Hi,
I was just wondering how the OFFSETCAL command on the ADS131E06 converter works. The datasheet specifies:
"This command is used to cancel the channel offset. OFFSETCAL must be executed every time there is a change in PGA gain settings."
But it says nothing about how it works or how long it takes.
In my application I first initialize all the channels and then perform OFFSETCAL. Short after initializing the converter is started by pulling the start pin high. I need to do some switching in my electronics between two conversions, so I am pulling the start pin low after a few microseconds. This allows me to stop the ADC after a single conversion. When the conversion is done, DRDY goes low and an interrupt is started. The interrupt routine performs the switching and restarts the ADC by pulling the start pin high again.
This works fine, however when I use OFFSETCAL in my init function, I noticed that DRDY never goes low and no interrupt is started. After some debugging I found that I should held the start pin high for about 150 miliseconds before DRDY went low for the first time. It looks like the converter is performing the offset callibration after it is started and not directly when the OFFSETCAL command is send. However, this is not documented in the datasheet.
Could someone please explain how the Offset Calibration is performed and what the timing requirements are?
Many thanks.
