[ECOS] Re: Question to 16x5x driver users

Gary Thomas gary@mlbassoc.com
Thu Jun 21 18:59:00 GMT 2007


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Alexander Aganichev wrote:
> On 6/19/07, Gary Thomas <gary@mlbassoc.com> wrote:
>> >> Am I right to make this change or I just missed another process that
>> >> should call xmt_char? I'm using LPC2294 based board and use this
>> >> driver for the UART1.
>> >
>> > It looks like eCos uses the usual UART sending procedure - enable
>> tx-empty
>> > (IER_XMT) interrupt and return, then the interrupt should trigger as
>> soon
>> > as tx is empty / tx fifo can take more data, and you write more data in
>> > your interrupt handler to the port. The fact it doesn't work for you
>> means
>> > most probably that you're not getting tx-empty interrupts, and,
>> perhaps,
>> > no UART interrupts at all.
>>
>> In my experience, this [incorrect] behaviour is not all that
>> uncommon.  I think that a CDL controlled option to enable this
>> initial "push" (although I'd call it 'priming') is the correct
>> fix.
>>
>> Alexander, please provide a proper patch, along with ChangeLog
>> entry to ecos-patches@ecos.sourceware.org.  We'll review and
>> apply as appropriate.
> 
> Just to make it clear: do you want me to just rename option from
> CYGPKG_IO_SERIAL_GENERIC_16X5X_XMIT_REQUIRE_PUSH to
> CYGPKG_IO_SERIAL_GENERIC_16X5X_XMIT_REQUIRE_PRIME, or make also a
> switchable option in ser_generic_16x5x.cdl and force it with requires
> { CYGPKG_IO_SERIAL_GENERIC_16X5X_XMIT_REQUIRE_PRIME == "true" }? I'm
> just not too much familiar with CDL, so first solution was easier for
> me :-)
> 

Yes, simply add the option CYGPKG_IO_SERIAL_GENERIC_16X5X_XMIT_REQUIRE_PRIME
to the generic CDL file (.../devs/serial/generic/16x5x/current/cdl/ser_generic_16x5x.cdl)
The default value should be 'false'.  You can put a requires statement in
the HAL CDL for your platform as necessary.

Once you have this, send a complete patch (using cvs diff - see the archives
for examples) to ecos-patches@ecos.sourceware.org.  We'll review it, suggest
changes, etc, and then incorporate it when it's ready.

Thanks for taking your time with this.


- --
- ------------------------------------------------------------
Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
- ------------------------------------------------------------
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