On Tue, Feb 06, 2024 at 09:05:33PM +0800, jihongbin wrote: > It may be that there are relatively few people using this function, or the > length of the transmitted data is less than 128byte * 255 byte, so the > triggering conditions for the above problems are not encountered; > > I actually discovered this problem during testing. Continuous transmission > always fails at block 255. > > The following is the protocol's definition of blk cblk, cblk = 255 - blk > The original content of the agreement > (https://www.menie.org/georges/embedded/xmodem_specification.html) is as > follows: > -------- 3. MESSAGE BLOCK LEVEL PROTOCOL > Each block of the transfer looks like: > <SOH><blk #><255-blk #><--128 data bytes--><cksum> > in which: > <SOH> = 01 hex > <blk #> = binary number, starts at 01 increments by 1, and > wraps 0FFH to 00H (not to 01) > <255-blk #> = blk # after going thru 8080 "CMA" instr, i.e. > each bit complemented in the 8-bit block number. > Formally, this is the "ones complement". > > <cksum> = the sum of the data bytes only. Toss any carry.
Please repost the patch with these kind of details in the commit message, thanks. -- Tom
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