Communication established

A project log for PIXI Analog Shield

An Arduino Shield using the Maxim MAX11300 for 20 Programmable Mixed-Signal I/O with 12-Bit ADC, 12-Bit DAC, Analog Switches, and GPIO

magicwolfiMagicWolfi 02/22/2015 at 00:340 Comments

Hooking the shield up to an Arduino and establishing communication went totally smooth until I tried to read the DEVID register. My code

const int slaveSelectPin = 10;

// Config SPI interface
pinMode (slaveSelectPin, OUTPUT);
SPI.setBitOrder(MSBFIRST) ; 

    word result = 0;
    byte read1 = 0;
    byte read2 = 0;
  //  send the address and return value via SPI:
  SPI.transfer( (address << 0x01) | PIXI_READ );
  read1 = SPI.transfer(0x00);
  read2 = SPI.transfer(0x00);


  result = (read1 << 8) + read2; 
returned 0x0424 instead of 0x0024 as specified in the datasheet.The only reason I can think of is, that my engineering samples have a different ID to make them distinguishable from production parts.

Everything else seems to work as documented and after setting up 1 DAC and 1 ADC I was able to output and read back analog voltages in 4096 steps in voltage ranges from 0V to +2.5V and 0V to 10V.

Overall a promissing start.