RFM68CW-915S2 [HOPERF]
Low Cost ISM Transmitter Module;
| 型号： | RFM68CW-915S2 |
| 厂家： | 
HOPERF |
| 描述： | Low Cost ISM Transmitter Module ISM频段 |
| 文件： | 总20页 (文件大小：806K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
RFM68CW
RFM68CW Low Cost ISM Transmitter Module
V1.1
Features
GENERAL DESCRIPTION
APPLICATIONS
RFM68CW
The RFM68CW is an
Garage Door Openers
Low-Cost Consumer
Electronic Applications
Remote Keyless Entry (RKE)
Remote Control / Security
Systems
ultra-low-cost,
FSK or OOK
transmitter module suitable for
operation in the 315, 433, 868 and
915 MHz licence free ISM bands.,
may be used
the RFM68CW
without the requirement for
configuration via
an MCU.
However, in conjunction with a
microcontroller, the
communication link parameters
may be re-configured. Including,
output power, modulation format
and operating channel.
KEY PRODUCT FEATURES
+10 dBm or 0 dBm
The RFM68CW offers integrated
radio performance with cost
efficiency and is suited for
operation in North America FCC
part 15.231, FCC part 15.247
DTS and FHSS modes,15.249,
and Europe EN 300 220.
Configurable output power
Bit rates up to 100 kbps
OOK and FSK modulation.
1.8 to 3.7 V supply range.
Low BOM Fully Integrated Tx
Fractional-N PLL with 1.5 kHz
typical step
In order to better use RFM68CW
modules, this specification also
Frequency agility for FHSS
modulation
involves a large number of the
parameters and functions of its
core chip RF68's,including those
IC pins which are not leaded out.
All of these can help customers
gain a better understanding of
FCC Part 15.247 DTS Mode
compliant
Module Size:16X16mm
the performance of RFM68CW
modules, and enhance the
application skills.
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RFM68CW
Table of contents
Section
Page
1.
Circuit Description....................................................................................................................................................
3
3
3
4
5
5
5
5
6
7
1.1. General Description .........................................................................................................................................
1.2. Block Diagram..................................................................................................................................................
1.3. Pin Description,............................................................................................................................................
Electrical Characteristics .........................................................................................................................................
2.1. ESD Notice ......................................................................................................................................................
2.2. Absolute Maximum Ratings .............................................................................................................................
2.3. Operating Range..............................................................................................................................................
2.4. Electrical Specifications.......................................................................................................................................
Timing Characteristics .............................................................................................................................................
2.
3.
4.
Application Modes of the RFM68CW.........................................................................................................................
8
4.1. Transmitter Modes...........................................................................................................................................
4.2. Mode Selection Flowchart................................................................................................................................
8
9
4.3. Application Mode: Power & Go ....................................................................................................................... 10
4.4. Application Mode: Advanced ......................................................................................................................... 10
4.4.1. Advanced Mode: Configuration............................................................................................................... 10
4.4.2. Frequency Hopping Spread Spectrum.................................................................................................... 10
4.5. Frequency Band Coverage ............................................................................................................................ 11
4.6. Power Consumption.........................................................................................................................................11
RFM68CW Configuration.........................................................................................................................................12
5.1. TWI Access......................................................................................................................................................12
5.2. APPLICATION Configuration Parameters ..................................................................................................... 14
5.3. FREQUENCY Configuration Parameters ...................................................................................................... 14
5.4. Test Parameters (internal) ............................................................................................................................. 15
5.5. Status Parameters ......................................................................................................................................... 15
5.6. Recovery Command ....................................................................................................................................... 16
Application Information .......................................................................................................................................... 17
6.1. Reference Design .......................................................................................................................................... 17
6.2. NRESET Pin ................................................................................................................................................... 18
6.3. TX_READY Pin............................................................................................................................................... 18
6.4. Low Power Optimization ................................................................................................................................. 18
6.4.1. 2 Connections: CTRL, DATA................................................................................................................... 18
6.4.2. 3 Connections: CTRL, DATA, TX_READY.............................................................................................. 18
RFM68CW Packaging ..............................................................................................................................................19
7.1. S2 Package Outline Drawing ...........................................................................................................................19
Ordering Information………………………………………………………………………………………………………….20
5.
6.
7.
8.
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RFM68CW
This product datasheet contains a detailed description of the RFM68CW performance and functionality.
1. Circuit Description
1.1. General Description
The RFM68CW is a multi-band transmitter module capable of FSK and OOK modulation of an input data stream.
It contains a frequency synthesizer which is a fractional-N sigma-delta PLL. For frequency modulation (FSK), the
modulation is made inside the PLL bandwidth. For amplitude modulation (OOK), the modulation is performed by turning on
and off the output PA.
The Power Amplifier (PA), connected to the RFOUT pin, can deliver 0 dBm or +10 dBm in a 50 Ω load. Each of these two
output powers need a specific matching network when efficiency needs to be optimized.
The circuit can be configured via a simplified TWI interface, constituted of pin CTRL and DATA. The pins of this interface
are also used to transmit the modulating data to the module.
Another key feature of the RFM68CW is its low current consumption in Transmit and Sleep modes and its wide voltage
operating range from 1.8 V to 3.7 V. This makes the RFM68CW suitable for low-cost battery chemistries or energy
harvesting applications.
1.2. Block Diagram
The figure below shows the simplified block diagram of the RFM68CW
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RFM68CW
1.3. Pin Description
Table 1 Description of the RFM68CW
Pin Diagram (TOP)
Pin Description
Number
Name
Type
Description
Transmitter RF Output
1
ANT
O
2
GND
GND
I
I
Exposed Pad, Ground
3
Exposed Pad, Ground
Power Supply 1.8V to 3.7V
4
VCC
I
5
GND
I
Exposed Pad, Ground
Transmit or Configuration Data
I/O
O
6
DATA
TX_READY
NC
Transmitter Ready Flag (Optional, can be left floating)
7
8
Connect to GND
-
Config Selection Configuration Data Clock
9
CTRL
NRESET
NC
I
Reset (Optional, can be left floating)
10
11
12
13
14
I
Connect to GND
-
GND
I
Exposed Pad, Ground
Exposed Pad, Ground
Exposed Pad, Ground
GND
I
I
GND
4
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RFM68CW
2. Electrical Characteristics
2.1. ESD Notice
The RFM68CW is an electrostatic discharge sensitive device. It satisfies Class 2 of the JEDEC standard
JESD22-A114-B (human body model) on all pins.
2.2. Absolute Maximum Ratings
Stresses above the values listed below may cause permanent device failure. Exposure to absolute maximum ratings for
extended periods may affect device reliability.
Table 2 Absolute Maximum Ratings
Symbol
Description
Min
Max
Unit
VDDmr
Tmr
Supply Voltage
-0.5
-55
-55
-55
3.9
115
125
150
V
Temperature
° C
° C
° C
Tjunc
Tstor
Junction Temperature
Storage Temperature
2.3. Operating Range
Operating ranges define the limits for functional operation and the parametric characteristics of the device as described in
this section. Functionality outside these limits is not implied.
Table 3 Operating Range
Symbol
Description
Min
Max
Unit
VDDop
Top
Supply voltage
1.8
-40
-
3.7
85
25
V
Operational temperature range
Load capacitance on digital ports
° C
pF
Clop
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RFM68CW
2.4. Electrical Specifications
The table below gives the electrical specifications of the transmitter under the following conditions: Supply voltage = 3.3 V,
temperature = 25 °C, fXOSC = 26 MHz, fRF = 915 MHz, 2-FSK modulation with Fdev=+/-10 kHz, bit rate = 10 kbit/s and
output power = +10 dBm terminated in a matched 50 Ohm impedance, unless otherwise specified.
Table 4 Transmitter Specifications
Symbol
Description
Conditions
Min
Typ
Max
Unit
Current Consumption
IDDSL
Supply current in Sleep mode
-
0.5
1
µA
IDDT_315 Supply current in Transmit mode
at 315 MHz*
RFOP=+10dBm 50% OOK
-
-
-
11
15
9
-
-
-
mA
mA
mA
RFOP=+10dBm FSK
RFOP=0dBm FSK
IDDT_915 Supply current in Transmit mode
at 915 MHz*
RFOP=+10dBm FSK
-
-
17.5
10.5
-
-
mA
mA
RFOP=0dBm
FSK
RF and Baseband Specifications
FBAND
Band0,For 315MHz Module
Band0,For 433MHz Module
Band0,For 868MHz Module
Band1,For 915MHz Module
312
380
380
450
MHz
MHz
MHz
Operation Frequency Bands
860
902
10
870
928
200
MHz
kHz
FDA
Frequency deviation, FSK
Bit rate, FSK
-
-
BRF
Permissible Range
Permissible Range
0.5
0.5
-
100
10
-
kbps
kbps
dB
BRO
Bit rate, OOK
-
OOK_B
RFOP
OOK Modulation Depth
45
RF output power in 50 Ohms
in either frequency band
High Power Setting
Low Power Setting*
7
-3
10
0
-
-
dBm
dBm
RFOPFL
DRFOPV
RF output power flatness
From 315 to 380 MHz, 50 Ohms load
-
2
-
dB
Variation in RF output power with
supply voltage
2.5 V to 3.3 V
1.8 V to 3.7 V
-
-
-
-
3
7
dB
dB
PHN
Transmitter phase noise
At offset:
100 kHz
350 kHz
550 kHz
1.15 MHz
-
-
-
-
-82
-92
-96
-76
-81
-91
dBc/Hz
dBc/Hz
dBc/Hz
dBc/Hz
-103
-101
STEP_22
STEP_26
RF frequency step
RF frequency step
FXOSC = 24 MHz,for 315MHz module
-
-
1.46484
1.58691
-
-
kHz
kHz
FXOSC = 26MHz, for 433,868MHz
module
FXOSC = 26MHz, for 915MHz module
STEP_26
RF frequency step
3.17383
-
kHz
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RFM68CW
Symbol
Description
Conditions
Min
Typ
Max
Unit
For 315MHz Module
For 433,868,915MHz Module
Crystal Oscillator Frequency
24
26
FXOSC
MHz
MHz
DFXOSC
Frequency Variation of the XOSC
No crystal contribution
-
-
+/-25 ppm
Timing Specifications
TS_TR
Time from Sleep to Tx mode
XTAL dependant, with spec’d XTAL
315 to 390 MHz
-
-
-
650
250
200
2000 us
TS_HOP0 Channel hop time in Band 0
TS_HOP1 Channel hop time in Band 1
500
400
us
us
Maximum hop of 26 MHz***
Programmable
TOFFT
Timer from Tx data activity to
Sleep
-
-
2
20
-
-
ms
ms
RAMP
PA Ramp up and down time
-
-
20
-
-
us
T_START
Time before CTRL pin mode
selection.
Time from power on to sampling of
CTRL **
200 us
+ TS_OSC
ms
*
With different matching networks
** The oscillator startup time, TS_OSC, depends on the electrical characteristics of the crystal
*** From the last CTRL falling edge of the Frequency change instruction to transmitter ready (PA ramp up finished)
3. Timing Characteristics
The following table gives the operating specifications for the TWI interface of the RFM68CW.
Table 5 Serial Interface Timing Specifications
Symbol Description
Conditions
Min
-
Typ
Max
Unit
MHz
ns
f
t
t
t
t
t
CTRL Clock Frequency
CTRL Clock High time
CTRL Clock Low time
CTRL Clock rise time
CTRL Clock Fall time
-
-
-
-
-
-
10
-
CTRL
ch
45
45
-
-
ns
cl
5
5
-
ns
rise
fall
-
ns
From Data transition to CTRL rising
edge
45
ns
setup
DATA Setup time
DATA hold time
t
From CTRL rising edge to DATA
transition
45
-
-
-
-
-
5
-
ns
us
us
hold
t0, t
Time at “1” on DATA during
Recovery command
See Figure 9 and Figure 10
2
t
Time at “0” on DATA during
Recovery command
See Figure 10
5
1
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RFM68CW
4. Application Modes of the RFM68CW
Pins CTRL and DATA are used for both configuring the circuit and sending the data to be transmitted over the air. Two
different modes are associated to these pins, “Power&Go” and “Advanced” modes.
4.1. Transmitter Modes
Automatic Mode operation is described in Figure 2. Here we see that a rising edge on the DATA pin activates the
transmitter start-up process. DATA must be held high for the start-up time (TS_TR) of the RFM68CW. During this time the
RFM68CW undergoes an optimized, self-calibrating trajectory from Sleep mode to Transmit mode. Once this time has
elapsed, the RFM68CW is ready to transmit. Any logical signal subsequently applied to the DATA pin is then transmitted.
Figure 2.
‘Power & Go’ Mode: Transmitter Timing Operation
The transition back to Sleep mode is managed automatically. The RFM68CW waits for TOFFT (2 or 20 ms) of inactivity on
DATA before returning to Sleep mode.
In Forced Transmit Mode the circuit can be forced to wake up and go to TX mode by sending an APPLICATION
instruction through the TWI interface, and setting the Mode bit DA(15) to ‘1’. Once in Transmit the circuit will transmit over
the air the data stream presented on the DATA pin. The circuit will stay in transmit mode until a new APPLICATION
instruction is sent with DA(15) to ‘0’.
Figure 3.
Forced Transmit Mode
Description
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RFM68CW
4.2. Mode Selection Flowchart
Circuit Start-up
Wait T_Start
Check
CTRL Pin
Logic ‘0’
Logic ‘1’
Power & Go 1
868.3 MHz
FSK, Fdev=+/-19.2kHz
+10dBm
Power & Go 2
433.92 MHz
OOK
+10dBm
CTRL Clock signal
Advanced Mode Full
register flexibility Automatic
or forced Transmit
Figure 4.
RFM68CW Mode
Selection
Note Advanced mode is entered only if DATA is held low during CTRL’s rising edge.
When powering up the circuit (microcontroller and RFM68CW), the logic level of the CTRL pin is sampled after T_START,
as described on Figure 5. During T_START, the microcontroller IO driving the CTRL pin must be configured as an output,
driving the CTRL pin to the desired state.
Figure 5.
Power-up
Timing
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RFM68CW
4.3. Application Mode: Power &Go
The default ‘Power & Go’ application mode sees the RFM68CW configured as detailed in Table 6. By changing the logical
state of the CTRL pin at Power-up or Reset, two distinct configuration modes can be selected. The Power & Go application
modes hence permit microcontroller-less operation.
Table 6 Configuration in Power & Go Mode
CTRL Pin
‘Low’
Configuration
Mode
FSK 868.3 MHz, +10 dBm, Fdev=+/-19.2 kHz
Power&Go 1
Power&Go 2
‘High’
OOK 433.92 MHz, +10 dBm
4.4. Application Mode: Advanced
4.4.1. Advanced Mode: Configuration
As described on Figure 4, Advanced mode is entered when accessing the Two Wire Interface (TWI) bus of the RFM68CW.
Upon communication to the register at up to 10 MHz of clocking speed, complete flexibility on the use of the module is
obtained.
Once all register settings are selected (see registers detailed description in section [5]), the RFM68CW can be used either
in
Automatic mode by simply toggling the DATA pin, or in Forced Transmit mode to optimize timings for instance.
4.4.2. Frequency Hopping Spread Spectrum
Frequency hopping is supported in Advanced mode. After sending the data stream in the first channel, the user can send
a Frequency change instruction containing the new channel frequency. The circuit will automatically ramp down the PA,
lock the PLL to the new frequency, and turn the Power Amplifier back on. The user can then send his packet data on the
new channel. Timings are detailed hereafter:
t < TOFFT
TWI
t < TOFFT
(2 or 20 ms)
instruction
(2 or 20 ms)
Frequencychange
Frequencychange
DATA
CTRL
RFOUT
5th falling
edge on CTRL
24th falling
edge on CTRL
TS_HOPi
Tx Channel
A
Tx Channel
B
Figure 6.
Frequency Hopping Description
Notes
- During any TWI access, the input of the modulator is inhibited
- The time between two Frequency change instructions shall be greater than TS_HOPi
- FHSS modulation, as described under FCC part 15.247, is supported by the RFM68CW; also note that the
large Frequency Deviation settings available on the RFM68CW make it suitable for “Digitally Modulated
Systems”, as described under FCC Part 15.247 (a)(2)
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RFM68CW
4.5. Frequency Band Coverage
The RFM68CW offers several combinations or frequency references and frequency outputs, allowing for maximum
flexibility and design of multi-band products:
Table 7 Frequency Selection Table
Reference
Frequency
FXOSC
Upper / Lower
Frequency
Bounds
Band Setting
DA(13)
Frf &
Fdev
Fstep
22x106
-----------------
214
Fstep=
Fstep=
= 1.34277kHz
= 1.46484kHz
22 MHz
24 MHz
310 to 450 MHz
312 to 450 MHz
338 to 450 MHz
24x106
-----------------
0
214
Frf= DF(18;0) × Fstep
Fdev= DA(12;5) × Fstep
26x106
-----------------
Fstep=
Fstep=
= 1.58691kHz
214
26 MHz
6
860 to 870 MHz
and
902 to 928 MHz
26x10
-----------------
213
= 3.17383kHz
1
4.6. Power Consumption
The following typical power consumption figures are observed on the RFM68CW kits. Note that the transmitter efficiency
depends on the impedance matching quality, and can be PCB design dependant.
The PA matching may be different in each frequency band.
Table 8 Power Consumption in Tx mode
Typical Current
Frequency Band
Conditions
Drain
310 to 450 MHz
Pout=+10dBm, OOK modulation with 50% duty cycle
Pout=+10dBm, FSK modulation
Pout=0dBm, FSK modulation
11 mA
15 mA
9 mA
860 to 870 MHz
902 to 928 MHz
Pout=+10dBm, FSK modulation
Pout=0dBm, FSK modulation
16.5 mA
10 mA
Pout=+10dBm, FSK modulation
Pout=0dBm, FSK modulation
17.5 mA
10.5 mA
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RFM68CW
5. RFM68CW Configuration
The RFM68CW has several configuration parameters which can be selected through the serial
interface
5.1. TWI Access
As long as CTRL is kept stable, the DATA pin is considered by the circuit as the input for the data to be transmitted over the
air (Power&Go modes).
Programming of the configuration register is triggered by a rising edge on the CTRL line. Upon detection of this rising edge,
the data applied to the DATA pin is accepted as register configuration information, the data bits are clocked on subsequent
rising edges of the clocking signal applied to the CTRL pin. The timing for RFM68CW configuration register ‘write’ is shown
in Figure 7. Note that, once triggered, all 24 clock cycle must be issued to the RFM68CW.
CTRL
DATA
1st
2nd
23rd
24th
DATA pin is an input
Figure 7.
TWI Configuration Register ‘Write’.
The registers may, similarly, be read using the timing of Figure 8.
CTRL
DATA
1st 2nd
8th
24th
DATA pin is an output
DATA pin is an input
Figure 8.
TWI Configuration Register ‘Read’.
The first rising edge on CTRL which initiates the ADVANCED mode must occur at least 1 ms after the circuit has been
powered up or reset.
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RFM68CW
Table 9 TWI Instruction Table
Byte 0
Byte 1
Byte 2
Instruction
7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0
0 0 0 0
0 0 0 1 1
0 0 1 0
0 0 1 1
0 1 0 0
0 1 0 1
(0000)
DA(15:0)
DF(18:0)
Write Application bits
Write Frequency bits
(0)(0010)(0010)
DT(10:0)
Write Test bits (pad protected)
Read Application bits
(0011)
(0100)
(0101)
DA(15:0)
DF(15:0)
Read the 16 least significant Frequency bits
DS(12:5)
DS(4:0)
DF(18: Read Chip version, Status and 3 most significant
16)
Frequency bits
0 1 1 0
0 1 1 1
1
(0110)
(0111)
DS(28:13)
DT(10:0)
Read Bist signature
Read Test bits
(1111)(1)
x
Discarded, not an instruction
Recovery instruction
All 1
Notes
- The first “0” transmitted to the RFM68CW is required to initialize communication
- The following 3 bits (highlighted in blue) determine the type of instruction
- The forthcoming bits (highlighted in green) define a protection pattern; any error in these bits voids the instruction
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RFM68CW
5.2. APPLICATION Configuration Parameters
Power
&Go 1
Power
&Go 2
Name
Mode
Number
Description
DA(15)
0
Mode:
0 → Automatic mode
1 → Forced transmit mode
Modul
DA(14)
0
1
1
Modulation scheme:
0 → FSK
1 → OOK
Band
Fdev
DA(13)
0
Band 0, 310 to 450 MHz
Band 1, 860 to 870 MHz and 902 to 928 MHz
DA(12:5)
0x06
Fdev=
+/-19.2kHz
Unused
RF Frequency deviation in FSK mode only
See Table 7 for details
Pout
DA(4)
DA(3)
1
1
1
Output power range:
0 → 0 dBm
1 → 10 dBm
TOFFT
0
Period of inactivity on DATA before
RFM68CW enters Sleep mode in Automatic
mode:
0 → 2 ms
RES
DA(2:0)
100
100
Reserved
Table 10 APPLICATION Configuration Parameters
Note All changes to the APPLICATION parameters must be performed when the device is in Sleep mode, with the
exception of DA(15). Mode can be sequentially written to “1”, and then “0” while the device is in Transmit mode, to
speed up the turn off process and circumvent the TOFFT delay.
5.3. FREQUENCY Configuration Parameters
Power
&Go 1
Power
&Go 2
Name
Frf
Number
Description
DF(18:0)
0x42CAD
0x42C1C
RF operating frequency
Frf=868.3 MHz
With 26 MHz
reference
Frf=433.92 MHz
With 26 MHz
reference
See Table 7 for details
Table 11 FREQUENCY Configuration Parameters
If done in Sleep mode, the Frequency change instruction will be applied next time the RFM68CW is turned on. If
Frequency change occurs during transmission, the automated Frequency Hopping sequence described in section [4.4.2]
will take place.
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RFM68CW
5.4. Test Parameters (internal)
Ten Test bits DT(9:0) exist in the RFM68CW. They are only use for the industrial test of the device, and therefore they are
pad protected. It means that their value cannot be modified without applying a specific logical level to some of the
RFM68CW pads during a write access.
5.5. Status Parameters
DS(12:5) are read-only bits, organized as follows:
Default
Advanced
Mode
Power
&Go 1
Power
&Go 2
Name
Number
Description
RES
DS(28:13)
DS(12:5)
-
Reserved
“0001 0001” --> V1A
Chip
Chip identification number
Version
RES
DS(4:0)
-
Reserved
Table 12 Status Read-Only Parameters
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RFM68CW
5.6. Recovery Command
In the event of spurious activity (less than 24 clock cycles received) on the CTRL pin, control over the TWI interface can be
recovered in two possible ways:
t2
Recovery Command
DATA
CTRL
1st rising
24th rising
edge on CTRL
edge on CTRL
Figure 9.
Quick Recovery Command
t1
t0
DATA
CTRL
1st rising edge
24th rising edge
Figure 10.
Pulsed Recovery Command
Notes
- If t2 < 5 us, the RFM68CW will not turn into Tx mode during the recovery command (if not previously in Tx mode)
- If t1 < 5 us, with t0 > 5 us, the RFM68CW will not turn into Tx mode in the second scenario of recovery command
- During the Pulsed recovery command, t0 timing does not have any upper limit
- If t1 or t2 exceeds 5us, the recovery command will still be successful, but the transmitter will momentarily turn on
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RFM68CW
6. Application Information
6.1. Reference Design
Figure 11:Typical Application Schematic
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RFM68CW
6.2. NRESET Pin
When required, the pin NRESET can be controlled externally, to allow for:
either a delayed Power On Reset (POR) cycle of the RFM68CW, allowing for the companion micro to reset and
assign its
port directions. This is achieved by connecting a R/C time constant to the NRESET pin.
or an On-the-go Reset of the RFM68CW at any moment in time, if required by the application. This is achieved by
pulling
the NRESET pin low for more than 100 microseconds, then releasing it to high impedance (normal termination).
6.3. TX_READY Pin
For timing critical applications, TX_READY pin can be useful to know precisely when the transmitter is ready for operation,
and therefore save energy. To this end, TX_READY can optionally be connected to inform the companion device that the
PA ramp up phase has been terminated, hence the RFM68CW is ready for data transmission.
6.4. Low Power Optimization
The RFM68CW is designed to reduce the cost of the RF transmitter functionnality. To this end, a single DATA signal can
be enough to operate the transmitter, in any of the two Power & Go modes. In this situation, TS_START and TOFFT
timings, tabulated in Section 2.4, must be respected, leading to significant periods of time during which the transmitter is On
and no valuable information is transmitted.
For more demanding applications where energy usage is critical, the RFM68CW offers hardware and software support to
accurately control the transmitter On time, and therefore save energy:
6.4.1. 2 Connections: CTRL, DATA
If the two signals of the TWI interface can be controlled by the host microcontroller, Tx On time can be accurately controlled
as follows:
At the device turn on, instead of waiting for TS_TR (2ms max, but very XTAL dependant), the status flag
TX_READY
can be polled on the TWI interface. As soon as the TX_READY flag is set, the microcontroller can start toggling DATA
to transmit the useful packet. This method is valid in both Forced Tx and Automatic modes.
At the device turn off, instead of waiting for TOFFT (2 or 20ms), the user can immediately turn off the transmitter
after
the transmission of packet, assuming that the Forced Transmit mode was selected.
6.4.2. 3 Connections: CTRL, DATA, TX_READY
In applications where the number of connections between the microcontroller and the RF module is less critical,
TX_READY pin can be connected to either a GPIO port, or an external interrupt port of the micro. The two optimizations
described in the former subsection will also be possibl
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RFM68CW
7. Packaging Information
7.1. S2 Package Outline Drawing
Figure 12: S2 Package Outline Drawing
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RFM68CW
8. Ordering Information
RFM68CW —433 S2
Package
Operation Band
Mode Type
P/N: RFM68CW-315S2
RFM68CW module at 315MHz band, SMD Package
P/N: RFM68CW-433S2
RFM68CW module at 433MHz band, SMD Package
P/N: RFM68CW-868S2
RFM68CW module at 868MHz band, SMD Package
P/N: RFM68CW-915S2
RFM68CW module at 915MHz band, SMD Package
This document may contain preliminary information and is subject to
change by Hope Microelectronics without notice. Hope Microelectronics
assumes no responsibility or liability for any use of the information
contained herein. Nothing in this document shall operate as an express or
implied license or indemnity under the intellectual property rights of Hope
Microelectronics or third parties. The products described in this document
are not intended for use in implantation or other direct life support
applications where malfunction may result in the direct physical harm or
injury to persons. NO WARRANTIES OF ANY KIND, INCLUDING, BUT
NOT LIMITED TO, THE IMPLIED WARRANTIES OF MECHANTABILITY
OR FITNESS FOR A ARTICULAR PURPOSE, ARE OFFERED IN THIS
DOCUMENT.
HOPE MICROELECTRONICS CO.,LTD
Add: 2/F, Building 3, Pingshan Private
Enterprise Science and Technology
Park, Lishan Road, XiLi Town,
Nanshan District, Shenzhen,
Guangdong, China
Tel: 86-755-82973805
Fax: 86-755-82973550
Email:
sales@hoperf.com
Website: http://www.hoperf.com
http://www.hoperf.cn
©2006, HOPE MICROELECTRONICS CO.,LTD. All rights reserved.
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