[En-Nut-Discussion] Possible BUG in ARM usart driver or crt routines

[Coleman Brumley]

I've not noticed this specific bug, but when I tried UART_SETTXBUFSIZE and
UART_SETRXBUFSIZE, I didn't get the expected results.

At the time, I just abandoned it because I didn't have the time to
investigate it.  

- Coleman

> -----Original Message-----
> From: en-nut-discussion-bounces at egnite.de [mailto:en-nut-discussion-
> bounces at egnite.de] On Behalf Of Ole Reinhardt
> Sent: Tuesday, September 01, 2009 11:26 AM
> To: Ethernut User Chat (English)
> Subject: [En-Nut-Discussion] Possible BUG in ARM usart driver or crt
> routines
> 
> Hi all,
> 
> I just discovered a strange bug, which I suppose to live anywhere in
> the
> usart code. Eventually it's arm specific, perhaps also in the main
> usart
> device driver code.
> 
> I'm using NutOS 4.6.0 with some extra bugfixes on an ethernut3 board.
> 
> In my special case I set the TX buffer size to a specific value. Let's
> say 8. When I then try to send out a larger data buffer with fwrite I
> recognise that packages of always 8 Bytes (same size as the usart tx
> buffer size) are repeated...
> 
> Example:
> 
> I'll send the following buffer:
> 
> "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
> 
> What is send out:
> 
> "abcdefgabcdefg..."
> 
> So the first 8 bytes are repeated twice, next followed by some more or
> less randomly new startpoint in the buffer.
> 
> My code looks like this:
> 
> [...]
> _ioctl(_fileno(uart0), UART_SETTXBUFSIZ, &txbuf_port0);
> [...]
> 
> int pos = 0;
> u_char buffer[100] =
> "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789äöüÄÖÜß?
> !
> \"§$%&/()={[]}\\,.-_<>|#'~+*'....";
> 
> do {
>     pos += fwrite(&buffer[pos], 1, 100 - pos, uart0);
> } while (pos < 100);
> 
> Has anybode noticed this behaviour too? Or have I missed any more
> recent
> bugfixes?
> 
> Regards,
> 
> Ole Reinhardt
> 
> 
> --
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> | Embedded-IT                                                 |
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