nRF24LU1+: Erasing pages does not work

[gerhard]

I'm trying to erase the page 32 of a nRF24LU1+ via SPI (using a Bus Pirate).

What I did so far:

1. Display the first 16 bytes of content of page 32: 0x03 0x40 0x00 0x10
2. Enable writing flag (WREN): 0x06
3. Check if setting the write flag was successful: 0x05 0x01
4. Erase page nr. 32: 0x52 0x20
5. Display the first 16 bytes of content of page 32: 0x03 0x40 0x00 0x10

Result: The content is still there. Also the WREN flag is still enabled.

What did I do wrong? Did I miss something obvious? Is the chip really a nRF24LU1+? The marking says "NRF 0 LU1PA 1410NR".

Any help is welcome!

[Håkon Alseth]

Hi,

The device is an nRF24LU1+, but it's an OTP (one-time programmable) variant, which cannot be erased once programmed (you can only change a bit from '1' -> '0', not from '0' -> '1') This is indicated by the chip marking:

NRF 0 LU1PA 1410NR

Please see the nRF24LU1P-OTP datasheet, chapter 26, for detailed information about the chip marking: infocenter.nordicsemi.com/.../nRF24LU1P-OTP_PS_v1.0.pdf

Cheers, Håkon

[gerhard]

Thanks, Håkon! I knew I had missed something...