ZHCS429J March 2012 – November 2021 UCD3138
PRODUCTION DATA
The UCD3138 incorporates a 4k boot ROM. This boot ROM includes support for:
The Boot ROM is entered automatically on device reset. It initializes the device and then performs checksums on the Program FLASH. If the first 2 kB of program FLASH has a valid checksum, the program jumps to location 0 in the Program FLASH. This permits the use of a customer boot program. If the first checksum fails, it performs a checksum on the complete 32 kB of program flash. If this is valid, it also jumps to location 0 in the program flash. This permits full automated program memory checking, when there is no need for a custom boot program.
If neither checksum is valid, the Boot ROM stays in control, and accepts commands via the PMBus interface
These functions can be used to read and write to all memory locations in the UCD3138. Typically they are used to download a program to Program Flash, and to command its execution