We have a powerup integrity test for the A2D. This includes a RESET command sent over SPI. There has been a suggestion to add a START/SYNC to the test. We use the START/SYNC after this initial test to create a conversion. The DRDY will trigger an interrupt, and we issue START/SYNC to create another conversion. We also determine if the conversion takes too much time (using a parallel timeout test), and this appears to work fine. So we are just going with the timeout test.
I believe this issue is now closed, and thank everyone for their help.