How to identifier nRF51 SoC chip?

[wen jin zhang]

I try use the FICR information to identifier nRF51. but found some interesting staff when i read 0x10000000 first 16 bytes by SWD memory read. when I power on read. it return all 0x00. but i restart SWD debuger read again. it will return 0xAA 0x55 0xAA 0x55 0xAA 0x55 0xAA 0x55 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF

and CONFIGID also same.

do FICR be RTL? why could be changed, ? is there has fixed area can be used as identifier?

[Susheel Nuguru]

Not sure why you were reading 0x00's but the FICR is permanent device and calibration data tuned for each chip, it will/should not change.

[David García Polo]

Reading FICR area is the same as reading any flash on the device. Flash should be available when the SWD resources are available. Are you certain you actually read 0x0 and you do not get anything back in your SWD operation and then it is interpreted as a 0x0 instead? also, FICR is actually flash, so it does not change value.