D2
RM
1: 12 Bit
Software Reset
D1
D0
SWRST
STS
1: Reset all register values to default
Stop bit for all converter functions
Bit D7: Control Byte ID
1: Control Byte 1 (start conversion and channel select and conversion-related configuration).
0: Control Byte 0 (read/write data registers and non-conversion-related controls).
Bits D6-D3: C3-C0
Converter function select bits. These bits select the input to be converted, and the converter function to be
executed. Table 7 lists the possible converter functions.
19
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
Table 7. Converter Function Select
C3
C2
C1
C0
FUNCTION
Touch screen scan function: X, Y, Z1, and Z2 coordinates converted and the results returned
0
0
0
0
to X, Y, Z1, and Z2 data registers. Scan continues until either the pen is lifted or a stop bit is
sent.
Touch screen scan function: X and Y coordinates converted and the results returned to X and
Y data registers. Scan continues until either the pen is lifted or a stop bit is sent.
0
0
0
0
0
0
0
1
1
1
0
1
Touch screen scan function: X coordinate converted and the results returned to X data
register.
Touch screen scan function: Y coordinate converted and the results returned to Y data
register.
Touch screen scan function: Z1 and Z2 coordinates converted and the results returned to Z1
and Z2 data registers.
0
0
0
1
1
1
0
0
1
0
1
0
Auxiliary input converted and the results returned to the AUX data register.
A temperature measurement is made and the results returned to the Temperature
Measurement 1 data register.
A differential temperature measurement is made and the results returned to the Temperature
Measurement 2 data register.
0
1
1
1
0
0
1
0
0
1
0
1
Auxiliary input is converted continuously and the results returned to the AUX data register.
Touch screen panel connection to X-axis drivers is tested. The test result is output to
PINTDAV and shown in STATUS register.
Touch screen panel connection to Y-axis drivers is tested. The test result is output to
PINTDAV and shown in STATUS register.
1
1
1
0
0
1
1
1
0
0
1
0
RESERVED (Note: any condition caused by this command can be cleared by setting the STS
bit to 1).
Touch screen panel short-circuit (between X and Y plates) is tested through Y-axis. The test
result is output to PINTDAV and shown in the STATUS register.
1
1
1
1
1
1
0
1
1
1
0
1
Turn on X+, X– drivers
Turn on Y+, Y– drivers
Turn on Y+, X– drivers
Touch Screen Scan Function for XYZ or XY
C3-C0 = 0000 or 0001: These scan functions can collaborate with the PSM bit that defines the control mode of
converter functions. If the PSM bit is set to '1', these scan function select commands are recommended to be
issued before a pen touch is detected in order to allow the TSC2005 to initiate and control the scan processes
immediately after the screen is touched. If these functions are not issued before a pen touch is detected, the
TSC2005 will wait for the host to write these functions before starting a scan process. If PSM stays as '1' after a
TSC-initiated scan function is complete, the host is not required to write these function select bits again for each
of the following pen touches after the detected touch. In the host-controlled converter function mode (PSM = 0),
the host must send these functions select bits repeatedly for each scan function after a detected pen touch.
Touch Screen Sensor Connection Tests for X-Axis and Y-Axis
Range of resistances of different touch screen panels can be selected by setting the TBM bits in CFR1; see
Table 20. Once the resistance of the sensor panel is selected, two continuity tests are run separately for the
X-axis and Y-axis. The unit under test must pass both connection tests to ensure that a proper connection is
secured.
C3-C0 = 1001: PINTDAV = 0 during this connection test. A '1' shown at end of the test indicates the X-axis
drivers are well-connected to the sensor; otherwise, X-axis drivers are poorly connected. If drivers fail to
connect, then PINTDAV stays low until a stop bit (STS set to '1') is issued.
C3-C0 = 1010: PINTDAV = 0 during this connection test. A '1' shown at end of the test indicates the Y-axis
drivers are well-connected to the sensor; otherwise, Y-axis drivers are poorly connected. If the drivers are fail to
connect, then PINTDAV stays low until a stop bit (STS set to '1') is issued.
20
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
Touch Sensor Short-Circuit Test
If the TBM bits of CFR1 detailed in Table 20 are all set to '1', a short-circuit in the touch sensor can be detected.
C3-C0 = 1011: Reserved.
C3-C0 = 1100: PINTDAV = 0 during this short-circuit test. A '1' shown at end of the test indicates there is no
short-circuit detected (through Y-axis) between the flex and stable layers. If there is a short-circuit detected,
PINTDAV stays low until a stop bit (STS set to '1') is issued.
RM—Resolution select. If RM = 1, the conversion result resolution is 12-bit; otherwise, the resolution is 10-bit.
This bit is the same RM bit shown in CFR0.
SWRST—Software reset input. All register values are set to default value if a '1' is written to this bit. This bit
must be set to '0' in Control Byte 1 in order to cancel the software reset and resume normal operation.
STS—Stop bit for all converter functions. When writing a '1' to this register, this bit abortss the converter function
currently running in the TSC2005. A '0' must be written to this register in order to end the stop bit. This bit can
only stop converter functions; it does not reset any data, status, or configuration registers. This bit is the same
STS bit shown in CFR0, but can only be read through the CFR0 register with different interpretations.
Table 8. STS Bit Operation
OPERATION
Write
VALUE
DESCRIPTION
0
1
Normal operation
Write
Stop converter functions and power down
Table 9. Control Byte 0 Bit Register Description (D7 = 0)
BIT
NAME
DESCRIPTION
1: Control Byte 1—start conversion, channel select, and converison-related configuration
0: Control Byte 0—read/write data registers and non-conversion-related controls
Register Address Bits as detailed in Table 10
D7
Control Byte ID
D6-D3
D2
A3-A0
RESERVED
A '0' must be set in this bit for normal operation
Power Not Down Control
1: A/D converter biasing circuitry is always on between conversions, but is shut down after the converter
function stops
D1
D0
PND0
R/W
0: A/D converter biasing circuitry is shut down either between conversions or after the converter function
stops
TSC Internal Register Data Flow Control
1: Read from TSC internal registers
0: Write to TSC internal registers
21
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
Table 10. Internal Register Map
REGISTER ADDRESS
A3
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
A2
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
A1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
A0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
REGISTER CONTENT
READ/WRITE
X measurement result
Y measurement result
Z1 measurement result
Z2 measurement result
AUX measurement result
Temp1 measurement result
Temp2 measurement result
Status
R
R
R
R
R
R
R
R
AUX high threshold
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R
AUX low threshold
Temp high threshold (apply to both TEMP1 and TEMP2)
Temp low threshold (apply to both TEMP1 and TEMP2)
CFR0
CFR1
CFR2
Converter function select status
R/W—Register read and write control. A '1' indicates the contents of the internal register addressed by A3-A0
are sent to SDO at the next SPI interface clock cycle. A '0' indicates the data following Control Byte 0 on SDI are
written into registers addressed by A3-A0.
START A CONVERTER FUNCTION (CONTROL BYTE 1)
Control Byte 1 must begin with D7 = 1, as shown in Figure 27. Control Byte 1 starts the converter function that is
chosen by C3-C0, as shown in Table 7. After sending Control Byte 1, the master does not need to hold CS low,
and can release CS for operating other slave devices that share the same SCLK. After the converter function
completes or stops, the preprocessed data or data set are stored in data registers and can be read by sending
Control Byte 0 with Read Bit and a proper address in A3-A0. For the detailed operating procedures, see the
Operation section.
Control Byte 1 Write
CS
(SS)
1
2
3
4
5
6
7
8
SCLK
D7
D5
D4
D3
D2
D1
D0
D6
SDI
1
(MOSI)
MSB
LSB
Figure 27. Interface Timing — Control Byte 1
22
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
REGISTER ACCESS (Control Byte 0 with R/W Bit)
Control byte 0, beginning with D7 = 0, is used to access the internal registers. This control byte uses the last bit,
D0, to control the flow of data. If D0 is '1', then the content of the register pointed by the address bits (A3-A0) is
output to SDO (MISO) in the next cycle. Otherwise, the data coming from SDI (MOSI) is written to the register
properly pointed to by the address bits in the control byte (if the write mode is available for the pointed register).
After Control Byte 0 with Read/Write Bit followed by a 16-bit word on SDO/SDI completes, the master can hold
CS low to send another Control Byte 0 with Read/Write Bit followed by a 16-bit word on SDO/SDI as many times
as the master manages to operate.
Read Register Via Control Byte 0
CS
(SS)
1
2
3
4
5
6
7
8
1
2
3
7
8
11
15
16
SCLK
D7
D6
A3
D5
A2
D4
A1
D3
A0
D2
D1
D0
SDI
0
1
0
(MOSI)
MSB
LSB
D15 D14 D13 D9
D8
D5
D4
D1
D0
SDO
Hi-Z
Hi-Z
(MISO)
MSB
LSB
Figure 28. Interface Timing — Sending Control Byte 0 with Read Bit
Write to Register Via Control Byte 0
CS
(SS)
1
2
3
4
5
6
7
8
1
2
3
7
8
11
12
15
16
SCLK
D15 D14 D13 D9
D8
D5
D4
D1
D0
D7
D6
A3
D5
A2
D4
A1
D3
A0
D2
D1
D0
SDI
0
0
(MOSI)
MSB
LSB
MSB
LSB
SDO
Hi-Z
(MISO)
Figure 29. Interface Timing — Sending Control Byte 0 with Write Bit
23
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
COMMUNICATION PROTOCOL
The TSC2005 is controlled entirely by registers. Reading and writing to these registers are accomplished by the
use of Control Byte 0, which includes a 4-bit address plus one read/write TSC register control bit. The data
registers defined in Table 10 are all 16-bit, right-adjusted. NOTE: Except for some configuration registers and
the Status register that are full 16-bit registers, the rest of the value registers are 12-bit (or 10-bit) data preceded
by four (or six) zeros.
Configuration Register 0
Table 11. Configuration Register 0 (Reset Value = 4000h for Read; 0000h for Write)
MSB
D15
LSB
D0
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
PSM
STS
RM
CL1
CL0
PV2
PV1
PV0
PR2
PR1
PR0
SN2
SN1
SN0
DTW
LSM
PSM—Pen status/control mode. Reading this bit allows the host to determine if the screen is touched. Writing to
this bit selects the mode used to control the flow of converter functions that are either initiated and/or controlled
by host or under control of the TSC2005 responding to a pen touch. When reading, the PSM bit indicates if the
pen is down or not. When writing to this register, this bit determines if the TSC2005 controls the converter
functions, or if the converter functions are host-controlled. The default state is the host-controlled converter
function mode (0). The other state (1) is the TSC-initiated scan function mode that must only collaborate with
C3-C0 = 0000 or 0001 in order to allow the TSC2005 to initiate and control the scan function for XYZ or XY
when a pen touch is detected.
Table 12. PSM Bit Operation
OPERATION
Read
VALUE
DESCRIPTION
0
1
0
1
No screen touch detected
Read
Screen touch detected
Write
Converter functions initiated and/or controlled by host
Converter functions initiated and controlled by the TSC2005
Write
STS—A/D converter status. When reading, this bit indicates if the converter is busy or not busy. Continuous
scans or conversions can be stopped by writing a '1' to this bit, immediately aborting the running converter
function (even if the pen is still down) and causing the A/D converter to power down. The default state for write
is 0 (normal operation), and the default state for read is 1 (converter is not busy). NOTE: The same bit can be
written through Control Byte 1.
Table 13. STS Bit Operation
OPERATION
Read
VALUE
DESCRIPTION
0
1
0
1
Converter is busy
Read
Converter is not busy
Normal operation
Write
Write
Stop converter function and power down
RM—Resolution control. The A/D converter resolution is specified with this bit. See Table 14 for a description of
these bits. This bit is the same whether reading or writing, and defaults to 0. Note that the same bit can be
written through Control Byte 1.
Table 14. A/D Converter Resolution Control
RM
0
FUNCTION
10-bit resolution. Power-up and reset default.
12-bit resolution
1
24
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
CL1, CL0—Conversion clock control. These two bits specify the clock rate that the A/D converter uses to
perform conversion, as shown in Table 15. These bits are the same whether reading or writing.
Table 15. A/D Converter Conversion Clock Control
CL1
0
CL0
0
FUNCTION
fADC = fOSC/1. This is referred to as the 4MHz A/D converter clock rate, 10-bit resolution only.
fADC = fOSC/2. This is referred to as the 2MHz A/D converter clock rate.
fADC = fOSC/4. This is referred to as the 1MHz A/D converter clock rate.
Reserved
0
1
1
0
1
1
PV2-PV0—Panel voltage stabilization time control. These bits specify a delay time from the moment the touch
screen drivers are enabled to the time the voltage is sampled and a conversion is started. These bits allow the
user to adjust the appropriate settling time for the touch panel and external capacitances. See Table 16 for
settings of these bits. The default state is 000, indicating a 0µs stabilization time. These bits are the same
whether reading or writing.
Table 16. Panel Voltage Stabilization Time Control
PV2
0
PV1
0
PV0
0
STABILIZATION TIME (tPVS)
0µs
100µs
500µs
1ms
0
0
1
0
1
0
0
1
1
1
0
0
5ms
1
0
1
10ms
50ms
100ms
1
1
0
1
1
1
PR2-PR0—Precharge time selection. These bits set the amount of time allowed for precharging any pin
capacitance on the touch screen prior to sensing if a pen touch is happening.
Table 17. Precharge Time Selection
PR2
0
PR1
0
PR0
0
PRECHARGE TIME(tPRE)
20µs
84µs
0
0
1
0
1
0
276µs
0
1
1
340µs
1
0
0
1.044ms
1.108ms
1.300ms
1.364ms
1
0
1
1
1
0
1
1
1
SNS2-SNS0—Sense time selection. These bits set the amount of time the TSC2005 waits to sense whether the
screen is touched after converting a coordinate.
25
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
Table 18. Sense Time Selection
SNS2
SNS1
SNS0
SENSE TIME (tSNS)
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
32µs
96µs
544µs
608µs
2.080ms
2.144ms
2.592ms
2.656ms
DTW—Detection of pen touch in wait (patent pending). Writing a '1' to this bit enables the pen touch detection in
background while waiting for the host to issue the converter function in host-initiated/controlled modes. This
detection in background allows the TSC2005 to pull high at PINTDAV to indicate no pen touch detected while
waiting for the host to issue the converter function. If the host polls a high state at PINTDAV before the convert
function is sent, the host can abort the issuance of the convert function and stay in the polling PINTDAV mode
until the next pen touch is detected.
LSM—Longer sampling mode. When this bit is set to '1', the extra 500ns of sampling time is added to the
normal sampling cycles of each conversion. This additional time is represented as approximatly two A/D
converter clock cycles set by CL1-CL0.
Configuration Register 1
Configuration register 1 (CFR1) defines the connection test-bit modes configuration and the batch delay
selection.
Table 19. Configuration Register 1 (Reset Value = 0000h)
MSB
D15
LSB
D0
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
Resrvd Resrvd Resrvd Resrvd TBM3 TBM2 TBM1 TBM0
Resrvd
Resrvd
Resrvd
Resrvd
Resrvd
BTD2
BTD1
BTD0
TBM3-TBM0—Connection test-bit modes (patent pending). These bits specify the mode of test bits used for the
predefined range of the combined X-axis and Y-axis touch screen panel resistance (RTS).
Table 20. Touch Screen Resistance Range and Test-Bit Modes
TEST-BIT MODES
RTS
TBM3
TBM2
TBM1
TBM0
(kΩ)
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0.17
0.17 < RTS ≤ 0.52
0.52 < RTS ≤ 0.86
0.86 < RTS ≤ 1.6
1.6 < RTS ≤ 2.2
2.2 < RTS ≤ 3.6
3.6 < RTS ≤ 5.0
5.0 < RTS ≤ 7.8
7.8 < RTS ≤ 10.5
10.5 < RTS ≤ 16.0
16.0 < RTS ≤ 21.6
21.6 < RTS ≤ 32.6
Reserved
Reserved
Reserved
Only for short-circuit panel test
26
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
BTD2-BTD0—Batch Time Delay mode. These are the selection bits that specify the delay before a
sample/conversion scan cycle is triggered. When it is set, Batch Time Delay mode uses a set of timers to
automatically trigger a sequence of sample-and-conversion events. The mode works for both TSC-initiated
scans (XYZ or XY) and host-initiated scans (XYZ or XY).
A TSC-initiated scan (XYZ or XY) can be configured by setting the PSM bit in CFR0 to '1' and C[3:0] in Control
Byte 1 to '0000' or '0001'. In the case of a TSC-initiated scan (XYZ or XY), the sequence begins with the TSC
responding to a pen touch. After the first processed sample set completes during the batch delay, the scan
enters a wait mode until the end of the batch delay is reached. If a pen touch is still detected at that moment, the
scan continues to process the next sample set, and the batch delay is resumed. The throughput of the
processed sample sets (shown in Table 21 as sample sets per second, or SSPS) is regulated by the selected
batch delay during the time of the detected pen touch. A TSC-initiated scan (XYZ or XY) can be configured by
setting the PSM bit in CFR0 to '1' and C[3:0] in Control Byte 1 to '0000' or '0001'. Note that the throughput of the
processed sample set also depends on the settings of stabilization, precharge, and sense times, and the total
number of samples to be processed per coordinates. If the accrual time of these factors exceeds the batch delay
time, the accrual time dominates. Batch delay time starts when the pen touch initiates the scan function that
converts coordinates.
A host-initiated scan (XYZ or XY) can be configured by setting the PSM bit in CFR0 to '0' and C[3:0] in Control
Byte 1 to '0000' or '0001'. For the host-initiated scan (XYZ or XY), the host must set TSC internal register C[3:0]
in Control Byte 1 to '0000' or '0001' initially after a pen touch is detected; see Conversion Controlled by
TSC2005 Initiated by Host (TSMode 2), in the Theory of Operation section. After the scan (XYZ or XY) is
engaged, the throughput of the processed sample sets is regulated by the selected batch delay timer, as long as
the initial detected touch is not interrupted.
Table 21. Touch Screen Throughput and Batch Selection Bits
BATCH DELAY SELECTION
THROUGHPUT FOR TSC-INITIATED
OR HOST-INITIATED SCAN, XYZ OR XY
(SSPS)
DELAY TIME
(ms)
BTD2
BTD1
BTD0
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
Normal operation throughput depends on settings.
1000
500
250
100
50
2
4
10
20
40
100
25
10
For example, if stabilization time, precharge time, and sense time are selected as 100µs, 84µs, and 96µs,
respectively, and the batch delay time is 2ms, then the scan function enters wait mode after the first processed
sample set until the 2ms of batch delay time is reached. When the scan function starts to process the second
sample set (if the screen is still touched), the batch delay restarts at 2ms (in this example). This procedure
remains regulated by 2ms until the pen touch is not detected or the scan function is stopped by a stop bit or any
reset form.
27
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
Configuration Register 2
Configuration register 2 (CFR2) defines the preprocessor configuration.
Table 22. Configuration Register 2 (Reset Value = 0000h)
MSB
D15
LSB
D0
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
MAVE
X
MAVE MAVE
MAVE
AUX
MAVE
TEMP
PINTS1 PINTS0
M1
M0
W1
W0
TZ1
TZ0
AZ1
AZ0
Resrvd
Y
Z
PINTS1 (default 0)—This bit controls the output format of the PINTDAV pin. When this bit is set to '0', the output
format is shown as the AND-form of internal signals of PENIRQ and DAV). When this bit is set to '1', PINTDAV
outputs PENIRQ only.
PINTS0 (default 0)—This bit selects what is output on the PINTDAV pin. If this bit set to '0', the output format of
PINTDAV depends on the selection made on the PINTS1 bit. If this bit set to '1', the internal signal of DAV is
output on PINTDAV.
Table 23. PINTSx Selection
PINTS1
PINTS0
PINTDAV PIN OUTPUT =
0
0
1
1
0
1
0
1
An AND combination of PENIRQ (active low) and DAV (active high).
Data available, DAV (active low).
An interrupt, PENIRQ (active low) generated by pen-touch.
Data available, DAV (active low).
M1, M0, W1, W0 (default 0000)—Preprocessing MAV filter control. Note that when the MAV filter is processing
data, the STS bit and the corresponding DAV bits in the status register will indicate that the converter is busy
until all conversions necessary for the preprocessing are complete. The default state for these bits is 0000,
which bypasses the preprocessor. These bits are the same whether reading or writing.
TZ1 and TZ0, or AZ1 and AZ0 (default 00)—Zone detection bit definition (for TEMP or AUX measurements).
TZ1 and TZ0 are for the TEMP measurement. AZ1 and AZ0 are for the AUX measurement. The action taken in
zone detection is to store the processed data in the corresponding data registers and to update the
corresponding DAV bits in status register. If the processed data do not meet the selected criteria, these data are
ignored and the corresponding DAV bits are not updated. When zone detection is disabled, the processed data
are simply stored in the corresponding data registers and the corresponding DAV bits are updated without any
comparison of criteria. Note that the converted samples are always processed according to the setting of the
MAVE bits for AUX/TEMP before zone detection takes effect. See Table 30 for thresholds.
Table 24. Zone Detection Bit Definition
TZ1/AZ1
TZ0/AZ0
FUNCTION
0
0
1
1
0
1
0
1
Zone detection is disabled.
When the processed data is below low threshold
When the processed data is between low and high thresholds
When the processed data is above high threshold
MAVE (default is 00000)—MAV filter function enable bit. When the corresponding bit is set to 1, the MAV filter
setup is applied to the corresponding measurement.
28
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
Converter Function Select Register
The Converter Function Select (CFN) register reflects the converter function select status.
Table 25. Converter Function Select Status Register (Reset Value = 0000h)
MSB
D15
LSB
D0
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
CFN15 CFN14 CFN13 CFN12 CFN11 CFN10 CFN9
CFN8
CFN7
CFN6
CFN5
CFN4
CFN3
CFN2
CFN1
CFN0
CFN15-CFN0—Converter function select status. These bits represent the current running converter function that
is set in bits C3-C0 of Control Byte 1. When the CFNx bit shows '1', where x is the decimal value of converter
function select bits C3-C0, it indicates that the converter function that is set in bits C3-C0 is running. For
example, when CFN2 shows '1', it indicates that the converter function set in bits C3-C0 ('0010') is running.
These bits are reset to 0000h whenever the converter function is complete, stopped by STS bit, or reset by the
hardware reset from the RESET pin or the software reset from SWRST bit in Control Byte 1. However, if the
TSC-initiated scan function mode is issued by setting the PSM bit in the CFR0 register to '1', these bits will not
be reset when the converter function is complete because there is no detection of pen touch. This allows the
TSC2005 to initiate the scan process immediately when the next pen touch is detected.
Table 26. STATUS Register (Reset Value = 0004h)
MSB
D15
LSB
D0
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
DAV
Due
X
DAV
Due
Y
DAV
Due
Z1
DAV
Due
Z2
DAV
Due
AUX
DAV
Due
TEMP1 TEMP2
DAV
Due
RESRVD RESET
(read '0') Flag
X
CON
Y
CON
RESRVD
(read '0')
Y
SHR
PDST
ID1
ID0
DAV Bits—Data available bits. These seven bits mirror the operation of the internal signals of DAV. When any
processed data are stored in data registers, the corresponding DAV bit is set to '1'. It stays at '1' until the
register(s) updated to the processed data have been read out by the host.
Table 27. DAV Function
DAV
DESCRIPTION
0
1
No new processed data are available.
Processed data are available. This will stay at 1 until the host has read out all updated registers.
RESET Flag—See Table 28 for the interpretation of the RESET flag bits.
Table 28. RESET Flag Bits
RESET Flag
DESCRIPTION
0
1
Device was reset since last status poll (hardware or software reset).
Device has not been reset since last status poll.
X CON—This bit is '1' if the X axis of the touch screen panel is properly connected to the X drivers. This bit is
the connection test result.
Y CON—This bit is '1' if the Y axis of the touch screen panel is properly connected to the Y drivers. This bit is
the connection test result.
Y SHR—This bit is '1' if there is no short-circuit tested at the Y axis of the touch screen panel. This bit is the
short-circuit test result.
PDST—Power down status. This bit reflects the setting of the PND0 bit in Control Byte 0. When this bit shows
'0', it indicates ADC bias circuitry is still powered on after each conversion and before the next sampling;
otherwise, it indicates ADC bias circuitry is powered down after each conversion and before the next sampling.
However, it is powered down between conversion sets. Because this status bit is synchronized with the internal
clock, it does not reflect the setting of the PND0 bit until a pen touch is detected or a converter function is
running.
ID[1:0] Device ID bits: These bits represent the version ID of TSC2005. This version defaults to '00'.
29
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
DATA REGISTERS
The data registers of the TSC2005 hold data results from conversions. All of these registers default to 0000h
upon reset.
X, Y, Z1, Z2, AUX, TEMP1 and TEMP2 REGISTERS
The results of all A/D conversions are placed in the appropriate data registers, as described in Table 10. The
data format of the result word (R) of these registers is right-justified, as shown in Table 29:
Table 29. Internal Register Format
MSB
D15
LSB
D0
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
0
0
0
0
R11
R10
R9
R8
R7
R6
R5
R4
R3
R2
R1
R0
Register Map
The TSC2005 has several 16-bit registers that allow control of the device, as well as providing a location to store
results from the TSC2005 until read out by the host microprocessor. Table 30 shows the memory map.
Table 30. Register Content and Reset Values(1)
RESET
A3-A0
(HEX)
REGISTER
NAME
VALUE
(HEX)
D15
0
D14
0
D13
0
D12
0
D11
R11
R11
R11
R11
R11
R11
R11
D10
R10
R10
R10
R10
R10
R10
R10
D9
R9
R9
R9
R9
R9
R9
R9
D8
R8
R8
R8
R8
R8
R8
R8
D7
R7
R7
R7
R7
R7
R7
R7
D6
R6
R6
R6
R6
R6
R6
R6
D5
R5
R5
R5
R5
R5
R5
R5
D4
R4
R4
R4
R4
R4
R4
R4
D3
R3
R3
R3
R3
R3
R3
R3
D2
R2
R2
R2
R2
R2
R2
R2
D1
R1
R1
R1
R1
R1
R1
R1
D0
R0
R0
R0
R0
R0
R0
R0
0
1
2
3
4
5
6
X
Y
0000
0000
0000
0000
0000
0000
0000
0
0
0
0
Z1
0
0
0
0
Z2
0
0
0
0
AUX
Temp1
Temp2
0
0
0
0
0
0
0
0
0
0
0
0
Rsvd
7
Status
S15
S14
S13
S12
S11
S10
S9
0
S7
S6
S5
S3
S2
S1
S0
0004
(2)
8
9
AUX High
AUX Low
Temp High
Temp Low
CFR0
0
0
0
0
0
0
0
0
R11
R11
R11
R11
R11
R11
R11
R10
R10
R10
R10
R10
R10
R10
R9
R9
R9
R9
R9
R9
R9
R8
R8
R8
R8
R8
R8
R8
R7
R7
R7
R7
R7
0
R6
R6
R6
R6
R6
0
R5
R5
R5
R5
R5
0
R4
R4
R4
R4
R4
0
R3
R3
R3
R3
R3
0
R2
R2
R2
R2
R2
R2
R2
R1
R1
R1
R1
R1
R1
R1
R0
R0
R0
R0
R0
R0
R0
0FFF
0000
0FFF
0000
4000
0000
0000
A
B
C
D
E
0
0
0
0
0
0
0
0
R15
0
R14
0
R13
0
R12
0
CFR1
CFR2
R15
R14
R13
R12
R7
R6
0
R4
R3
Converter
Function
Rsvd
F
R15
R14
R13
R12
R10
R9
R8
R7
R6
R5
R4
R3
R2
R1
R0
0000
(2)
Select Status
(1) For all combination bits, the pattern marked as reserved must not be used. The default pattern is read back after reset.
(2) This bit is reserved.
30
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
REGISTER RESET
There are three way to reset the TSC2005. First, at power-on, a power good signal will generate a prolonged
reset pulse internally to all registers.
Second, an external pin, RESET, is available to perform a system reset or allow other peripherals (such as a
display) to reset the device if the pulse meets the timing requirement (at least 10µs wide). Any RESET pulse
less than 5µs will be rejected. To accommodate the timing drift between devices because of process variation, a
RESET pulse width between 5µs to 10µs falls into the gray area that will not be recognized and the result is
undetermined; this situation should be avoided. Refer to Figure 30 for details. A good reset pulse must be low
for at least 10µs. There is an internal spike filter to reject spikes up to 20ns wide.
tR
tR
tWL(RESET) < 5ms
tWL(RESET) ³ 10ms
RESET
State
Normal Operation
Resetting
Initial Condition
Figure 30. External Reset Timing
Finally, a software reset can be activated by writing a '1' to CB1.1 (bit 1 of control byte 1). It should be noted this
reset is not self-cleared, so the user must write a '0' to remove the software reset.
A reset clears all registers and loads default values. A power-on reset and external (hardware) reset take
precedence over a software reset. If a software reset not cleared by the user, it will be cleared by either a
power-on reset or an external (hardware) reset.
31
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
THEORY OF OPERATION
TOUCH SCREEN MEASUREMENTS
As noted previously in the discussion of the A/D converter, several operating modes can be used that allow
great flexibility for the host processor. This section examines these different modes.
Conversion Controlled by TSC2005 Initiated by TSC2005 (TSMode 1)
In TSMode 1, before a pen touch can be detected, the TSC2005 must be programmed with PSM = 1 and one of
two scan modes:
1. X-Y-Z Scan (converter function select bits C[3:0] = Control Byte 1 D[6:3] = 0000); or
2. X-Y Scan (converter function select bits C[3:0] = Control Byte 1 D[6:3] = 0001).
See Table 7 for more information on the converter function select bits.
When the touch panel is touched, which causes the internal pen-touch signal to activate, the PINTDAV output is
lowered if it is programmed as PENIRQ. The TSC2005 then executes the preprogrammed scan function without
a host intervention.
At the same time, the TSC2005 starts up its internal clock. It then turns on the Y-drivers, and after a
programmed panel voltage stabilization time, powers up the A/D converter and converts the Y coordinate. If
preprocessing is selected, several conversions may take place. When data preprocessing is complete, the Y
coordinate result is stored in a temporary register.
If the screen is still touched at this time, the X-drivers are enabled, and the process repeats, but measuring the
X coordinate instead, and storing the result in a temporary register.
If only X and Y coordinates are to be measured, then the conversion process is complete. A set of X and Y
coordinates are stored in the X and Y registers. Figure 31 shows a flowchart for this process. The time it takes
to go through this process depends upon the selected resolution, internal conversion clock rate, panel voltage
stabilization time, precharge and sense times, and whether preprocessing is selected. The time needed to get a
complete X and Y coordinate (sample set) reading can be calculated by:
f
LPPRO
fOSC
OHDLY1
fOSC
OH1
fOSC
1
fOSC
OSC )OHCONV
fADC
@
)
)2 @ ǒ
Ǔ)2 @ N @ ǒB)2 @
(
)
Ǔ ǒ Ǔ ǒ Ǔ
ǒ
Ǔ
tCOORDINATE
+
tPVS)tPRE)tSNS
)
(5)
Where:
tCOORDINATE = time to complete X/Y coordinate reading.
tPVS = panel voltage stabilization time, as given in Table 16.
tPRE = precharge time, as given in Table 17.
tSNS = sense time, as given in Table 18.
N = number of measurements for MAV filter input, as given in Table 3 as N.
(For no MAV: M1-0[1:0] = '00', W1-0[1:0] = '00', N = 1.)
B = number of bits of resolution.
fOSC = TSC onboard OSC clock frequency. See Electrical Characteristics for supply frequency (SNSVDD).
fADC = A/D converter clock frequency, as given in Table 15.
OH1 = overhead time #1 = 2.5 internal clock cycles.
OHDLY1 = total overhead time for tPVS, tPRE, and tSNS = 10 internal clock cycles.
OHCONV = total overhead time for A/D conversion = 3 internal clock cycles.
LPPRO = pre-processor preocessing time as given in Table 31.
32
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
THEORY OF OPERATION (continued)
Table 31. Preprocessing Delay
LPPRO
=
M =
1
W =
FOR B = 12 BIT
FOR B = 10 BIT
1, 4, 8, 16
2
2
3, 7
7
1
3
1
3
7
28
31
31
34
38
24
27
29
32
36
15
15
15
Programmed for
Self-Control
(PSM = 1)
X-Y Scan Mode
(Control Byte1
D[6:3] = 0001)
Reading Reading
X-Data Y-Data
Register Register
CS Deactivated
tCOORDINATE
Sample, Conversion, and
Preprocessing for
Y Coordinate
Sample, Conversion, and
Preprocessing for
X Coordinate
Sample, Conversion, and
Preprocessing for
Y Coordinate
Detecting
Touch
Detecting
Touch
Detecting
Touch
Detecting Touch
PINTDAV Programmed:
Touch is Detected
Touch is Detected
As PENIRQ,
CFR2, D[15:14] = 10
As DAV,
CFR2, D[15:14] = 11 or 01
Touch is Detected
As PENIRQ and DAV,
CFR2, D[15:14] = 00
Figure 31. Example of X and Y Coordinate Touch Screen Scan using TSMode 1
33
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
If the pressure of the touch is also to be measured, the process continues in the same way, but measuring the
Z1 and Z2 values instead, and storing the results in temporary registers. Once the complete sample set of data
(X, Y, Z1, and Z2) are available, they are loaded in the X, Y, Z1, and Z2 registers. This process is illustrated in
Figure 32. As before, this process time depends upon the settings previously described. The time for a complete
X, Y, Z1, and Z2 coordinate reading is given by:
f
LPPRO
fOSC
OHDLY1
fOSC
OH2
fOSC
1
fOSC
OSC )OHCONV
@
)
)3 @ ǒ
Ǔ)4 @ N @ ǒB)2 @
(
)
Ǔ ǒ Ǔ ǒ Ǔ
ǒ
Ǔ
tCOORDINATE
+
tPVS)tPRE)tSNS
)
fADC
(6)
Where:
OH2 = overhead time #2 = 3.5 internal clock cycles.
Programmed for
Self-Control
(PSM = 1)
Reading Reading Reading Reading
Z1-Data Z2-Data
Register Register Register Register
CS Deactivated
X-Data
Y-Data
X-Y-Z1-Z2 Scan Mode
(Control Byte1
D[6:3] = 0000)
tCOORDINATE
Sample, Conversion,
and Preprocessing for
Z1 Coordinate and Z2 Coordinate
Sample, Conversion,
and Preprocessing for
Y Coordinate
Sample, Conversion,
and Preprocessing for
X Coordinate
Sample, Conversion,
and Preprocessing for
Y Coordinate
Detecting
Touch
Detecting
Touch
Detecting
Touch
Detecting
Touch
Detecting
Touch
PINTDAV Programmed:
Touch is Detected
Touch is Detected
Touch is Detected
As PENIRQ,
CFR2, D[15:14] = 10
As DAV,
CFR2, D[15:14] = 11 or 01
Touch is Detected
As PENIRQ and DAV,
CFR2, D[15:14] = 00
Figure 32. Example of X, Y, and Z Coordinate Touch Screen Scan using TSMode 1
34
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
Conversion Controlled by TSC2005 Initiated by Host (TSMode 2)
In TSMode 2, the TSC2005 detects when the touch panel is touched and causes the internal Pen-Touch signal
to activate, which lowers the PINTDAV output if it is programmed as PENIRQ. The host recognizes the interrupt
request, and then writes to the A/D Converter Control register to select one of the two touch screen scan
functions:
1. X-Y-Z Scan (converter function select bits C[3:0] = Control Byte 1 D[6:3] = 0000); or
2. X-Y Scan (converter function select bits C[3:0] = Control Byte 1 D[6:3] = 0001).
See Table 7 for more information on the converter function select bits.
The conversion process then as shown in Figure 33; see previous sections for more details.
The main difference between this mode and the previous mode is that the host, not the TSC2005, decides when
the touch screen scan begins.
The time needed to convert both X and Y coordinates under host control (not including the time needed to send
the command over the SPI bus) is given by:
f
LPPRO
fOSC
OHDLY1
fOSC
OH1
fOSC
1
fOSC
OSC )OHCONV
fADC
@
)
)2 @ ǒ
Ǔ)2 @ N @ ǒB)2 @
(
)
Ǔ ǒ Ǔ ǒ Ǔ
ǒ
Ǔ
tCOORDINATE
+
tPVS)tPRE)tSNS
)
(7)
Programmed
for
Host-
Controlled
Mode
(PSM = 0)
CS
Deactivated
CS
Deactivated
CS
Deactivated
Programmed
Reading Reading
X-Data Y-Data
Register Register
for
X-Y
Scan Mode
tCOORDINATE
Waiting for Host to
Write Into
Control Byte 1 D[6:3]
Sample, Conversion,
and Preprocessing for
Y Coordinate
Sample, Conversion,
and Preprocessing for
Y Coordinate
Sample, Conversion,
and Preprocessing for
X Coordinate
Detecting
Touch
Detecting
Touch
Detecting
Touch
Detecting
Touch
PINTDAV Programmed:
Touch is Detected
As PENIRQ,
CFR2, D[15:14] = 10
Touch is Detected
As DAV,
CFR2, D[15:14] = 11 or 01
Touch is Still Here
As PENIRQ and DAV,
CFR2, D[15:14] = 00
Figure 33. Example of an X and Y Coordinate Touch Screen Scan using TSMode 2
35
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
Conversion Controlled by Host (TSMode 3)
In TSMode 3, the TSC2005 detects when the touch panel is touched and causes the internal Pen-Touch signal
to be active, which lowers the PINTDAV output if it is programmed as PENIRQ. The host recognizes the
interrupt request. Instead of starting a sequence in the TSC2005, which then reads each coordinate in turn, the
host must now control all aspects of the conversion. Generally, upon receiving the interrupt request, the host
turns on the X drivers. (NOTE: If drivers are not turned on, the device detects this condition and turns them on
before the scan starts. This situation is why the event of turn on drivers is shown as optional in Figure 34 and
Figure 35.) After waiting for the settling time, the host then addresses the TSC2005 again, this time requesting
an X coordinate conversion.
The process is then repeated for the Y and Z coordinates. The processes are outlined in Figure 34 and
Figure 35. Figure 34 shows two consecutive scans on X and Y. Figure 35 shows a single Z scan.
The time needed to convert any single coordinate X or Y under host control (not including the time needed to
send the command over the SPI bus) is given by:
f
LPPRO
fOSC
OHDLY2
fOSC
OH1
fOSC
1
fOSC
tCOORDINATE
+
OSC )OHCONV
fADC
ǒ
) tPRE)tSNS)
Ǔ)ǒN @ B)2 @
(
)
Ǔ@ ǒ Ǔ)ǒ Ǔ
(8)
Where:
OHDLY2 = total overhead time for tPRE and tSNS = 6 internal clock cycles.
Programmed for:
Programmed for:
Turn On
Programmed
for Host-
Controlled
Mode
(PSM = 0)
CS
Deactivated X+ and
Turn On
X
CS
Deactivated
CS
Deactivated
CS
Deactivated
Y
Scan
Reading
X-Data
Register
Reading
Y-Data
Register
Y+ and
Y-
Scan
Mode
X-
Mode
(1)
(1)
Drivers
Drivers
tCOORDINATE
tCOORDINATE
Sample, Conversion,
and Preprocessing
for X Coordinate
Sample, Conversion,
and Preprocessing
for Y Coordinate
Waiting for Host to
Write Into Control
Byte 1 D[6:3]
Detecting
Touch
Waiting for Host to Write Into
Control Byte 1 D[6:3]
Detecting Waiting for Host to Write Into
Detecting
Touch
Control Byte 1 D[6:3]
Touch
Touch is Detected
PINTDAV Programmed:
Touch is Detected
Touch is Detected
As PENIRQ,
CFR2, D[15:14] = 10
As DAV,
CFR2, D[15:14] = 11 or 01
As PENIRQ and DAV,
CFR2, D[15:14] = 00
NOTE: (1) Optional. If not turned on, it will be turned on by the Scan mode, once detected.
Figure 34. Example of X and Y Coordinate Touch Screen Scan using TSMode 3
36
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
The time needed to convert any Z1 and Z2 coordinate under host control (not including the time needed to send
the command over the SPI bus) is given by:
f
LPPRO
fOSC
OHDLY2
fOSC
OH2
fOSC
1
fOSC
tCOORDINATE
+
OSC )OHCONV
fADC
ǒ
) tPRE)tSNS)
Ǔ)ǒN @ B)2 @
(
)
Ǔ@ ǒ Ǔ)ǒ Ǔ
(9)
Programmed for:
Turn On
Programmed
for
Host-Controlled
Mode
(PSM = 0)
CS
Deactivated
CS
Deactivated
CS
Deactivated
Reading Reading
Z2-Data
Y+
and
Z
Z1-Data
Scan
Mode
Register Register
X-
Drivers(1)
tCOORDINATE
Sample, Conversion, Sample, Conversion,
Detecting
Touch
Detecting
Touch
Waiting for Host to Write
Into Control Byte 1 D[6:3]
Waiting for Host to Write
Into Control Byte 1 D[6:3]
and Preprocessing
for Z1 Coordinate
and Preprocessing
for Z2 Coordinate
PINTDAV Programmed:
Touch is Detected
Touch is Detected
As PENIRQ,
CFR2, D[15:14] = 10
As DAV,
CFR2, D[15:14] = 11 or 01
As PENIRQ and DAV,
CFR2D[15:14] = 00
NOTE: (1) Optional. If not turned on, it will be turned on by the Scan mode, once detected.
Figure 35. Example of Z1 and Z2 Coordinate Touch Screen Scan
(without Panel Stabilization Time) using TSMode 3
If the drivers are not turned on befire the touch screen mode is programmed, the panel stabilization time should
be included. In this case, the time needed to convert an single X or Y under host control (not including the time
needed to send the command over the SPI bus) is given by:
f
LPPRO
fOSC
OHDLY1
fOSC
OH2
fOSC
1
fOSC
tCOORDINATE
+
)
OSC )OHCONV
fADC
ǒ
) tPVS)tPRE)tSNS
Ǔ)ǒN @ B)2 @
(
)
Ǔ@ ǒ Ǔ)ǒ Ǔ
(10)
CS
Deactivated
CS
Deactivated
CS
Deactivated
Programmed
for
Z1-Z2
Programmed for
Host-Controlled
Mode
Reading Reading
Z2-Data
Z1-Data
Register Register
(PSM = 0)
Scan Mode
tCOORDINATE
Detecting
Touch
Detecting
Touch
Waiting for Host to Write Sample, Conversion, and
Into Control Byte 1 D[6:3] Preprocessing for Z1, Z2 Coordinates
Waiting for Host to Write
Into Control Byte 1 D[6:3]
PINTDAV Programmed:
Touch is Detected
As PENIRQ,
CFR2, D[15:14] = 10
As DAV,
CFR2, D[15:14] = 11 or 01
Touch is Still Here
As PENIRQ and DAV,
CFR2D[15:14] = 00
Figure 36. Example of a Z1 and Z2 Coordinate Touch Screen Scan
(with Panel Stabilization Time) using TSMode 3
37
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
The time needed to convert any single coordinate (either X or Y) under host control (not including the time
needed to send the command over the SPI bus) is given by:
f
LPPRO
fOSC
OHDLY1
fOSC
OH1
fOSC
1
fOSC
tCOORDINATE
+
)
OSC )OHCONV
fADC
ǒ
) tPVS)tPRE)tSNS
Ǔ)ǒN @ B)2 @
(
)
Ǔ@ ǒ Ǔ)ǒ Ǔ
(11)
CS
Deactivated
CS
Deactivated
CS
Deactivated
Programmed
Programmed for
Host-Controlled
Mode
Reading
X-Data
Register
for
X
(PSM = 0)
Scan Mode
tCOORDINATE
Detecting
Touch
Detecting
Touch
Waiting for Host to Write
Into Control Byte 1 D[6:3]
Sample, Conversion, and
Preprocessing for X Coordinate
Waiting for Host to Write
Into Control Byte 1 D[6:3]
PINTDAV Programmed:
Touch is Detected
As PENIRQ,
CFR2, D[15:14] = 10
As DAV,
CFR2, D[15:14] = 11 or 01
Touch is Still Here
As PENIRQ and DAV,
CFR2, D[15:14] = 00
Figure 37. Example of a Single X Coordinate Touch Screen Scan
(with Panel Stabilization Time) using TSMode 3
38
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
AUXILIARY AND TEMPERATURE MEASUREMENT
The TSC2005 can measure the voltage from the auxiliary input (AUX) and from the internal temperature sensor.
Applications for the AUX can include external temperature sensing, ambient light monitoring for controlling
backlighting, or sensing the current drawn from batteries. There are two converter functions that can be used for
the measurement of the AUX:
1. Non-continuous AUX measurement shown in Figure 38 (converter function select bits C[3:0] = Control
Byte 1 D[6:3] = 0101); or
2. Continuous AUX Measurement shown in Figure 39 (converter function select bits C[3:0] = Control Byte 1
D[6:3] = 1000).
See Table 7 for more information on the converter function select bits.
There are also two converter functions for the measurement of the internal temperature sensor:
1. TEMP1 measurement (converter function select bits C[3:0] = Control Byte 1 D[6:3] = 0110); or
2. TEMP2 measurement (converter function select bits C[3:0] = Control Byte 1 D[6:3] = 0111).
See Table 7 for more information on the converter function select bits.
For the detailed calculation of the internal temperature sensor, please see the SubSec1 9.3 section. These two
converter functions have the same timing as the non-continuous AUX measurement operation as shown in
Figure 38; therefore, Equation 12 can also be used for internal temperature sensor measurement. The time
needed to make a non-continuous auxiliary measurement or an internal temperature sensor measurement is
given by:
f
LPPRO
fOSC
OH3
fOSC
1
fOSC
OSC )OHCONV
fADC
)ǒN @ B)2 @
(
)
Ǔ@ ǒ Ǔ)ǒ Ǔ
tCOORDINATE
+
(12)
Where:
OH3 = overhead time #3 = 3.5 internal clock cycles.
CS
Deactivated
CS
Deactivated
CS
Deactivated
Reading
AUX-Data
Register
Programmed for
Non-Continuous
AUX Measurement
tCOORDINATE
No Touch
Detected
Sample, Conversion, and
Averaging for AUX Measurement
No Touch
Detected
Host Write to
Control Byte 1 D[6:3]
Waiting for Host to
Read AUX Data
As DAV
Figure 38. Non-Touch Screen, Non-Continuous AUX Measurement
The time needed to make continuous auxiliary measurement is given by:
f
LPPRO
fOSC
OH3
fOSC
1
fOSC
OSC )OHCONV
)ǒN @ B)2 @
(
)
Ǔ@ ǒ Ǔ)ǒ Ǔ
tCOORDINATE
+
fADC
(13)
CS
Deactivated
CS
Deactivated
CS
Deactivated
CS
Deactivated
Programmed for
Continuous
Reading
AUX-Data
Register
Reading
AUX-Data
Register
AUX Measurement
tCOORDINATE
tCOORDINATE
tCOORDINATE
Sample, Conversion,
and Averaging for
AUX Measurement
Sample, Conversion,
and Averaging for
AUX Measurement
Sample, Conversion,
and Averaging for
AUX Measurement
No Touch
Detected
Host to Write to
Control Byte 1 D[6:3]
As DAV
Figure 39. Non-Touch Screen, Continuous AUX Measurement
39
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
LAYOUT
The following layout suggestions should obtain optimum performance from the TSC2005. However, many
portable applications have conflicting requirements for power, cost, size, and weight. In general, most portable
devices have fairly clean power and grounds because most of the internal components are very low power. This
situation would mean less bypassing for the converter power and less concern regarding grounding. Still, each
situation is unique and the following suggestions should be reviewed carefully.
For optimum performance, care should be taken with the physical layout of the TSC2005 circuitry. The basic
SAR architecture is sensitive to glitches or sudden changes on the power supply, reference, ground
connections, and digital inputs that occur just prior to latching the output of the analog comparator. Therefore,
during any single conversion for an n-bit SAR converter, there are n windows in which large external transient
voltages can easily affect the conversion result. Such glitches might originate from switching power supplies,
nearby digital logic, and high power devices. The degree of error in the digital output depends on the reference
voltage, layout, and the exact timing of the external event. The error can change if the external event changes in
time with respect to the SCLK input.
With this in mind, power to the TSC2005 should be clean and well-bypassed. A 0.1µF ceramic bypass capacitor
should be added between (SNSVDD to AGND and SNSGND) or (I/OVDD to DGND). A 0.1µF decoupling
capacitor between VREF to AGND is also needed unless the SNSVDD is used as a reference input and is
connected to VREF. These capacitors need to be placed as close to the device as possible. A 1µF to 10µF
capacitor may also be needed if the impedance of the connection between SNSVDD and the power supply is
high. The I/OVDD needs to be shorted to the same supply plane as the SNSVDD. Short both SNSVDD and
I/OVDD to the analog VDD plane.
The TSC2005 architecture offers no inherent rejection of noise or voltage variation in regards to using an
external reference input, which is of particular concern when the reference input is tied to the power supply. Any
noise and ripple from the supply will appear directly in the digital results. While high-frequency noise can be
filtered out, voltage variation due to line frequency (50Hz or 60Hz) can be difficult to remove. Some package
options have pins labeled as VOID. Avoid any active trace going under those pins marked as VOID unless they
are shielded by a ground or power plane.
All GND (AGND, DGND, SUBGND and SNSGND) pins should be connected to a clean ground point. In many
cases, this point will be the analog ground. Avoid connections that are too near the grounding point of a
microcontroller or digital signal processor. If needed, run a ground trace directly from the converter to the
power-supply entry or battery connection point. The ideal layout includes an analog ground plane dedicated to
the converter and associated analog circuitry.
In the specific case of use with a resistive touch screen, care should be taken with the connection between the
converter and the touch screen. Since resistive touch screens have fairly low resistance, the interconnection
should be as short and robust as possible. Loose connections can be a source of error when the contact
resistance changes with flexing or vibrations.
As indicated previously, noise can be a major source of error in touch-screen applications (for example,
applications that require a back-lit LCD panel). This electromagnetic interfence (EMI) noise can be coupled
through the LCD panel to the touch screen and cause flickering of the converted ADC data. Several things can
be done to reduce this error, such as using a touch screen with a bottom-side metal layer connected to ground,
which will couple the majority of noise to ground. Additionally, filtering capacitors, from Y+, Y–, X+, and X– to
ground, can also help. Note, however, that the use of these capacitors increases screen settling time and
requires longer panel voltage stabilization times, and also increases precharge and sense times for the
PINTADV circuitry of the TSC2005. The resistor value varies depending on the touch screen sensor used. The
internal 51kΩ resistor (RIRQ) may be adequate for most of sensors.
40
Submit Documentation Feedback
TSC2005
www.ti.com
SBAS379A–DECEMBER 2006–REVISED MAY 2007
REVISION HISTORY
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Original (December 2006) to A Revision ............................................................................................... Page
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Changed air gap discharge from 18kV to 25kV.................................................................................................................... 1
Changed contact discharge from 15kV to 12kV ................................................................................................................... 1
Added row for IEC contact discharge to Absolute Maximum Ratings.................................................................................. 2
Added row for IEC air discharge to Absolute Maximum Ratings.......................................................................................... 2
Changed logic level for VIH and VIL from "≤ 1.6V" to "< 1.6V". ............................................................................................. 3
Changed logic level for VIH (1.6V ≤ I/OVDD ≤ 3.6V) from 2.0 to 0.7 × I/OVDD .................................................................. 3
Changed Timing Characteristics table.................................................................................................................................. 6
Changed Figure 5 conditions................................................................................................................................................ 7
Changed Figure 6 conditions................................................................................................................................................ 7
Changed value and units for k (Boltzmann's constant) ...................................................................................................... 13
Changed value and units for q (electron charge) ............................................................................................................... 13
Changed BTD2-BTD0 paragraph text; reworded for better readability .............................................................................. 27
Changed two rows in Table 23 from "A delayed data_ava" to "Data available"................................................................. 28
Changed CFN15-CFN0 paragraph text; reworded for better readability............................................................................ 29
Changed Figure 32 ............................................................................................................................................................ 34
Changed Figure 33 ............................................................................................................................................................ 35
Added plus sign after tSNS to Equation 10........................................................................................................................... 37
Changed Figure 38 ............................................................................................................................................................ 39
41
Submit Documentation Feedback
PACKAGE OPTION ADDENDUM
www.ti.com
5-Feb-2007
PACKAGING INFORMATION
Orderable Device
TSC2005IYZLR
TSC2005IYZLT
Status (1)
ACTIVE
ACTIVE
Package Package
Pins Package Eco Plan (2) Lead/Ball Finish MSL Peak Temp (3)
Qty
Type
Drawing
DSBGA
YZL
28
3000 Green (RoHS &
no Sb/Br)
SNAGCU
Level-1-260C-UNLIM
DSBGA
YZL
28
250 Green (RoHS &
no Sb/Br)
SNAGCU
Level-1-260C-UNLIM
(1) The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in
a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check
http://www.ti.com/productcontent for the latest availability information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements
for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered
at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and
package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS
compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame
retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material)
(3)
MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder
temperature.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is
provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the
accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take
reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on
incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited
information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI
to Customer on an annual basis.
Addendum-Page 1
IMPORTANT NOTICE
Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements,
improvements, and other changes to its products and services at any time and to discontinue any product or service without notice.
Customers should obtain the latest relevant information before placing orders and should verify that such information is current and
complete. All products are sold subject to TI’s terms and conditions of sale supplied at the time of order acknowledgment.
TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TI’s
standard warranty. Testing and other quality control techniques are used to the extent TI deems necessary to support this
warranty. Except where mandated by government requirements, testing of all parameters of each product is not necessarily
performed.
TI assumes no liability for applications assistance or customer product design. Customers are responsible for their products and
applications using TI components. To minimize the risks associated with customer products and applications, customers should
provide adequate design and operating safeguards.
TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right, copyright, mask
work right, or other TI intellectual property right relating to any combination, machine, or process in which TI products or services
are used. Information published by TI regarding third-party products or services does not constitute a license from TI to use such
products or services or a warranty or endorsement thereof. Use of such information may require a license from a third party under
the patents or other intellectual property of the third party, or a license from TI under the patents or other intellectual property of TI.
Reproduction of information in TI data books or data sheets is permissible only if reproduction is without alteration and is
accompanied by all associated warranties, conditions, limitations, and notices. Reproduction of this information with alteration is an
unfair and deceptive business practice. TI is not responsible or liable for such altered documentation.
Resale of TI products or services with statements different from or beyond the parameters stated by TI for that product or service
voids all express and any implied warranties for the associated TI product or service and is an unfair and deceptive business
practice. TI is not responsible or liable for any such statements.
TI products are not authorized for use in safety-critical applications (such as life support) where a failure of the TI product would
reasonably be expected to cause severe personal injury or death, unless officers of the parties have executed an agreement
specifically governing such use. Buyers represent that they have all necessary expertise in the safety and regulatory ramifications
of their applications, and acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related
requirements concerning their products and any use of TI products in such safety-critical applications, notwithstanding any
applications-related information or support that may be provided by TI. Further, Buyers must fully indemnify TI and its
representatives against any damages arising out of the use of TI products in such safety-critical applications.
TI products are neither designed nor intended for use in military/aerospace applications or environments unless the TI products are
specifically designated by TI as military-grade or "enhanced plastic." Only products designated by TI as military-grade meet military
specifications. Buyers acknowledge and agree that any such use of TI products which TI has not designated as military-grade is
solely at the Buyer's risk, and that they are solely responsible for compliance with all legal and regulatory requirements in
connection with such use.
TI products are neither designed nor intended for use in automotive applications or environments unless the specific TI products
are designated by TI as compliant with ISO/TS 16949 requirements. Buyers acknowledge and agree that, if they use any
non-designated products in automotive applications, TI will not be responsible for any failure to meet such requirements.
Following are URLs where you can obtain information on other Texas Instruments products and application solutions:
Products
Amplifiers
Data Converters
DSP
Applications
Audio
amplifier.ti.com
dataconverter.ti.com
dsp.ti.com
www.ti.com/audio
Automotive
Broadband
Digital Control
Military
www.ti.com/automotive
www.ti.com/broadband
www.ti.com/digitalcontrol
www.ti.com/military
Interface
interface.ti.com
logic.ti.com
Logic
Power Mgmt
Microcontrollers
RFID
power.ti.com
Optical Networking
Security
www.ti.com/opticalnetwork
www.ti.com/security
www.ti.com/telephony
www.ti.com/video
microcontroller.ti.com
www.ti-rfid.com
www.ti.com/lpw
Telephony
Low Power
Wireless
Video & Imaging
Wireless
www.ti.com/wireless
Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265
Copyright © 2007, Texas Instruments Incorporated
相关型号：
TSC2006
1.2V to 3.6V, 12-Bit, Nanopower, 4-Wire TOUCH SCREEN CONTROLLER with SPI⑩ InterfaceWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
TI
TSC2006I
1.2V to 3.6V, 12-Bit, Nanopower, 4-Wire TOUCH SCREEN CONTROLLER with SPI⑩ InterfaceWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
TI
TSC2006IRTJR
1.2V to 3.6V, 12-Bit, Nanopower, 4-Wire TOUCH SCREEN CONTROLLER with SPI⑩ InterfaceWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
TI
TSC2006IRTJT
1.2V to 3.6V, 12-Bit, Nanopower, 4-Wire TOUCH SCREEN CONTROLLER with SPI⑩ InterfaceWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
TI
TSC2007
1.2V to 3.6V, 12-Bit, Nanopower, 4-Wire Micro TOUCH SCREEN CONTROLLER with I2C InterfaceWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
BB
TSC2007
1.2V to 3.6V, 12-Bit, Nanopower, 4-Wire Micro TOUCH SCREEN CONTROLLER with I2C⑩ InterfaceWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
TI
TSC2007-Q1
1.2V to 3.6V, 12-Bit, Nanopower, 4-Wire Micro TOUCH SCREEN CONTROLLER with I2C⢠InterfaceWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
TI
TSC2007I
1.2V to 3.6V, 12-Bit, Nanopower, 4-Wire Micro TOUCH SCREEN CONTROLLER with I2C InterfaceWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
BB
TSC2007I
1.2V to 3.6V, 12-Bit, Nanopower, 4-Wire Micro TOUCH SCREEN CONTROLLER with I2C InterfaceWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
TI
TSC2007IPW
1.2V to 3.6V, 12-Bit, Nanopower, 4-Wire Micro TOUCH SCREEN CONTROLLER with I2C InterfaceWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
BB
TSC2007IPW
1.2V to 3.6V, 12-Bit, Nanopower, 4-Wire Micro TOUCH SCREEN CONTROLLER with I2C⑩ InterfaceWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
TI
TSC2007IPWG4
1.2V to 3.6V, 12-Bit, Nanopower, 4-Wire Micro TOUCH SCREEN CONTROLLER with I2C InterfaceWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
BB
©2020 ICPDF网 联系我们和版权申明