UART in RTEMS

[Joel Sherrill]

On 08/11/2010 12:28 PM, Joris van Rantwijk wrote:
> Hi,
>
> On Wednesday 11 August 2010 18:50:18 João Rasta wrote:
>    
>> I'm using a LEON3 architecture with RTEMS. I can successfully open() the
>> UART device but i'm having transmission errors (erroneous packet data).
>> Accoording to rtems gaisler drivers doc rtems-gaisler-drivers-1.0.2.pdf i
>> need to register the driver with apbuart_register(&amba_conf) prior to start
>> TX/RX as well as to configure the driver with ioctl(), but i'm not sure. I
>> have checked that the baud rate is correclty set.
>>      
> I have only a little experience with the APBUART driver in RTEMS.
> It seemed to work fine, but the interface not so nice.
>
> To use it, I did something like:
>
> fd = open("/dev/apbuart1", O_RDWR);
> ioctl(fd, APBUART_SET_BAUDRATE, 38400);
> ioctl(fd, APBUART_START, NULL);
>
>    
>> Do i need to use such functions to get the UART working properly? Or open()
>> and cfsetospeed() for baudrate set are enough?
>>      
> cfsetospeed() has no effect, you need to use the ioctl().
>
> I'm unhappy that the driver does not use the standard termios interface.
> Also the call to apbuart_register() kills my stdin/stdout console.
> Also the driver works only with APBUART firmware cores that have a FIFO.
>
> We eventually designed a new APBUART driver, using the termios framework.
> If you like, I can send you our driver and you can give it a try.
>
>    
We would like to get the improvements back into the main tree.
> Greetings, Joris van Rantwijk.
>
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>    


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Joel Sherrill, Ph.D.             Director of Research&  Development
joel.sherrill at OARcorp.com        On-Line Applications Research
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