DRV8301: DRV 8301 SPI write not working

Hi Saraj,

Please try reading register 0x01 twice and report the result both times. The second read should be correct.

Please note the SPI read operation described in 7.5.1.1 of the datasheet.

If you do not read the correct value, please provide scope captures of the first and second read.

#include <SPI.h>
#define ss digitalWrite(10, LOW);    
#define nss digitalWrite(10, HIGH);    
const int chipSelectPin = 10;
const int EN_GATE = 8;
void setup() {
  Serial.begin(9600);
  pinMode(chipSelectPin, OUTPUT);
  pinMode(EN_GATE, OUTPUT);
  digitalWrite(EN_GATE, HIGH);
  digitalWrite(chipSelectPin, LOW);   
  SPI.begin();
  // DRV8301 communicates with MSB first and has low clock polarity and data is shifted on rising edge
//  SPI.beginTransaction(SPISettings(4000000, MSBFIRST, SPI_MODE1));
  SPI.setBitOrder(MSBFIRST);
  SPI.setDataMode(SPI_MODE1); //  While Idle SPI CLK = 0, falling Egde latching for Rx
}

void loop() {
  readRegister(0x02);
  delay(5000); 
}

unsigned int readRegister(byte Register ) {
  uint16_t dataToSend = 0x0000,dataToRead = 0;
  //   bit   1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16
  //   R=1/W=0  |-Raddr--|  |-----------Data---------------------|
  // Fault=1/0  |-Raddr--|  |-----------Data---------------------|
  dataToSend |= ( 0x0010 | Register) ;
  dataToSend <<= 11;
  Serial.print("Sending read command: ");
  Serial.println(dataToSend,HEX);
  ss
  Serial.println(SPI.transfer16(dataToSend),HEX);
  Serial.println(SPI.transfer16(dataToSend),HEX);
  nss
}

void writeRegister(byte Register, byte Value) {
  uint16_t dataToSend = 0;
  //   bit   1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16
  //   R=1/W=0  |-Raddr--|  |-----------Data---------------------|
  dataToSend |= Register ;
  dataToSend <<= 11;
  dataToSend |= Value;
  Serial.print("Sending write command: ");
  Serial.println(dataToSend,HEX);
  ss
  Serial.println(SPI.transfer16(dataToSend),HEX);  //Send value to record into register
  nss
  // take the chip select high to de-select:
  Serial.print("Reading reply for write command: ");
  Serial.println(dataToSend,HEX);
}

Hi Rick,

       Above is arduino code I'm using to print SPI data received twice. Attached is figure from DSO I observed that there is no signal on MISO pin even after trying for more than half and hour. I measured supply current to DRV8301 it takes about 50mA at 24V when only SPI is powered on. And DRV heats up to 130 C temperature in just 15 minutes. I have not connected any MOSFET circuitry to DRV but rest of the circuitry is same as shown in reference design and it still is heating up a lot.

In figure, topmost signal is clock, then second is MOSI(from microcontroller) then third is MISO and fourth is slaveSelect.

What am I missing?

Hi Saraj,

Please refer to post: e2e.ti.com/.../1723924

This is similar to what you are describing. It is important to ensure nSCS is "framing" the SPI command as described on page 21 of section 7.5.1.1 of the datasheet.

Also please zoom out to capture both SPI read transactions. One of the reads should have bit D10 set as a 1.