HI
For LPC55, only ROM version of DEVICE_ID0 is open to external.
ZhangJennie_0-1604907528917.png
Do you see below definition in SDK files? Please let me know the position, I will check.
PARTCONFIG
SRAM_SIZE
FLASH_SIZE
ROM_REV_MINOR
MODELNUM_EXTENTION
We can read part number from ROM for some of NXP LPC parts(for example LPC824). But LPC55 doesn't have this feature.
Best Regards
Jun Zhang