Hello Greg,
sorry for the delay, I have been busy on other projects. As said earlier, we use the start command over the serial interface to start the ADC. As indicated before, keeping the start pin high and increasing the delay between reset and first use of the device, the device reacts as expected.
We then made two seperate firmware versions in one of which the startpin was kept high, whilst the other version only has the increased time between reset and first use. After testing these versions we concluded that the problem was not solved by pulling the start pin high, but by increasing the time between the reset pulse and the first SPI command. According to figure 49 of the datasheet this should be 18 Tclk (Tclk=2,048 MHz). Increasing this time to 100 ms made the ADC react to SPI commands. A version in which this time was set to 90 us didn't fix the problem. So for some reason we must wait much longer before using the device after performing the reset, than specified in the datasheet. Is this an error in the datasheet, or are there other factors influencing this specification?
Kind regards,
Laurens Tromp