QSPI Behavior while executing XIP and accessing data not mapped to XIP.

[Jeff4BLE]

The QSPI can be used to read/write data via the DMA registers.

The QSPI interface is used with code is running from the XIP memory area.

Assuming the XIP and data areas are not overlapping, I assume switching between these two modes is a seamless operation. In other words, no configuration needed to switch between the two modes. Is this correct?

What happens to the system performance if the code in the XIP space begins a QSPI DMA data transfer and continues to execute from the XIP region? Is this even possible?

Is there any documented restriction of this kind of operation? And if so, where?

Thanks,

Jeff

[haakonsh]

"Assuming the XIP and data areas are not overlapping, I assume switching between these two modes is a seamless operation. In other words, no configuration needed to switch between the two modes. Is this correct?"

If you want to access the data region via QSPI then you need to use the QSPI driver to read/write. If that call is made from XIP region then you will have a really long wait state before the CPU can continue to execute. The DMA read has to complete before XIP gets access. The same the other way around: when an XIP access is in progress and DMA Read/Write started, the XIP access has to complete first.

There's no documentation for this scenario.