HI
I am working on ADS 1256 TI 24 bit ADC. I have made the hardware connections as per the data sheet.
Specification of different pins is as follows
AVDD=5V , DVDD= 3.3V, VREFP=2.5V VREFN=GND, PDWN and RESET=3.3V and AGND, DGND and AINCOM are connected to ground and Crystal i have used is of 8MHZ for ADC.
Clock Frequency used for SPI is 2MHZ which is 1/4 of fCLKIN as per the data sheet.
I am successful to get pulses on DRDY pin hence i am assuming that my adc ic is in working condition.
But when i am trying to read anything from status register for manufacturer id but i am getting only 0xff value from the adc.
I have also tried to read the voltage through the analog channel 1 with default setting of adc but no success.
My code for reading Status register is as follows.
CE_Low();
while(DRDY);
WriteSpi(0x0F);
ADC_delay(500);
WriteSpi(0x10);
WriteSpi(0x01);
ADC_delay(130);
ch1=WriteSpi(0x00);
ch2=WriteSpi(0x00);
ch3=WriteSpi(0x00);
CE_High();
My questions are as follows
1. What is the expected id should it return when i read the status register.
2. If i execute this part of code directly without any other command of ADC will it works.
3. Which modes of SPI this ADC supports?
4. If i give the more delay than specified by data sheet will it affect the functionality of ADC?
Am I missing something?
Please Suggest some suitable help regarding the above issues.
Thank you in advance.