Bitbang the PA to do an OOK TX

[Jeffrey Ryan]

Hi,

I currently need a 2.4Ghz OOK tx and I'm looking into the NRF52840 DK. I know it is not supported but I'm thinking of doing bitbang and control the PA to do an OOK Tx.

I don't have much knowledge on RF so I need help from you guys if that would be possible and what are the things that I need to consider?

Thanks.

[ketiljo]

Hi Jeffrey

It depends on the datarate you're looking for here. It's possible to turn off the PA by flipping a bit in a register. If you write 0x2000 0000 into register 0x4000 176C, the PA will be switched off. Write 0x0 to turn it on again. The ramp up/down time should be ~1µs but i haven't verified this. 

Turning off the PA will set the output power to ~-30 dBm in 0 dBm mode, ~-60 dBm in 4 dBm mode and ~-50 dBm in 8 dBm mode. This is because the drive power is different. 

best regards,

Ketil Aas-Johansen

[Jeffrey Ryan]

Hi Ketil.

Thanks for this. The address that you mentioned is not indicated in the structure. It is under [reserved]. I'll get back to you once I have tested it. By the way, my target data rate is 5 kbps.

[ketiljo]

Hi Jeffrey

It's a internal register. 

cheers,

Ketil

[Jeffrey Ryan]

Hi Ketil. I just tested it and I was to able achieve my target data rate. Thanks for your help!

Regards,

Jeff