How can I give the radio priority over everything else for doing easyDMA?

[David Fogelsong]

Not sure if this is possible or not, but it's beginning to look as though the radio may be corrupting packets, either when sending them or receiving them or both, because of possible contention with the CPU (and/or the CPU's access its program in flash memory).  I'd rather that the nRF52840 CPU just wait until the radio finishes its business before continuing.  Maybe one way to accomplish that would be to sleep the CPU, but short of that, can the radio just somehow be made the highest priority so that any easyDMA the radio does will always simply pre-empt other activities and never be starved?

[David Fogelsong]

I would like the CPU to remain productive (perhaps processing a packet already received) while it waits for the next packet to be received.  That is why I would rather not simply sleep the CPU.

[run_ar]

Hi,

As far as I can see from our documentation the priority of the AHB bus masters is static. However your application can avoid conflicts by using different AHB slaves for different tasks.

[David Fogelsong]

Here's the situation.  The programming code is in flash memory and is executing from there (fairly standard).  However, I am concerned that maybe accessing the flash memory in that way is causing a problem with the radio attempting to do easyDMA (I'm using Nordic's proprietary radio mode).  Is this a valid concern?  If so, how do I avoid the problem "by using different AHB slaves"?

[run_ar]

Ram (which is used by easyDMA) and flash is on different AHB slaves. The only thing you must consider is that the cpu will need some time between (or after a set of) packets to read the content from the radio buffers. For other HW peripherals you should check the AHB multilayer priorities and make sure they use a different AHB slave than the radio (if they run concurrently that is).