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Topic: TPIC6B595 Troubles (Read 11394 times) previous topic - next topic


Not sure if you have picked this up but pins 10 & 11 on the chip should also be connected to ground, this is not shown on you diagram.

For the definitive guide to decoupling


I've received the caps but I'm not quite sure where to place them in my current layout.  I'm thinking that I may need to change the power/ground layouts on the board for them to work correctly?

Is anything else incorrect?



Just put the cap between the power and one of the grounds as close to the chip as you can get.


I currently have this:

I am using this code:
Code: [Select]

#include <SPI.h>

void setup() {
  pinMode(SS, OUTPUT);
  SPI.begin();// library takes care of D11,12,13

void loop(){
  // say 3 devices being used
  digitalWrite (SS,LOW);  // SS (D10)goes to SRCK PIN on all devices
  SPI.transfer(0);  // SCK (D13) goes to clock pin on all devices
  //SPI.transfer(255);  // MOSI (D11) goes to serial data pin on device 1,
  //SPI.transfer(byte3);  // SEROUT from device 1 goes to device 2, etc
  digitalWrite (SS,HIGH);  // outputs update on this rising edge
  // check if byte1,2,3,4 need update
  // etc.

No matter what value I put in the SPI.transfer() it still only lights up the last LED and it is also lighting up the LED on pin13 on the Arduino Uno itself.

It's late and I'm sure I'm just missing something simple, hoping anyway.



Is this the exact type of breadboard you have?

It seems you didn't bridge the power rails in the middle (near #30 or so).


Sorry for the confusion there.  I've only spread things out on the diagram to make it easier to see.  I have everything contained on my actual breadboard between 0 and 30.  I'm still learning to use Fritzing so making things further apart makes it easier to make sure everything is hooked up the way it should be.

Thanks for the idea though.


I knew that this project should be that hard...

I ordered 3 TPIC6B595 shift registers from a local electronics house.  It turns out that I was shipped 3 74HCT299N shift registers which are of course completely different.  So I have to deal with them to get the right product now before I can continue on this project.

I know I should have looked but I trusted that they would be able to ship the product that was ordered when there are such small differences in parts...lesson learned.

Thank you all very much for your time, hopefully once I have the right part I will be able to just plug it in and everything will be working as desired thanks to your help.


I had similar problem and found solution. The important information is that TPIC6B595 (unlike 74HC595) can only sink (!) current (found this here). So it is necessary to connect TPIC6B595 "outputs" (in datasheet they are called DRAINs, obviously, not without purpose) to the cathodes of LEDs. It is also important for choosing right LED matrix: with common anode or common cathode.

P.S.: I know that this thread is old, but hope that somebody will find this post useful.


See also other variations for different current sinking capability & package sizes:
TPIC6595, 6A595, 6B595, 6C595, 6D595
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

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