I am writing software to program a M360 via the bootloader using the protocol given in an-1160 and I have a couple of questions.
1. I can not find any minimum timing for the length of a RESET pulse. Are there any requirements for the RESET pin I need to follow?
2. An-1160 rev a page 3 - Checksum Field. The text and the formula both agree in defining the checksum as:
"The twos complement checksum is calculated from the summation of the hexadecimal values in the Number of Bytes field and
the hexadecimal values in the Data 1 to Data 255 fields (as many as exist)."
Now that doesn't make sense to me as it means that some of the fields (command and value) are not covered by the checksum. However if I create a packet corresponding to the example given for a reset packet and compute the checksum as suggested I get an answer that is different from the example. If I look at the checksum for the reset packet in the example it is clear that it is generated by simply summing the bytes from Number of Bytes to the end of the data and taking the 2s complement, which makes much more sense. Can you clarify which method is correct please?