ADS1248: When I read data form dout pin of ADS1248,sometime readback data is 0?

Hi,


Reading data from the ADS1248, you may get unusual results if you do not time the data read correctly.

If you look at Figure 73 on page 42 of the datasheet, you'll see that after /DRDY goes low (indicating a new conversion has completed), the data is clocked out using SCLK and read out from DOUT/DRDY. If you do not wait for the next /DRDY (as the ADC has not completed a new conversion), clocking extra SCLKs into the device does not get you any more data and may result in reading all 0s.

One thing you can do to avoid this problem is to issue an SDATAC command. This stops the data from automatically being put onto the output register at the completion of a new conversion. To read data, you must send an RDATA command, and then clock out 24 more SCLKs to retrieve the data.

If you are able, try making this modification. If you have any other data readout issues, feel free to post back.


Joseph Wu