Hi,
Daniele Nicolodi wrote:
> Hello. In my application I need to read data from an ADC card in blocks
> of a given number of samples. For efficiency I'm using an mmapped buffer
> to exchange data with the ADC driver. I'm setting up the acquisition,
> and then calling a loop like this:
>
> unsigned int required = <compute required number of bytes>;
> unsigned int read = 0;
> while (1) {
> while (read < required) {
> read = a4l_pool(...);
> }
> process(buffer, ...);
> }
>
> However if I run this loop in a real time thread the tight while loop is
> an obvious cpu hog: the watchdog kicks in and kills the thread.
>
> There is not an analogy API that can be used to require a certain amount
> of data to the ADC driver. How can I code this loop to let other
> processes to run?
As a matter of fact, there is something in the API which could have
helped you in an unmapped configuration. If you set the flag
A4L_CMD_BULK in the field "flags" of the command structure, a call to
a4l_async_read() only returns when the data size specified as argument
is available.
Unfortunately, I have not done the same thing with a4l_poll, I might
have added the requested size as an additional argument to a4l_poll.
Any idea on how to extend the API without breaking it ?
>
> Thanks. Cheers,
> --
> Daniele
>
> _______________________________________________
> Xenomai-help mailing list
> Xenomai-help@gna.org
> https://mail.gna.org/listinfo/xenomai-help
--
Alexis.
_______________________________________________
Xenomai-help mailing list
Xenomai-help@gna.org
https://mail.gna.org/listinfo/xenomai-help
