SNIU028D February 2016 – September 2020 UCD3138 , UCD3138064 , UCD3138064A , UCD3138128 , UCD3138A , UCD3138A64
Sometimes there are situations where development level firmware is required to start automatically with no PMBus interface command to start it. In this case, the program flash checksum must be programmed.
There may also be cases where flash security is desired for firmware under development. Again, the checksum must be programmed, preventing the device from going to ROM mode.
In this case, if reprogramming is desired, some kind of backdoor must be provided to clear the checksum. There are several backdoor techniques described below. Any one of them is adequate if used properly. For a robust and easy to use solution, however, the use of 2 or more backdoors is strongly suggested.
The techniques are: