https://devzone.nordicsemi.com/f/nordic-q-a/41018/sdk15-2-operational-issues-between-fds-and-ppi-adcHi Nordic, Does FDS affect PPI ADC acquisition when writing data? The test found that once the FDS is written to the data, the ADC data returned by the PPI ADC is fixed. 1.The acquired AD data is correct before the FDS write operation. 2.Afteren-USTelligent Community 13Thu, 29 Nov 2018 20:29:03 GMThttps://devzone.nordicsemi.com/thread/159631?ContentTypeID=1Thu, 29 Nov 2018 20:29:03 GMT137ad170-7792-4731-bb38-c0d22fbe4515:1d9b2ec9-41aa-4e96-9451-f8f0f25b867eKenneth<p>Hi,</p> <p>The CPU will be halted during the flash write operation, depending on how frequent the ecg_data occurs, it may not be able to service the interrupts between measurements. Maybe this is causing your program flow to misbehave. Can you check your ADC configuration has changed and/or if your event source for the PPI channel to the ADC task has changed?</p> <p>An FDS write operation may not take very long time if it&#39;s only an flash write operations that occurs (maybe tens of ~us range), but if the FDS write trigger an flash erase operation to be able to write, then the CPU may be halted for 100ms, which is very long time.</p> <p>Best regards,<br />Kenneth</p><div style="clear:both;"></div>