I purchased the TLC5947 24 channel PWM LED Driver module in hopes of running all my B-737 autopilot Switch LED's.  The board I received has only the following pins GND, OE, SCL, SDA, VCC and V+ .  All the wiring diagrams show using the D L and S(sig) pins but I don't have an S pin on this board, Did I get the wrong board?  If not how to I wire it and assign in the configurator?  Thanks in advance, just need to know whether I need to quit trying to get this board to work.  I guess also if this board doesn't work what should board should I get to drive the LED's

ago in Wiring, Powering by

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You cannot use this board, as it has I2C interface.

Probably you have PCA9685, not TLC5947?

Anyway, it's better (for speed reason) to use the LED drivers  (DM13A) or registers for all your LEDs. You don't need PWM to control them in MCP. Also, you can use the MAX7219 for 64 LED.


ago by

Thanks once again!  got some bad info but still progressing.yes

Update:  "Max 7219 LED's not lighting":

"I have connected the 7219 to the Mega 2560 as follows:

7219       - Pin #1 (DIN) to Pin #28 on Mega 2560

                - Pin #2 (DIG0) to LED Negative leg

                - Pins #4 & 9 to GND on Mega

                - Pin #12(Load(CS)) to pin #27 on the Mega

                - Pin #13(CLK) to pin 37 on the Mega  (Also have 2K resistor connected to ground on this pin)

                - Pin #19(V+) to 5V+ on Mega

                - Pin #18(ISET) to 5V+ on Mega through the 22K resistor I use for my 7 segment displays

I have tried configuring Pin #37 on the Mega as LED Driver, Matrix and LED Driver, Serial.  I have also tried different pins on the Mega.  The LED's work when directly connected to the MEGA but I get no LED action through the MAX 7219.  I assigned the LED Driver Matrix, pin 0 to AT_ARM_ON and have verified LED operation when directly connected to Mega, just nothing when connected through the 7219.

Please advise if you can see what I am doing wrong.  (also Have checked voltage to 7219, and I have 5V+ to both sides of LED (Pin 2  (DIN 0) has +5V when measured with my meter) + side of LED connected to 5V+ on Mega and GND side connected to 7219 Pin #2(DIG 0)




To be sure, if you got your 7-segmet display working on the single MAX7219 chip, simply use it for checking the LEDs, there is no difference.

I.e., assign the LEDs as "LED driver matrix" , connect your 7-segment working display and  you can see the corresponding segments lit.

If all works, you can continue with another MAX.

As you can see on the page, I recommend to use assembled MAX7219 dot matrix module