B14SC04-R_技术文档

4 digit 7 segment LED displays with Cascadable Serial driver

______________________________________________________

B14SC04

B20SC04

B25SC04

B38SC04

General Description

The B14SCM04, B20SC04, B25SC04 and B38SC04 displays are 4 digit seven segment LED

displays combined with an 8 digit, multiplexed drive, integrated circuit with a cascadable serial

interface. Four digits are mounted with the driver on to the PCB which also has connections for

the BM multiplexed display family allowing expansion to 8 digits. The devices are available in

high efficiency red, green and yellow colour variants. Each of the standard displays has a right

hand decimal point in each digit. LED sizes include 14mm (0.56inch), 20mm (0.8inch) 25mm

(1inch) and 38mm (1.5inch) display areas.

The on board driver chip has a serial input format that features serial data, clock and chip enable.

A single 5 volt supply is required. The serial bus signals interface is HCMOS levels and the

format is compatible with SPI, QSPI and MICROWIRE. It features slew rate limiting for

reduced EMI. Included on chip is a BCD code B decoder and digit ram. An undedecoded mode

is also available. The chip can be programmed to display from 1 to 8 digits using the scan limit

register. Only one external resistor is required to set the maximum brightness that can then be

digitally dimmed in 16 levels. A test mode forces all LED’s on. Low power shutdown reduces

current to 150uA.

Configuration

Dimensions

Dim

(mm)

A

B14

58.5

2.54

14.0

37.0

51.5

B20

75.0

2.54

20.0

38.0

68.5

18.0

B25

97.0

2.54

25.0

44.0

90.0

18.0

B38

121.0

2.54

38.0

54.0

115.5

18.0

B

C

D

E

Depth 16.0

Pinout

1

3

5

7

9

11

13

15

17

19

+5V

2

CS CLK

DIN DOUT 0V

0V

SEGA

SEGB

10

SEGC

SEGD

12

SEGE SEGG DIG1 DIG3

SEGF SEGDP DIG2 DIG4

4

6

8

14

16

18

20

Nexus Machines Ltd reserves the right to alter or withdraw the product specification and characteristics without prior notice at any time in line

with product development. Nexus Machines Ltd sole and exclusive warranty is that stated in the warranty article of the conditions of sale.

Although every effort is made to ensure this data is accurate no liability is accepted for errors or omissions that may affect the end product.

Week0802

- 1 -

Electrical Characteristics

Parameter

Supply voltage

Min

4.0

Typ

5.0

Max

5.5

Units

V

Conditions

Shutdown supply current

Power supply current

Display scan rate

Input voltage logic 0 (VL)

Input voltage logic 1 (VH)

150

uA

mA

Hz

V

All leds off

All segs on

8 digits scanned

Vcc=5.0 volts

330

800

500

-0.3

3.5

1300

0.8

V

Segment drive current(seg

off)

1

uA

Segment drive current(seg on) -30

Segment matching

Output sink current (digit off)

Output sink current (digit on) 320

-40

3

-45

10

mA

%

uA

mA

ns

Vdig=10 volts

Vout=0.65

tr = tf = 20ns

Clock High time

Clock Low time

Clock period

CS fall to SCLK rise setup

Clk rise to CS rise hold time

Din setup time

50

100

25

0

25

0

ns

Din hold time

Output data prop delay

Load rising edge to next clk

rising edge

Minimum CS or load pulse

high time

25

ns

50

ns

Data input to seg delay

Data input hold time

2.5

300

ns

Brightness setting resistor

Operating temperature

9.53

k ohms

deg C

Vdd=5V +/- 10%

Vdd=5V 4 LED’s on

0

70

Nexus Machines Ltd reserves the right to alter or withdraw the product specification and characteristics without prior notice at any time in line

with product development. Nexus Machines Ltd sole and exclusive warranty is that stated in the warranty article of the conditions of sale.

Although every effort is made to ensure this data is accurate no liability is accepted for errors or omissions that may affect the end product.

Week0802

- 2 -

Pin Functions

+5v

Pin 1,2

+5 volts power supply to LED

Chip enable Pin 3

Chip select - this pin must be low for a data transfer to occur. he last 16 bits of serial data are

latched on CS rising edge.

Data input

Pin 4

Serial data input -data is loaded into the internal 16 bit register on the clocks rising edge.

Clock

Pin 5

Clock line - On clocks rising edge data is shifted into the internal shift register. On clocks falling

edge data is shifted out of Dout.

Data output

Pin 6

Serial data output -the data into DIN is valid at DOUT 16.5 clock cycles later. This pin is used to

daisy chain devices

0 Volts

Pin 7,8

The chip and LED’s 0 volts line.

Segments A,B,C,D,E,F,G and DP

Pins 9,10,11,12,13,14,15,16

Seven Segment drives and decimal point Drive that source current to the display

Digit 4,5,6,7 Pin 17,18,19,20

Digit lines 4 through 7 drive line that sinks current from the common cathode LED. These can

be used to drive an external 4 digit 7 segment LED display(BM series). Digit lines 0 to 3 are

connected to the “internal” display. Digit 0 is the LSB on the right hand side.

Serial Data Format (16 bits)

15 14 13 12 11 10

9

8

7

6

5

4

3

2

1

0

X

A3 A2 A1 A0 D7 D6 D5 D4 D3 D2 D1 D0

Nexus Machines Ltd reserves the right to alter or withdraw the product specification and characteristics without prior notice at any time in line

with product development. Nexus Machines Ltd sole and exclusive warranty is that stated in the warranty article of the conditions of sale.

Although every effort is made to ensure this data is accurate no liability is accepted for errors or omissions that may affect the end product.

Week0802

- 3 -

Register Address Map

Register

No operation

Digit 0

Digit 1

Digit 2

Digit 3

Digit 4

Digit 5

Digit 6

D15-D12

A3

0

1

A2

0

1

0

1

A1

0

1

0

1

0

1

0

1

A0

0

1

0

1

0

1

0

1

0

1

0

1

0

1

Hex code

X0

X1

X2

X3

X4

X5

X6

X7

X8

X9

XA

XB

XC

XF

X

Digit 7

Decode mode

Intensity

Scan limit

Shutdown

Display test

Display command Register Functions

Shutdown register Format (address Xch)

Mode

Shutdown

Mode

Address D7

D6

X

D5

X

D4

X

D3

X

D2

X

D1

X

D0

0

XCh

X

Normal

Operation

XCh

X

1

Decode Mode Register: Setting this register sets BCD code (0-9,E,H,L,P and -) or no decode

operation for each digit. Each bit in the register corresponds to one digit. A logic 1 selects Code

B decoding whereas a logic 0 enables non decode mode. In decode mode bits 0-3 correspond to

the BCD data for the digit and bit D7 is the decimal point. In non decode mode data bits 0 to 7

correspond to the segment lines as outlines in the table below.

Decode Mode register examples

Decode Mode

D7

D6

D5

D4

D3

D2

D1

D0

Hex

code

00

No decode for digits 7-0

0

1

Code B decode for digit 0

and no decode for digits 7-1

Code B decode for digits 3-0

and no decode for digits 7-4

Code B decode for digits 7-0

01

0

1

0

1

0

1

0

1

0Fh

FFh

Nexus Machines Ltd reserves the right to alter or withdraw the product specification and characteristics without prior notice at any time in line

with product development. Nexus Machines Ltd sole and exclusive warranty is that stated in the warranty article of the conditions of sale.

Although every effort is made to ensure this data is accurate no liability is accepted for errors or omissions that may affect the end product.

Week0802

- 4 -

Decode Mode

7 Seg

D7

D6-D4

D3

D2

D1

D0

character

0

1

2

3

4

5

6

7

8

9

-

E

H

L

P

DP 0n =1

Dont care

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

Blank

Non Decode Mode

D7

DP

D6

A

D5

B

D4

C

D3

D

D2

E

D1

F

D0

G

Segment line

The LED current is set to a maximum value via an on board resistor. This provides the

maximum level of brightness. The LED display controller also features a facility to Digitally set

the display brigtness from the host microcontroller. This control allows the on board pulse width

modulator to control the segment current and thus the brightness.

Intensity Register Format

Duty Cycle

1/32 (min)

3/32

5/32

7/32

D7-D4

D3

0

1

D2

0

1

0

1

D1

0

1

0

1

0

1

0

1

D0

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

Hex code

X0h

X1h

X2h

X3h

X4h

X5h

X6h

X7h

Dont care

9/32

11/32

13/32

15/32

17/32

19/32

21/32

23/32

25/32

27/32

29/32

31/32

X8h

X9h

XAh

XBh

XCh

XDh

XEh

XFh

Nexus Machines Ltd reserves the right to alter or withdraw the product specification and characteristics without prior notice at any time in line

with product development. Nexus Machines Ltd sole and exclusive warranty is that stated in the warranty article of the conditions of sale.

Although every effort is made to ensure this data is accurate no liability is accepted for errors or omissions that may affect the end product.

Week0802

- 5 -

The display also features a scan limit register that sets how many digits are displayed from 1 to

8.These are displayed in a multiplexed manner with a typical display scan rate of 800Hz. Since

the number of digits displayed affects the overall display intensity the scan limit registers should

not be used to provide leading zero suppression.

WARNING: DO NOT select less than 3 scanned digits (there are 4 leds on the display so it

should be set to 4) otherwise excessive power dissipation will occur in the driver chip.

Scan Limit Register format

Scan Limit

D7-D3

D2

D1

D0

Hex

code

X0h

X1h

X2h

X3h

X4h

X5h

X6h

X7h

Digit 0

Digit 0,1

Digit 0,1,2

Digit 0,1,2,3

Digit 0,1,2,3,4

Digit 0,1,2,3,4,5

Digit 0,1,2,3,4,5,6

Digit 0,1,2,3,4,5,6,7

Dont care

0

1

0

1

0

1

0

1

0

1

0

1

0

1

Nexus Machines Ltd reserves the right to alter or withdraw the product specification and characteristics without prior notice at any time in line

with product development. Nexus Machines Ltd sole and exclusive warranty is that stated in the warranty article of the conditions of sale.

Although every effort is made to ensure this data is accurate no liability is accepted for errors or omissions that may affect the end product.

Week0802

- 6 -

LED display characteristics

The Led display provides excellent output brightness verses forward current with intensity

matching of better than 10% and a long operating life with minimal display degradation. The

LED’s on the driver PCB are termed “Internal” LED’s, whilst those that can be attached to the

driver chip via a cable (not longer than 10 inches) are termed external. Note that additional

LED displays may require greater supply decoupling. It is recommended that 10uf of capacitance

be added for every additional LED digit. A 10 volt electrolytic is suitable.

EMC: The displays are designed with slew limited drivers to ensure minimal EMC emmissions.

However the cable that is wired to the display is a large source of unwanted emissions. Care

should be taken to ensure minimal cable lengths are used where ever possible and a ferrite ring

should be added to the cable to provide additional attenuation. The LED’s draw quite a high

instantaneous current and the power supply and its wiring should be designed to carry the current

whilst providing a low impedance path. Additional capacitance may be required at the display.

The end product must be complient with the relevant criteria and the user should check that the

display is connected such that it is so.

Display LED format

Digit 7

Digit 6

Digit5

Digit 4

Digit 3

Digit 2

Digit 1

Digit 0

Ext LHS Ext LHM Ext RHM Ext RHS Int LHS

Int LHM Int RHM Int RHS

LED brightness Min/Typ (mCd)

Color

Green

HE Red

Yellow

14mm

0.9 / 2.4

20mm

25mm

38mm

1.3 / 3.6

1.4 / 3.6

1.3 / 3.2

1.0 / 2.55

1.3 / 3.3

1.4 / 3.6

1.3 / 3.2

Cascading displays: The displays are cascadable by connecting the Dout pin from the first

display to the Din pin on the next display in line. The other signals (chip enable and clock) are

common to all displays. The number of data bits remains the same for each display hence if 4

displays are cascaded then 64 bits are required to alter the displayed value ON ANY DISPLAY.

The command set allows for a NO OPERATION which leaves the addressed display with the

previous register values.

MAXIMUM RATINGS: THE USER IS DIRECTED TOWARDS THE MAXIMUM VALUES

OUTLINED IN THE ELECTRICAL CHARACTERISTICS. OPERATION OUTSIDE OF

THESE LIMITS MAY AFFECT PERMANENT DAMAGE TO THE LED DISPLAY OR THE

DRIVER CHIP.

Additional Information: The user is directed towards the Maxim Integrated Products data sheet

for the MAX7219/MAX7221 for information regarding the serial interface and further display

driver commands.

All Trade marks acknowledged.

Nexus Machines Ltd reserves the right to alter or withdraw the product specification and characteristics without prior notice at any time in line

with product development. Nexus Machines Ltd sole and exclusive warranty is that stated in the warranty article of the conditions of sale.

Although every effort is made to ensure this data is accurate no liability is accepted for errors or omissions that may affect the end product.

Week0802

- 7 -

Typical Applications

Simple 4 digit display to microcontroller interface.

Cascading LED displays

Nexus Machines Ltd reserves the right to alter or withdraw the product specification and characteristics without prior notice at any time in line

with product development. Nexus Machines Ltd sole and exclusive warranty is that stated in the warranty article of the conditions of sale.

Although every effort is made to ensure this data is accurate no liability is accepted for errors or omissions that may affect the end product.

Week0802

- 8 -

Data prepared by :

Nexus Machines Ltd

White Swan House

60 High Street

Godstone

Surrey

RH9 8LW

Email :

Web site :

Technical support:

sales@nexusmachines.com

www.nexusmachines.com

0906 558 1010

Please note that the technical support line is charged at a rate of £1 per minute.

Nexus Machines Ltd reserves the right to alter or withdraw the product specification and characteristics without prior notice at any time in line

with product development. Nexus Machines Ltd sole and exclusive warranty is that stated in the warranty article of the conditions of sale.

Although every effort is made to ensure this data is accurate no liability is accepted for errors or omissions that may affect the end product.

Week0802

- 9 -


型号：	B14SC04-R
厂家：	ETC
描述：	DISPLAY 4 DIGIT HE RED 14MM 显示4位数HE RED 14MM\n
文件：	总9页 (文件大小：295K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

B14SC04-R [ETC]

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