We’re having an issue with the ADS1018 ADC with internal reference and temp sensor in a design. We are polling the sensor every ~ 202 us, and on alternate cycles, switching between ADC mode and temp sensor mode by flipping the TS_MODE bit in the config register. The problem is, we don’t consistently get ADC and Temp data on the expected cycles. We are expecting that after the TS_MODE bit is set to 0 (ADC mode), then the data appearing on DOUT on the next cycle will be ADC data. Similarly, after TS_MODE is set to 1 (Temp mode), we expect Temp data on DOUT during the next cycle.
Can you please confirm this is how the ADS1018 should operate?
We have the device configured in continuous conversion mode.
I’ve checked the timing against the data sheet parameters, and there appears to be sufficient margin, although we are running SCLK fairly close to the Tsclk spec of 250 ns (we are running it at ~260 ns). Attached is a scope shot, with MISO/DOUT purple trace and MOSI/DIN green trace.
The complete config words we are using are:
temp: 0100010010011011
ADC: 0100010010001011
We are powering the ADS1018 at 3.3V.
The temperature and ADC data we are receiving, appears to be the correct values, just not in the expected sequence.
I will continue to troubleshoot our controller code, but please let me know if you have any insights.