Hello,
I follow the instructions on page 63 of the manual to set up DC lead-off detection, copied here for your convenience:
10.1.2.1 Lead-Off
Sample code to set dc lead-off with pull-up and pull-down resistors on all channels.
WREG LOFF 0x13 // Comparator threshold at 95% and 5%, pullup or pulldown resistor dc lead-off
WREG CONFIG4 0x02 // Turn on dc lead-off comparators
WREG LOFF_SENSP 0xFF // Turn on the P-side of all channels for lead-off sensing
WREG LOFF_SENSN 0xFF // Turn on the N-side of all channels for lead-off sensing
Observe the status bits of the output data stream to monitor lead-off status.
I am looking at the status bits in DOUT, specifically the contents of the LOFF_SENSP and LOFF_SENSN registers, but the results don't make sense. For instance, I see that all the P-side leads are disconnected but none of the N-side leads are disconnected. When I connect only one of the P-leads (for channel 5 or 6 for example), I see that 4 different channels are reported to be connected (1-4, for example). This continues for a while (maybe around a minute) and even after I disconnect the one lead again, before the channels are marked as disconnected again, one by one. Is any part of this behavior expected? What could this inaccuracy be due to?
For reference, I am using both P and N sides of channels of the first four channels, and only the N side for the last four channels (and activating both bias and SRB2).