Myujth

I am trying to decode the signals going to shift registers in my washing machine. The registers are STP16CPC05 which also happen to be LED drivers. I am trying to get status from my washing machine like time left, which cycle, check if its done, etc. with an ESP12. If I can read the signals going to the LED drivers, I can determine which bits are for which LED and then determine status in my program.

My first thought was to use a custom shiftin but I had no luck with that (and supposedly digitalread() is too slow anyway) and I was reading everywhere that I should "just use SPI" since it's faster. I have been able to successfully read the signals using a logic analyzer and even made a script for an arduino pro mini that emulates the register signals so that I can more easily debug my ESP12 without running the washer all day. Writing an SPI master is relatively easy but the slave is the hard part. Here is the code for the Arduino Pro mini so it can emulate the washer signals:

// SPI master code for Arduino Pro Mini "washing machine clone"

#include <SPI.h>


void setup (void)


 SPI.begin ();

 SPI.setClockDivider(SPI_CLOCK_DIV8);




void loop (void)

 delayMicroseconds(200);
 SPI.transfer(0x00); //00 00 11 01 08 01 08 02 02 00 00 0C 67 66 80
 SPI.transfer(0x00);
 SPI.transfer(0x11);
 SPI.transfer(0x01);
 SPI.transfer(0x08);
 delayMicroseconds(180);
 SPI.transfer(0x01);
 SPI.transfer(0x08);
 SPI.transfer(0x02);
 SPI.transfer(0x02);
 SPI.transfer(0x00);
 delayMicroseconds(180);
 SPI.transfer(0x00);
 SPI.transfer(0x0C);
 SPI.transfer(0x67);
 SPI.transfer(0x66);
 SPI.transfer(0x80);
 delayMicroseconds(200); 

Does anyone have any idea on how to make a simple SPI slave on esp? Or is there a better way to sniff this shift register bus? The clock signal is 1 MHZ so it isn't terribly fast. I only need to read 15 bytes at a time.

This was promising but it's been alot of work stripping it down to what I want: https://github.com/JiriBilek/WiFiSpi. I can get it to print out the data once but then I think it is having issues resetting the receive interrupt because it is expecting an interactive master.

There is a SPISlave library in the esp8266 Arduino package. With examples. (Jiri Bilek's firmware has only a modified copy of it.)