nRF24L01+ SPI command problem

[gabbla]

Hi all,

I'm developing a custom board that is equipped with a nRF24L01+ (directly soldered on my PCB, no breakout). The board is equipped with a PIC32, that controls also the nRF. I'm writing a driver to do that, since there is a posix-like osal that run on the PIC.

Before going into details, these are the nRF connections:

Please note: currently L1, L2 and L3 are NOT mounted, since there are some problems with the external antenna tuneing. May this be a problem when writing/reading registers?

So, I'm trying to interface with the chip via SPI, but when I write a register and read it back, I got inconsisten value:

Here I previously wrote 0x25 to DYNPD (0x1C) register, and when I try to read it back I got a different value, 0xC5.There is a delay of 5mS between write and read.

Now the fun part: when I try to do the same operation with Arduino, on the same board (also with a commercial brekout), I manage to get the wrote value:

I tried with different SPI speed (1/2/4/6/10 MHz) but the result won't change.

The CE pin is always LOW in this stage.

Any idea?

Thanks,

Gabriele

[Kenneth]

Hello,

Seems the SPI configuration is wrong. The Arduino update MOSI on falling CLK edge (correct), while on PIC32 you update MOSI on rising edge (wrong).

Best regards,
Kenneth

[gabbla]

You are right, there was a wrong byte mask in my code, thanks a lot!

Gabriele