Dear all,
i am experiencing a strange behavior on the u-boot ymodem protocol. I am running u-boot, (pulled from origin/head yesterday) on a mcf5307 based board. I am currently working to include this board/cpu as supported into u-boot.
cpu runs at 90Mhz (bus clock@45), baud rate 115200.
On an older u-boot (2011.09.00122), i was able to upload files through ymodem at 115200 without any issue.
Once pulled yesterday head, and installed on the board, i am no more able to upload files. U-boot times out when the first 128 bytes block is sent, and sends SYN (C) again, so i started some debugging on xyzmodem.c:
Protocol times-out here, from line 434
.... xyz.len = (c == SOH) ? 128 : 1024; xyz.bufp = xyz.pkt; for (i = 0; i < xyz.len; i++) { res = CYGACC_COMM_IF_GETC_TIMEOUT (*xyz.__chan, &c); ZM_DEBUG (zm_save (c)); if (res) { xyz.pkt[i] = c; } else { ZM_DEBUG (zm_dump (__LINE__)); ---->> return xyzModem_timeout; } }
Echoing received char back to PC, i see about 1 every 3 received chars seems lost somewhere, so the first 128bytes block is never completely received (time out).
I measured baudrate through oscilloscope, from PC to u-boot board, i have 115600 from u-boot board to PC, i have 117180 (still inside 2% tolerance)
Also verified timer/delay functions works properly in new u-boot build. As clients i used minicom and other, and have the same result.
So from a first look, seems the receive routine from line 434 is no more fast enough to receive the whole block. I moved speed down to 57600, upload works fine again.
What do you think about ?
Best Regards, Angelo Dureghello