[ECOS] Serial and AT91

[Edgar Grimberg <edgar dot grimberg at rms dot ro>]

Hello,

My application is supposed to send some commands over the serial port to 
an external device, so I created some classes to handle the 
communication. The procedure is as follows:

1. lookup the device

   err = cyg_io_lookup( "/dev/ser1", &handle );

The return value is ENOERR

2. send some data

   err = cyg_io_write(handle, &send_buffer[0], &len);

3. drain the serial output

   cyg_uint32 len = 1;
   err = cyg_io_get_config(handle, 
CYG_IO_GET_CONFIG_SERIAL_OUTPUT_DRAIN, 0, &len);

4. call 2 & 3 again with different data

I monitor the serial port with a terminal program that shows me the hex 
code of the bytes sent. The first time I call 1, 2 and 3 and I see the 
desired result. The handle variable is global, so the second time, I 
call only 2 and 3. The application sends the data over the serial port 
OK (step 2), but hangs at 3. The size of the data is not big (10-20 
bytes / cycle).
The first thing to try was to skip step 3. Without it, the first 2 
cycles were OK, at the third one, no data is sent.
I debugged into the serial driver and found that, in 
at91_serial_start_xmit(serial_channel *chan), the condition 
(at91_chan->flags & SIFLG_XMIT_CONTINUE) == 0 is false. No matter how 
much I wait or how many times I try to send the data, this condition 
remains false.

If you have any hints, I will be very grateful.

Regards,
Edgar.


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