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Errata for AN3155

Question asked by Timm Knape on May 30, 2018



sorry, if this forum is the wrong place, but I did not find a better one :-)


In AN3155 (USART protocol used in the STM32 bootloader; DocID17066 Rev 7) on page 7 it is written:


2. for each command the host sends a byte and its complement (XOR = 0x00)


but if I XOR a byte and its complement I get 0xff as result, not 0x00.


I guess the correct meaning is restored if the XOR part is removed completely on checksums over a single byte. This also happens in byte 9 of the Read Memory Command (here the XOR should be replaced by complement). I do not know if any other documents are affected.


Sadly there is no contact in this document to address the problem directly.


Kind regards,