We are currently using ADS1282-HT and running into some problems. After lots of research thru the forum, we are able to get the chip to read the data by command. Currently we are stuck in the OFFSETCAL & GANCAL. Note that we are trying to follow Figure 66 of the spec. Plus, input MUX was set to 100 where AIN2 was connected to GND to generate the zero input for OFFSETCAL.. Here is our sequence -
1) SDATAC
2) SYNC
3) 32ms delay
4) RDATAC
5) Wait for DRDY to go low
6) ~90us (DRDY goes low)
7) SDATAC
8) OFFSETCAL or GANCAL
9) RDATAC
Here are a list of questions,
1) DRDY does not mimic what's in Figure 66. In our system, DRDY goes low follows RDATAC command and then stays high. Note that it only take 90us between RDATA and DRDY goes low... Is this okay?
2) GANCAL, what is the input signal? Does it has to be positive/negative full scale? Or any input in between?
3) Are there SPI and DRDY waveforms on how GANCAL/OFFSETCAL is supposed to behave?
Thanks,
Ji Ye Lin