[Tinyos-help] Pulse detection in T2 TMote port

[André Miguel de Almeida Marrão Rodrigues]

Hi

I just sent it again because is seems the first one did not appear in the 
list.

André

----- Original Message ----- 
From: "André Miguel de Almeida Marrão Rodrigues" 
<andremiguelrodrigues at gmail.com>
To: <tinyos-help at Millennium.Berkeley.EDU>
Sent: Wednesday, November 21, 2007 10:15 PM
Subject: Pulse detection in T2 TMote port


> Hi
>
> I need do detect a digital 1ms width pulse in tmote port.
>
> I have modified the TEP 109 - Binary Pin-Connected Sensor in order to 
> detect the rising
> edge of the sinal (a square sinal with 1ms width) and that worked perfect 
> until the day
> that I get the node with my device near a WIFI router. Somehow noise 
> introduced in the
> circuit and there are a few false pulses.
>
> So now I want to detected the raising edge and the failing edge (using the 
> TEP 109 code) and
> measure the time between them, which should be arround 1ms. First things 
> become complicated
> because I'm not sure how to get the uS timer on TMote (so I use the ms 
> timer...) and perhaps most importante I'm not sure
> if I can process 2 interrupts (with the associated code on the driver and 
> on the program) in a 1ms timeframe.
>
> The code for the driver is the one from the TEP109 (user button); my code 
> is:
>
> event void Notify.notify(bool val) {
>
> uint32_t begin;
>
> uint32_t now;
>
>
> if (val == FALSE) {
>
>  call Timer1ms.startOneShot(2); //just to count the time from the raising 
> edge
>
> }
>
> else { //so it's a falling edge
>
> begin = call Timer1ms.gett0();
>
> now = call Timer1ms.getNow();
>
> if ((now - begin)< 2000 ){
>
> .......> a true pulse was detected
> Any advice or ideas are much appreciated.
>
> Regards,
>
> André Rodrigues
>
>