nrf52840 Anomaly 244 information

[jthlim]

I was looking for more information on Anomaly 244, which states:

Symptoms

Data transfer to and from external Flash with QSPI is corrupted.

Conditions

HF clock source is switching between HFXO and HFINT.

Consequences

Wrong data is read or written

Workaround

Ensure that the clock source is not switched during the QSPI operations. For example, force the HFXO enabled when SoftDevice is used by calling sd_clock_hfclk_request() after sd_softdevice_enable() during QSPI operations.

1. For the workaround, is it only necessary to call sd_clock_hfclk_request(), or do you need to also wait for hfclk to be active?

2. Does the anomaly occur with both HFXO -> HFINT and HFINT -> HFXO transitions? or just one of them?

3. Is there any way to reliably trigger this anomaly for testing purposes?

[Kenneth]

Hello,

1. You need to poll sd_clock_hfclk_is_running() until it returns true, or wait for the HFCLKSTARTED event.

2. Both can be problematic.

3. I guess adding advertisement with short interval while continuous read/write QSPI loop can trigger it.

Kenneth

[jthlim]

Thanks for the responses!