CS5460 SW/HW problem

[Hexer379]

Hello to all Users ...

I have a problem with this IC and configuration.

HW: STM32 and CS5460A as an measuring device.
(https://www.farnell.com/datasheets/32393.pdf) from site 28 and 31 (3.8.7.2 DC Offset Calibration Sequence)

I can retrieve data from the ADs, the values correspond to the expected values.
As a result to a single AD shot , i get the Data_Ready bit without problems.
The different modes also work ... so the SPI is working without any problems.

But I can't get any further with the calibration of the IC. -> cs5460_calibrateACVoltageOffset()
If I shorted the 2 ADs for the offset-cal. then the loop does not come to the end , the Data_Ready bit does not switch to 1 ... the status-bytes are "0" .
Does anyone have a tip or a solution for this?

Code:

cs5460.h:

// commands for calibrate control
#define CALIBRATE_CONTROL    0xC0
#define CALIBRATE_CURRENT    0x08
#define CALIBRATE_VOLTAGE    0x10
#define CALIBRATE_CURRENT_VOLTAGE  0x18    // both chan.
#define CALIBRATE_GAIN      0x02
#define CALIBRATE_OFFSET    0x01
#define POWER_UP_HALT_CONTROL    0xA0
#define DATA_READY      (0x01L<<23)

cs5460.c:

unsigned int cs5460_getStatus()
{
  return cs5460_readReg(STATUS_REGISTER);
}
void cs5460_clearStatus(uint32_t cmd)
{
  cs5460_writeReg(STATUS_REGISTER, cmd);
}
void cs5460_calibrate(uint8_t cmd)
{
  cmd = (CALIBRATE_CONTROL | cmd);
  printf("start cal with mask %i ... \n",cmd);
  printf("start with status ... %i \n",cs5460_getStatus());
  cs5460_send(POWER_UP_HALT_CONTROL);
  cs5460_clearStatus(DATA_READY);
  printf("now in status ... %i \n",cs5460_getStatus());
  cs5460_send(cmd);
  delay_ms(1250);                
  while(!(cs5460_getStatus() & DATA_READY)) {    printf("wait toooooooo long ... %i \n",cs5460_getStatus());
  delay_ms(1000);
  };
  // wait until data ready;
  cs5460_clearStatus(DATA_READY);
}

uint32_t cs5460_calibrateACVoltageOffset()
{
  cs5460_calibrate(CALIBRATE_VOLTAGE | CALIBRATE_OFFSET);
  return cs5460_readReg(VOLTAGE_AC_OFFSET_REGISTER);
}

uint32_t cs5460_calibrateDCVoltageOffset()
{
  cs5460_calibrate(CALIBRATE_VOLTAGE | CALIBRATE_OFFSET);
  return cs5460_readReg(VOLTAGE_DC_OFFSET_REGISTER);
}

[sam_des]

Hi,

For both DC/AC offset calibration, you need to not just short, but ground both pins of ADC.
And you need to set Voltage/Current Gain registers to 1 & offset registers to 0, along-with stopping any on-going ADC conversions before starting calibration.
Check your Cycle Count register, AC calibration takes 6N+30 AD conversion cycles to complete, where N is value of cycle count.

Also there is App-note AN227, specifically for calibrating CS5460.

Hope that helps.

sam_des

[Hexer379]

Hi ,

THANK you very much !!!!
That was the problem ... set the registers and it works now !

Thomas ...