[En-Nut-Discussion] Lost caracter with At91 UART0

Remi Bilodeau remi.bilodeau at gmail.com
Thu Dec 15 23:23:03 CET 2011

I try to upload a file to SD card using Ymodem protocol. It not work. After
displaying caracter count on a LCD screen, I find the UART lost around 30%
of the transmission.

I get the RX and TX buffer size, reporting 256 byte on RX and 64 on TX for
AT91SAM7S256 using this: 
_ioctl(_fileno(stdin), UART_GETRXBUFSIZ, &parm);

So UART0 seem buffed in theory. I get caracter through stdin and stdout
after reopen it in binary mode:
    freopen(DEV_UART0_NAME, "w+b", stdout);

     int c;
     do { c = getchar(); } while(c==EOF);

I receive only 81-83 byte or 132 bytes transmitted. I also try to send 16
bytes in a burst, and board receive 12-15 bytes only.

I don't think 115200bps is too fast for AT91 IRQ, anyone have a idea ??????


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