Hello all,
I am pulling my hair out. I cannot get any communication from either of the 2 AD7731 ADCs I have. I am creating a new hardware rev of a water sanitation system. The OLD hardware was AD7731 and Atmel128. New hardware is AD7731 and PIC18f45k22.
I have ported the code from the atmel to the PIC. I am confident in the Code as I can talk to other SPI devices on the board just fine. As for the AD7731 I cannot get any response from the IC at all. No !RDY pin low, no ability to read the registers, etc. !RDY stays high at all times. I received the parts as Analog.com samples. The !RDY pin NEVER goes LOW. No matter how long I wait.
Here are snippets of my setup and communication code.
// Initialize SPI
// MCU is running @32Mhz, divide FOSC/64 to run SPI @ 500Khz.
//(Have tried, 2Mhz, 4Mhz, and 8Mhz)
SPI1_Init_Advanced(_SPI_MASTER_OSC_DIV64, _SPI_DATA_SAMPLE_MIDDLE, _SPI_CLK_IDLE_LOW, _SPI_LOW_2_HIGH);
void Setup_AD7731(void){
write_register(0x03, 0x13, 0x34); //Initialize filter register.
// Self calibrate millivolt input (Electrode Inputs)
/*----------------------------------------------------------------------------*/
// Calibrate Zero point
write_register(0x02, 0x90, 0xF6); //Self calibrate mV input zero.
while(AD7731_DR != LOW); //Wait for the ready pin to go low.
// Set to Full Scale
write_register(0x02, 0xB0, 0xF6); //Self calibrate mV input full scale.
while(AD7731_DR != LOW); //Wait for the ready pin to go low.
}
}
void write_register(char reg, char msb, char lsb)
{
SELECT_AD7731; //Select the a/d converter.
SPI1_Write(reg); //Select the required a/d register.
SPI1_Write(msb); //Send msb byte.
SPI1_Write(lsb); //Send lsb byte.
DISABLE_AD7731; //De-select a/d converter.
}
This is a direct port from a working system. I am loosing my mind here. Anyone see what I am doing wrong?
I am pulling my hair out. I cannot get any communication from either of the 2 AD7731 ADCs I have. I am creating a new hardware rev of a water sanitation system. The OLD hardware was AD7731 and Atmel128. New hardware is AD7731 and PIC18f45k22.
I have ported the code from the atmel to the PIC. I am confident in the Code as I can talk to other SPI devices on the board just fine. As for the AD7731 I cannot get any response from the IC at all. No !RDY pin low, no ability to read the registers, etc. !RDY stays high at all times. I received the parts as Analog.com samples. The !RDY pin NEVER goes LOW. No matter how long I wait.
Here are snippets of my setup and communication code.
// Initialize SPI
// MCU is running @32Mhz, divide FOSC/64 to run SPI @ 500Khz.
//(Have tried, 2Mhz, 4Mhz, and 8Mhz)
SPI1_Init_Advanced(_SPI_MASTER_OSC_DIV64, _SPI_DATA_SAMPLE_MIDDLE, _SPI_CLK_IDLE_LOW, _SPI_LOW_2_HIGH);
void Setup_AD7731(void){
write_register(0x03, 0x13, 0x34); //Initialize filter register.
// Self calibrate millivolt input (Electrode Inputs)
/*----------------------------------------------------------------------------*/
// Calibrate Zero point
write_register(0x02, 0x90, 0xF6); //Self calibrate mV input zero.
while(AD7731_DR != LOW); //Wait for the ready pin to go low.
// Set to Full Scale
write_register(0x02, 0xB0, 0xF6); //Self calibrate mV input full scale.
while(AD7731_DR != LOW); //Wait for the ready pin to go low.
}
}
void write_register(char reg, char msb, char lsb)
{
SELECT_AD7731; //Select the a/d converter.
SPI1_Write(reg); //Select the required a/d register.
SPI1_Write(msb); //Send msb byte.
SPI1_Write(lsb); //Send lsb byte.
DISABLE_AD7731; //De-select a/d converter.
}
This is a direct port from a working system. I am loosing my mind here. Anyone see what I am doing wrong?
