Hi @ThomasSPana
Given that it returns NULL, this likely indicates a CRC fault or a hardware setup issue with the CRC module on the LPC5536.
The LPC5536 has a built-in hardware CRC module, but it may need to be initialized or enabled before use. So you needs to be set to enable the CRC peripheral.
You can refer to CRC examples about how to use CRC.
BR
Hang