Go Down

Topic: Troubleshooting Multiple SMD TLC5940s (Read 398 times) previous topic - next topic

TrueBlue

Hello,

I made a pcb with 12 SMD TLC5940s daisy chained. So far I've got the first 7 working perfectly. However the LEDS connected to the remaining 5 chips don't light up at all. I've resoldered the pins on the 8th chip several times but can't seem to identify what the issue is. Is there some way I might be able to identify what pin or part is causing the issue? Perhaps with a multimeter? Everything appears to be connected.

rtek1000

Hello,

Did you test the polarity of the LEDs?

I bought some inverted!
Please avoid private messages, your question may be someone's answer in the future!

MarkT

If the 7th isn't outputting the right signal, the 8th won't work whether or not it has issues.  Check the
soldering of the output pin of the 7th LED chip?
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

Paul__B

Of course we would need to check you code (posted according to the instructions) to make sure you have not made an obvious blunder.

TrueBlue

Hello,

Did you test the polarity of the LEDs?

I bought some inverted!
The LEDs are good!

The chips and leds are being powered by an external power supply. If I only plug in the power supply without the arduino connected, the LEDS from the 8th chip actually light up.

If the 7th isn't outputting the right signal, the 8th won't work whether or not it has issues.  Check the
soldering of the output pin of the 7th LED chip?
Just checked all the connections with a multimeter. The "OUT" of the 7th chip appears to be connected to the "IN" of the 8th.

Of course we would need to check you code (posted according to the instructions) to make sure you have not made an obvious blunder.
This is what I've been using to test. But I've also tried other sketches from the TLC arduino library. Also I do have the correct number of TLCs updated in the "tlc_config.h" file.

Code: [Select]

#include "Tlc5940.h"

void setup() {
  Tlc.init();

  Serial.begin(9600);
 
}
void loop() {
 
  Tlc.setAll(4095);
     
  Tlc.update();

}



TomGeorge

Hi,

Can you post a link to where you got the library from, thanks?

Tom... :)
Everything runs on smoke, let the smoke out, it stops running....

TrueBlue


This is the library im using, though I'm fairly certain I'm experiencing a hardware issue.

https://github.com/PaulStoffregen/Tlc5940

Go Up