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Topic: digiPot and IMU not compatible on SPI bus (Read 38 times) previous topic - next topic

pc_john


Arduino Uno
IMU - http://www.jebobrow.com/
digiPot - https://www.arduino.cc/en/Tutorial/SPIDigitalPot

IMU data goes erratic just as soon as digiPot SPI.transfer(address) command is used.

void digitalPotWrite(int address, int value) {
  digitalWrite(slaveSelectPin,LOW);    // select the chip:



--> here //  SPI.transfer(address);  // send address and value via SPI:



//  SPI.transfer(value);
  digitalWrite(slaveSelectPin,HIGH);   // de-select the chip:
}

If I leave the comments in on that line, the IMU gives good data.  If I uncomment that line, the data from the IMU is incorrect.  Do I need to use beginTransaction () or some such?  Why doesn't this work?

SPI bus?
http://www.dorkbotpdx.org/blog/paul/better_spi_bus_design_in_3_steps

pc_john

circuit is clk common to both, spi (in) common to both and digiPot chip select to arduino 7 and IMU CS to Arduiono 8

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