ColdFire/68K Microcontrollers and ProcessorsのトピックRe: Half Second Timer needed - read GPIO for every Half second

Half Second Timer needed - read GPIO for every Half second

TVNAIDU — Wed, 14 Oct 2009 02:10:27 GMT

Need to add smal pioece of code to read GPIO for every Half second code, any timer I can invoke from task to read fro every Half-second?.

appreciated.

Re: Half Second Timer needed - read GPIO for every Half second

admin — Wed, 14 Oct 2009 02:44:57 GMT

For interval of half a second, 32-bit timer needs to be used.

Alternatively, you can count the OS ticks (the default is 50 ms).

Re: Half Second Timer needed - read GPIO for every Half second

TVNAIDU — Wed, 14 Oct 2009 22:15:42 GMT

Thanks, can I crwate a separate task for this, in main function in for loop, can I use tk_sleep for Half second, that way, task collects data for every Half second.

task_main_fn()

{

for(; {

collect GPIO data and do process....

tk_sleep(half-second);

}

Re: Half Second Timer needed - read GPIO for every Half second

admin — Wed, 14 Oct 2009 22:26:52 GMT

Yes, it is the simplest solution: the dedicated task, which reads and processes GPIO and then sleeps for half a second.

Re: Half Second Timer needed - read GPIO for every Half second

TVNAIDU — Wed, 14 Oct 2009 23:09:46 GMT

Thanks Yevgeni. appreciated.

Re: Half Second Timer needed - read GPIO for every Half second

TVNAIDU — Thu, 15 Oct 2009 09:32:13 GMT

Hi Yevgeni:

I have to take 840 samples per second, if I keep for loop for 840 then if I keep tk_sleep, not sure when it finishes, for example I have to measure 24 receptacles instantaneous current and voltage for 840 samples per second, is there any way I can measure makesure 840 samples can take within one second, can I use times to happen 840 samples per second exactly without putting task in sleep using tk_sleep?

Re: Half Second Timer needed - read GPIO for every Half second

admin — Thu, 15 Oct 2009 14:32:50 GMT

TVNAIDU,

let discuss sampling the analog values in the separate thread.

Coukd you, please, open the new thread with the descriptive name?

Re: Half Second Timer needed - read GPIO for every Half second

TVNAIDU — Thu, 15 Oct 2009 18:06:50 GMT

Yes yevgenit, I opened another thread "Sampling of Analog values". Please take a look.

thanks.