CXLE88142A is a special integrated circuit for LED drive control integrated with keyboard scanning interface, which is widely used in household appliances, industrial control and intelligent display devices. The chip integrates MCU digital interface, data latch, LED circuit and keyboard scanning module, which has high reliability, strong anti-interference ability and excellent stability. It is suitable for digital tube or LED display modules of smart water heaters, microwave ovens, washing machines, air conditioners, induction cookers, set-top boxes, electronic scales, smart meters and other equipment.
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[ CXLE88142A ]"
CXLE88142A LED Drive Controller: technical details and Application Guide
I. Product Overview
CXLE88142A is a special integrated circuit for LED drive control integrated with keyboard scanning interface, which is widely used in household appliances, industrial control and intelligent display devices. The chip integrates MCU digital interface, data latch, LED circuit and keyboard scanning module, which has high reliability, strong anti-interference ability and excellent stability. It is suitable for digital tube or LED display modules of smart water heaters, microwave ovens, washing machines, air conditioners, induction cookers, set-top boxes, electronic scales, smart meters and other equipment.
II. Main features
2.1. Process Technology: using CMOS technology, low power consumption and high efficiency.
2.2. Flexible display mode: supports 10-segment × 7-bit to 13-segment × 4-bit display configurations.
2.3. Keyboard scanning: supports up to 10 × 2 matrix button.
2.4. Brightness adjustment: 8-level duty cycle adjustable, supports smooth brightness adjustment.
2.5. Communication interface: three-wire serial interface (CLK, STB, DIO) for easy connection with MCU.
2.6. Built-in functions: RC oscillator, power-on reset circuit, data latch, and LED reverse bias leakage optimization circuit.
2.7. Encapsulation form: SOP28, suitable for compact PCB design.
3. Detailed explanation of pin functions
| Pin symbol | Name | Function description |
|---|---|---|
| DIO | Data input and output | Serial data communication, open-drain output, built-in pull-up |
| CLK | Clock input | Synchronous data transmission, built-in pull-up |
| STB | Chip selection input | Initialize the serial port and identify commands. |
| K1 ~ K2 | Key scan input | Button signal detection, built-in drop-down |
| SEG/KS | Segment output/key scan output | Multiplexing pin, support segment display and keyboard scanning |
| GRID | Bit output | Digital tube-bit selection control |
| VDD/GND | Power/ground | Dual Power pin design for enhanced stability |
IV. Instruction system
The first byte entered by DIN after STB failling edge is used as the instruction. After decoding, the highest bits of B7 and B are taken to distinguish different instructions.
The command or data remains valid).
CXLE88142A supports four types of instructions, which are transmitted through serial ports. The first byte of the instruction is two bits high (B7, B6) for distinguishing types:
4.1 Display mode settings(B7B6 = 00): Set the Display segment and number of digits, such as 4-digit 13-digit, 7-digit 10-digit, etc.
This command is used to set the number of selected segments and bits (4 to 7 bits, 10 to 13 segments). When the instruction is executed, the display is forcibly closed. In
When the display mode is unchanged, the data in the video memory will not be changed, and the display control command controls the Display switch. When power on, the default display mode is 7-Bit 10
Segment.
4.2. Data command settings(B7B6 = 01): configure data read/write mode and address mode.
This command is used to set data write and read. Bits B1 and B0 cannot be set to 01 or 11.
4.3. Display control commands(B7B6 = 10): control the display switch and 8-level brightness adjustment.
This command is used to set the Display switch and display brightness adjustment. A total of 8 levels of brightness are available for adjustment.
4.4. Address command settings(B7B6 = 11): sets the start address of the display register.
This command is used to set the address of the display register. The maximum valid address is 14 bits (00H-0DH). If the address is set to 0EH or higher, the data is ignored.
Slightly, until the valid address is set. When power on, the address is set to 00h by default.
V. Display register and driver mode
The chip has a built-in 14-byte display register (address C0H ~ CDH), which supports co-negative and co-Positive Digital Tube drivers.Attention: after power-on, clear operation of the video memory is required to avoid garbled codes.
5.1. Co-Yin digital tube: SEG is connected to the anode, GRID is connected to the cathode, and data is directly written to the corresponding address.
Figure 7 shows the connection diagram of common cathode digital tube. If the digital tube is displayed as "0", you only need to open it from the low position to the 00H(GRID1) address.
Start writing 0x3F data. At this time, the data corresponding to each SEG1-SEG8 is as follows.
Figure 8 shows the connection diagram of common anode digital tube. If you let the digital tube display "0", you need to address units C0H(GRID1), C2H(GRID2),
In C4H(GRID3), C6H(GRID4), C8H(GRID5), CAH(GRID6), the data is written for 01h respectively, and the remaining addresses 0CH(GRID7) are all written.
According to 00h. The data corresponding to each SEG1-SEG8 is shown in the following table.
▲Note: whether driving the common cathode digital tube or driving the common anode digital tube, SEG pin can only be connected to the LED anode, GRID can only be connected to the LED cathode, no
It can be connected in reverse.
5.2. Gongyang digital tube: write data to multiple GRID addresses, and note that SEG and GRID cannot be reversed.
5.3. Display register address:
This register stores data transmitted from external devices to CXLE88142A through the serial interface. The maximum valid address is 14 bytes from 00H-0DH,
Corresponding to the SEG and GRID pins of the chip respectively, the specific allocation is shown in figure (2):
When writing LED display data, the data bytes are operated from low to high according to the display address.
▲Note: the value stored in the chip display register at the moment of power-on may be randomly uncertain. At this time, the customer directly sends the Open Screen command,
Garbled codes may appear. Therefore, we recommend that the customer power on the display register for clear operation at a time, that is, the 14-bit memory address after power-on.
0x 00 is written to all data in (C0H-CDH).
VI. Keyboard scanning function
CXLE88142A supports 10 × 2 matrix button scanning to automatically complete the scanning process. Users only need to read 5 bytes of key-value data in sequence. Key-value data is mapped by BIT BIT, which supports multi-key detection and anti-shake processing.
6.1. The maximum key scan matrix supported by the chip is 10 × 2 bits, as shown in the following figure:
The key scan data storage address is as follows. After the read button command is sent first, the 5-byte button data BYTE1-BYTE5 is started to be read, and the read data is opened from the low point.
The initial output, where the B7 and B6 bits are invalid and the fixed output is 0. When the button corresponding to the K and KS pins of the chip is pressed, the BIT in the corresponding byte is 1.
▲Note:1. CXLE88142A can read up to 5 bytes and cannot read more.
2. Read data bytes can only be read from BYTE1-BYTE5 in sequence and cannot be read across bytes. For example, K2 and KS10 on hardware correspond to button
To read this button data, you must read the 5th bit of the fifth byte before reading the data.
3. Reading key values across bytes is not supported;
4. It is recommended to design the composite button on different k lines to avoid signal conflicts.
6.2. Button:
6.2.1) button scan:The key scan is automatically completed by CXLE88142A and is not controlled by the user. The user only needs to read button values according to the time series. Complete a key scan
Two display cycles are required. A display cycle takes about T = 4ms. Two different button are pressed in 8ms. The key values read twice are pressed first.
The key value of Button.
In the 7-Bit 10-segment mode, the IC scans the SEG1/KS1-SEG10/KS10 waveform inside the chip after power-on as shown in figure (10):
As shown in figure (10), the internal button scanning principle of the chip is as follows: the chip gradually scans from SEG1/KS1 to SEG10/KS10, and
SEG1/KS1-SEG8/KS8 is completed in one cycle, and SEG9/KS9-SEG10/KS10 is completed in the next cycle. When sending the read button command, if
SEG1/KS1-SEG10/KS10 terminal button scan high level is introduced into K1/K2/K3 pin through button, and the chip will recognize the high level and read 5
For Button bytes of data, the corresponding BIT is set to high.
▲Note:The display period is related to the oscillation frequency of IC operation, and the oscillation frequency is not completely consistent. The above data is for reference only, and the actual measurement shall prevail.
6.2.2) button reuse:Composite button: SEG1/KS1-SEG10/KS10 is reused for display and button scan. Take figure (12) as an example,
The display needs D1 to be on and D2 to be off. You need to set SEG1 to "0" and SEG2 to "1". If S1 and S2 are pressed at the same time, it is equivalent to SEG1 and SEG2 is short-circuited. This
When D1,D2 are all lit.
Solution:
6.2.2.1. On the hardware, you can set the keys that need to be pressed at the same time on different k lines as shown in figure (13),
6.2.2.2. The series diode is shown in figure (14).
▲Note: We recommend that you use the same K key with different KS as the composite button.
VII. Communication timing and data transmission
The chip supports two data transmission modes:
7.1. Automatic address addition mode: write multiple bytes of data continuously with high efficiency;
Using the automatic address plus 1 mode, setting the address is actually the starting address of the transmitted data stream. Start address command word sent
Bi, "STB" does not need to be high to follow the data transmission, up to 14 bytes, and "STB" will be high only after the data transmission is completed.
Command1: Set the display mode
Command2: set data commands
Command3: Set the display address
Data1 ~ n: transmit display data to the Command3 address and the following address (up to 14bytes)
Command4: Display Control commands
7.2. Fixed Address mode: the address must be set separately for each byte of data, which is flexible.
Using the fixed address mode, setting the address is actually setting the address where the 1byte data to be transmitted is stored. The address has been sent, "STB"
You do not need to set the value to high. The data is transmitted immediately after 1byte. The STB value is set to high only after the data is transmitted. Then reset the address where the second data needs to be stored,
Up to 14 bytes of data has been transferred, and the STB is set to high.
Command1: Set the display mode
Command2: set data commands
Command3: set display address 1
Data1: transfer display data from 1 to Command3 addresses
Command4: set display address 2
Data2: transfer display data from 2 to Command4 addresses
Command5: Display Control commands
When reading button, you must wait at least 2 seconds after the 8th rising edge of CLK before reading data.
7.3. Read button time series
Command1: Set the read button command
Data1 ~ 5: Read button data
7.4. Program design flow chart using automatic address plus one and fixed address:
7.4.1) program design flow chart using automatic address plus one:
7.4.2) program design flow chart with fixed address:
7.5. Serial data transmission format:
Both the read and receive bits operate on the rising edge of the clock.
▲Note: 1. When reading data, you need to set the command from the 8th rising edge of the serial clock CLK to CLK failling edge.
Waiting time Twait (minimum 2μs). For more information, see Time series feature table.
VIII. Application circuit design suggestions
8.1. Co-negative/co-positive Circuit: refer to Figure (18) and figure (19) in the technical document;
8.1.1) hardware circuit diagram of CXLE88142 co-Yin digital screen (18)
8.1.2) hardware circuit diagram of CXLE88142 co-Yang digital screen (19)
▲Note:1. Filter capacitor wiring between VDD and GND should be placed as close to PCB board chips as possible to enhance the filtering effect.
2. Connecting three 100pF capacitors at the DIO, CLK, and STB communication ports up and down can reduce the interference to the communication ports.
3. Since the conduction voltage of blue light digital tube is reduced by about 3V, 5V should be selected for CXLE88142A power supply.
8.2. Filter capacitor: The capacitor between VDD and GND should be placed near the chip;
8.3. Anti-interference of communication lines: We recommend that you connect 100pF capacitors in parallel to the ground for DIO, CLK, and STB lines;
8.4. Power supply suggestions: use 5V power supply to be compatible with blue light digital tube (voltage drop is about 3V).
IX. Summary of electrical parameters
9.1. Working voltage: 3V to 6v (5V recommended)
9.2. Output current: The maximum SEG pin is 60mA, and the maximum GRID pin is 200mA.
9.3. Working temperature:-40 ℃ ~ 80 ℃
9.4. Communication frequency: up to 1MHz
9.5. Limit parameters (Ta = 25℃, Vss = 0V)
9.6. Normal operating range (Ta = -20 ~ 80℃,Vss = 0V)
9.7. Electrical characteristics (Ta = -20 ~ 80℃,VDD = 5V, VSS = 0V)
9.8. Switching characteristics (Ta = -20 ~ 80℃,VDD = 5V)
9.9 time series characteristics (Ta = -20 ~ 80℃,VDD = 5V)
9.10. Time Series Waveform diagram:,
X. Summary
CXLE88142A is a powerful and flexible LED driver and keyboard control chip, especially suitable for household appliances, industrial control and intelligent display devices. Its rich display mode, reliable keyboard scanning mechanism and simple serial communication interface make it an ideal choice for many embedded display systems. During the design, attention should be paid to the initialization of video memory, pin connection mode and anti-interference layout to ensure the stable operation of the system.
This article is based on the CXLE88142A Technical Manual. The content is for reference only. For practical application, please refer to the latest official information.
Thirteen, relevant chip selection guideMore similar products.....
|
Model |
Number of interfaces |
Drive dot matrix number |
Segment/bit |
Co-negative Drive |
Co-positive drive |
Button |
Encapsulation form |
Remarks |
|
3 |
28 |
7*4 |
7-segment 4-bit |
- |
- |
SOP16/DIP16 |
LED panel display driver chip |
|
|
3 |
21 |
8*2/7*3 |
8-segment 2-bit/7-segment 3-bit |
- |
6*1 |
SOP16 |
LED panel display driver chip |
|
|
3 |
35 |
5*7/8*4 |
7-segment 5-bit/8-segment 4-bit |
7 segments and 5 digits |
5*1 |
SOP18/DIP18 |
LED panel display driver chip |
|
|
3 |
48 |
6*7/9*4 |
7-segment 6-bit/9-segment 4-bit |
7-segment 6-bit |
6*1 |
SOP20 |
LED panel display driver chip |
|
|
3 |
48 |
8*6/10*4 |
8-segment 6-bit/10-segment 4-bit |
- |
- |
SOP20 |
LED panel display driver chip |
|
|
4 |
77 |
11*7/14*4 |
11 Segment 7 bit/14 Segment 4 bit |
7-segment 11-bit |
10*3 |
SOP32 |
LED panel display driver chip |
|
|
4 |
77 |
11*7/14*4 |
11 Segment 7 bit/14 Segment 4 bit |
7-segment 11-bit |
10*3 |
SOP32 |
LED panel display driver chip |
|
|
3 |
77 |
11*7/14*4 |
11 Segment 7 bit/14 Segment 4 bit |
7-segment 11-bit |
- |
SOP24/QSOP24 |
LED panel display driver chip |
|
|
3 |
70 |
10*7/13*4 |
10-segment 7-bit/13-segment 4-bit |
7-segment 10-bit |
10*2 |
SOP28 |
LED panel display driver chip |
|
|
3 |
70 |
10*7/13*4 |
10-segment 7-bit/13-segment 4-bit |
7-segment 10-bit |
10*2 |
SOP28 |
LED panel display driver chip |
|
|
3 |
70 |
10*7/13*4 |
10-segment 7-bit/13-segment 4-bit |
7-segment 10-bit |
10*2 |
SOP28 |
LED panel display driver chip |
|
|
3 |
128 |
16*8 |
16-segment 8-bit |
8-segment 16-bit |
- |
SOP32 |
LED panel display driver chip |
|
|
3 |
112 |
14*8 |
14-segment 8-bit |
8-segment 14-bit |
8*2 |
SOP32 |
LED panel display driver chip |
|
|
3 |
120 |
15*8 |
15-segment 8-bit |
8-segment 15-bit |
8*1 |
SOP32 |
LED panel display driver chip |
|
|
3 |
96 |
12*8 |
12-segment 8-bit |
8-segment 12-bit |
8*4 |
SOP32 |
LED panel display driver chip |
|
|
4 |
128 |
16*8 |
16-segment 8-bit |
8-segment 16-bit |
8*4 |
QFP44 |
LED panel display driver chip |
|
|
3 |
80 |
10*8 |
10-segment 8-bit |
8-segment 10-bit |
8*3 |
SOP28 |
LED panel display driver chip |
|
|
3 |
64 |
8*8 |
8-segment 8-bit |
8 segments and 6 digits |
4*2 |
SOP24/QSOP24 |
LED panel display driver chip |
|
|
2 |
128 |
8*16 |
8-segment 16-bit |
16-segment 8-bit |
- |
SOP28, SSOP28 |
LED panel display driver chip |
|
|
3 |
70 |
10*7/13*4 |
10-segment 7-bit/13-segment 4-bit |
7-segment 10-bit |
10*2 |
SOP24/SSOP24/SDIP24 |
LED panel display driver chip |
|
|
4 |
77 |
11*7/14*4 |
11 Segment 7 bit/14 Segment 4 bit |
7-segment 11-bit |
10*3 |
SOP32 |
LED panel display driver chip |
|
|
2 |
128 |
8*16 |
8-segment 16-bit |
16-segment 8-bit |
- |
SOP24 |
LED panel display driver chip |
|
|
2 |
144 |
8*9*2 |
Positive and negative push digital tube |
Positive and negative push digital tube |
- |
QSOP24 |
LED panel display driver chip |
|
|
3 |
70 |
10*7/13*4 |
10-segment 7-bit/13-segment 4-bit |
7-segment 10-bit |
Touch Button 8 |
SOP32 |
LED panel display driver chip |
|
|
5 |
120 |
15*8 |
15-segment 8-bit |
8-segment 15-bit |
8*1/8 |
QFN48 |
LED panel display driver chip |
|
|
3 |
77 |
11*7/14*4 |
11 Segment 7 bit/14 Segment 4 bit |
7-segment 11-bit |
10*1 |
SOP24 |
LED panel display driver chip |
|
|
3 |
128 |
8*16 |
8-segment 16-bit |
16-segment 8-bit |
- |
SOP32 |
LED panel display driver chip |
|
|
3 |
28 |
7*4 |
7-segment 4-bit |
- |
- |
SOP16/DIP16 |
LED panel display driver chip |
|
|
3 |
21 |
8*2/7*3 |
8-segment 2-bit/7-segment 3-bit |
- |
6*1 |
SOP16 |
LED panel display driver chip |
|
|
3 |
35 |
5*7/8*4 |
7-segment 5-bit/8-segment 4-bit |
7 segments and 5 digits |
5*1 |
SOP18/DIP18 |
LED panel display driver chip |
|
|
3 |
48 |
8*6/10*4 |
8-segment 6-bit/10-segment 4-bit |
- |
- |
SOP20 |
LED panel display driver chip |
|
|
3 |
48 |
6*7/9*4 |
7-segment 6-bit/9-segment 4-bit |
7-segment 6-bit |
6*1 |
SOP20 |
LED panel display driver chip |
|
|
4 |
77 |
11*7/14*4 |
11 Segment 7 bit/14 Segment 4 bit |
7-segment 11-bit |
10*3 |
SOP32 |
LED panel display driver chip |
|
|
3 |
77 |
11*7/14*4 |
11 Segment 7 bit/14 Segment 4 bit |
7-segment 11-bit |
- |
SOP24/QSOP24 |
LED panel display driver chip |
|
|
4 |
77 |
10*7/13*4 |
10-segment 7-bit/13-segment 4-bit |
7-segment 10-bit |
10*1 |
SOP32 |
LED panel display driver chip |
|
|
3 |
77 |
11*7/14*4 |
11 Segment 7 bit/14 Segment 4 bit |
7-segment 11-bit |
10*3 |
QFP44 |
LED panel display driver chip |
|
|
3 |
70 |
10*7/13*4 |
10-segment 7-bit/13-segment 4-bit |
7-segment 10-bit |
10*2 |
SOP28 |
LED panel display driver chip |
|
|
3 |
70 |
10*7/13*4 |
10-segment 7-bit/13-segment 4-bit |
7-segment 10-bit |
10*2 |
SOP28 |
LED panel display driver chip |
|
|
4 |
128 |
16*8 |
16-segment 8-bit |
8-segment 16-bit |
8*4 |
QFP44 |
LED panel display driver chip |
|
|
3 |
128 |
16*8 |
16-segment 8-bit |
8-segment 16-bit |
- |
SOP32 |
LED panel display driver chip |
|
|
3 |
112 |
14*8 |
14-segment 8-bit |
8-segment 14-bit |
8*2 |
SOP32 |
LED panel display driver chip |
|
|
3 |
120 |
15*8 |
15-segment 8-bit |
8-segment 15-bit |
8*1 |
SOP32 |
LED panel display driver chip |
|
|
3 |
96 |
12*8 |
12-segment 8-bit |
8-segment 12-bit |
8*4 |
SOP32 |
LED panel display driver chip |
|
|
3 |
35 |
7*5/8*4 |
7-segment 5-bit/8-segment 4-bit |
- |
7*1 |
DIP18 |
LED panel display driver chip |
|
|
2 |
32 |
8*4 |
- |
8-segment 4-bit |
8*2 |
DIP18 |
LED panel display driver chip |
|
|
2 |
48 |
8*6 |
- |
8 segments and 6 digits |
8*2 |
SOP20/DIP20 |
LED panel display driver chip |
|
|
3 |
80 |
10*8 |
10-segment 8-bit |
8-segment 10-bit |
8*3 |
SOP28 |
LED panel display driver chip |
|
|
3 |
64 |
8*8 |
8-segment 8-bit |
8 segments and 6 digits |
4*2 |
SOP24/QSOP24 |
LED panel display driver chip |
|
|
2 |
128 |
8*16 |
8-segment 16-bit |
16-segment 8-bit |
- |
SOP28/SSOP28 |
LED panel display driver chip |
|
|
3 |
70 |
10*7/13*4 |
10-segment 7-bit/13-segment 4-bit |
7-segment 10-bit |
10*2 |
SOP28 |
LED panel display driver chip |
|
|
2 |
32 |
8*4 |
8-segment 4-bit/7-segment 4-bit |
- |
7*4 |
SOP16/DIP16 |
LED panel display driver chip |
|
|
2 |
28 |
7*4 |
- |
7-segment 4-bit |
7*1 |
SOP16/DIP16 |
LED panel display driver chip |
|
|
1 |
40 |
7*6/8*5 |
7-segment 6-bit/8-Segment 5-bit |
6-segment 7-bit/5-segment 8-bit |
- |
SOP16 |
LED panel display driver chip |
|
|
3 |
70 |
10*7/13*4 |
10-segment 7-bit/13-segment 4-bit |
7-segment 10-bit |
10*2 |
SOP28 |
LED panel display driver chip |
|
|
3 |
70 |
10*7/13*4 |
10-segment 7-bit/13-segment 4-bit |
7-segment 10-bit |
10*2 |
SOP24/SSOP24/SDIP24 |
LED panel display driver chip |
|
|
2 |
256 |
32*8/24*16 |
32-segment 8-bit/24-segment 16-bit |
8-segment 32-bit/16-segment 24-bit |
- |
LQFP48/LQFP52 |
LED panel display driver chip |
|
|
4 |
256 |
32*8/24*16 |
32-segment 8-bit/24-segment 16-bit |
8-segment 32-bit/16-segment 24-bit |
- |
LQFP48/LQFP52 |
LED panel display drive core |
