Degraded radio performance with QSPI

[kpreiss]

Hi,

We noted in the errata (Issue 133) that the radio performance is significantly degraded if the QSPI is enabled.  The suggested workarounds are to 1) lower Vdd to 1.7 to 2.0v or 2) only access QSPI when the radio is not operational.

In our application, we access the QSPI is memory-mapped mode every 500msec for tens of msec at a time resulting in a low duty cycle access time.  Are there uses cases which would allow both the radio and QSPI to function at the same time?  Would lowering the QSPI clock rate help?  Does the impact occur by simply enabling the QSPI peripheral without clocking?  If you have any information elaborating more on the cause of degradation that would be helpful.

Best,

Kurt

[Simonr]

Hi,

Unfortunately we didn't get any specific feedback that time, but this is what we're trying to characterize for you, I can't give you more than an estimate of "likely less than 3dB RX degradation across the channels" as of yet.

Sorry about the delay, but we're on it.

Best regards,

Simon

[Simonr]

Hi

Sorry about the late reply, but here's one more update:

In our own experiments, setting the drive strength to standard drive once in main() seems to do the trick, but we've had reports from customers where this still is an issue. So the surefire fix will have to be switching between high and standard drive, where you set it to high drive when flash is being accessed, and change it back to standard drive afterwards.

There should not be any radio degradation when the QSPI is running on 8Mhz and VDD = 3V. 

Best regards,

Simon