Hello Team, I would like to verify the adc codes for some known input voltages for the testing purpose. As I found from datasheet, maximum differential input would be 2.5v for my case. I supplied 3.3v of the evm board to the AINP1 and 1.8v(of evm) to the AINN1; differential 1.5. I am using jumpers from J8 to J6 of EVM board for the same.
+VA and -VA of MMB0 is connected to +15v and -15v (max input as specified in the user guide) and GND to GND of supply.MMB0 is configured as figure 7 of section 9.3.1.
ADS1282EVM configuration is left unchanged i.e. switch S1 chooses onboard reference 5v (unipolar mode), Jumper J3 chooses onboard 4.096MHZ as clock source, all heads of jumper J7 shorted and rest as shown in figure 4 of section 8.3.
SPI MODE = 0
SPI SCLK = 1.024 MHZ
Data Rate: 1000SPS
Digital Filter: SINC+LPF(FIR)
PGA GAIN: 1
I am reading adc codes after DRDY goes low in read data by command mode.The adc codes for the same configuration moves around the value 210,000,000 to 220,000,000 which gives volatge as 0.25v as calculated from formula:
(ADC_CODE) * (2.5) / (2^31)
Where am I going wrong?Can't I use those DC volatges for verification purpose?
