When design programmer to programm C8051T616 device, how to gurantte the reliability?
Silabs Applications team strongly recommends customer to perform a margin read test on these devices during the programming verification step. This test reads back the relative strength of a programmed bit and indicates whether a bit is strongly programmed versus weakly programmed. In other words, if a normal OTP read returns 0x01 and the margin read returns 0x03, that means that bit 1 is actually weakly programmed. This would provide an early indication that a bit may not have been programmed correctly and ensure that all bits are strongly programmed when the device is soldered in the product.
To do this margin read:
1. Program the OTP as normal, but do not lock the code space.
2. Change the EPCTL register to 0xC0.
3. Read the byte of OTP. If it reads back the same as it was programmed, then the bits are strongly programmed. If it reads back incorrectly, then some of the bits are weakly programmed and a failure should be flagged.
4. Repeat steps 2-3 for the entire programming area.
5. (Optional) Lock the OTP by writing to the lock byte.