Has the DFEPACKET.PTR to be word-aligned?

[funkmaus]

Hello,

I am developing an nrf52811 BLE Direction Finding firmware.

During packet reception I would like to store the IQ samples on a uint8_t buffer right after some other (packet) data. I observed that this only works, if the part before the IQ data is a multiple of four bytes, i.e. if the DFEPACKET.PTR is word-aligned.

Before I am going to get crazy, let me ask: Am I right that the DFEPACKET.PTR has to be word-aligned? If so, it would be nice to have this information in the documentation.

Thanks in advance and best regards!

[Simonr]

Hi

That is correct. All pointers using EasyDMA must be word-aligned. As stated here, you can check out the Memory chapter to see which memories are available for EasyDMA.

Best regards,

Simon

[funkmaus]

Hi Simon,

Thank you for the quick reply.

Unfortunately, I do not see any statements regarding word alignment and EasyDMA in the documentation. The only bit of information regarding word alignment can be found in the Writing to flash section, which obviously doesn't apply here.

Contrary to your statement,

Simonr said:

All pointers using EasyDMA must be word-aligned

the description of the RADIO->PACKETPTR register states that "This address is a byte aligned RAM address". From this, not all EasyDMA pointers have to be word-aligned.

I am confused.

Best regards!