measure analog signal period using timers on dragon12

Started by NG October 29, 2010
Dear All,

I am trying to measure analog signal's period on HCS12 using timers but the problem is according to my little experience, timers need to specify either falling or rising edge or both but in here this isn't the case, because i need to start the timer as soon as the signal value reaches a threshold value..

am in desperate need for any ideas

Thanks a lot

Maybe you can employ the A2D converter, and trigger the timer when you have reached the desired digital equivalent of the threshold? As far as the timing goes, you may have to take into account the added cycles between the time that the threshold is reached, and the time that the timer starts.

To: 6...
From: n...@yahoo.com
Date: Fri, 29 Oct 2010 10:29:40 +0000
Subject: [68HC12] measure analog signal period using timers on dragon12

Dear All,

I am trying to measure analog signal's period on HCS12 using timers but the problem is according to my little experience, timers need to specify either falling or rising edge or both but in here this isn't the case, because i need to start the timer as soon as the signal value reaches a threshold value..

am in desperate need for any ideas

Thanks a lot



What do u mean by employ ATD?

--- On Fri, 10/29/10, Jerry Fields wrote:

From: Jerry Fields
Subject: RE: [68HC12] measure analog signal period using timers on dragon12
To: 6...
Date: Friday, October 29, 2010, 5:39 PM
Maybe you can employ the A2D converter, and trigger the timer when you have reached the desired digital equivalent of the threshold? As far as the timing goes, you may have to take into account the added cycles between the time that the threshold is reached, and the time that the timer starts.




To: 6...
From: n...@yahoo.com
Date: Fri, 29 Oct 2010 10:29:40 +0000
Subject: [68HC12] measure analog signal period using timers on dragon12


Dear All,

I am trying to measure analog signal's period on HCS12 using timers but the problem is according to my little experience, timers need to specify either falling or rising edge or both but in here this isn't the case, because i need to start the timer as soon as the signal value reaches a threshold value..

am in desperate need for any ideas

Thanks a lot





Put a comparitor on the input to the timer and reference one side to
your signal and the other side to your reference.

Dave
NG wrote:
>
> Dear All,
>
> I am trying to measure analog signal's period on HCS12 using timers
> but the problem is according to my little experience, timers need to
> specify either falling or rising edge or both but in here this isn't
> the case, because i need to start the timer as soon as the signal
> value reaches a threshold value..
>
> am in desperate need for any ideas
>
> Thanks a lot

I just meant start and use the A2D converter on your HSC12. David may have a better idea though.

To: 6...
From: n...@yahoo.com
Date: Fri, 29 Oct 2010 06:51:05 -0700
Subject: RE: [68HC12] measure analog signal period using timers on dragon12

What do u mean by employ ATD?

--- On Fri, 10/29/10, Jerry Fields wrote:

From: Jerry Fields
Subject: RE: [68HC12] measure analog signal period using timers on dragon12
To: 6...
Date: Friday, October 29, 2010, 5:39 PM

Maybe you can employ the A2D converter, and trigger the timer when you have reached the desired digital equivalent of the threshold? As far as the timing goes, you may have to take into account the added cycles between the time that the threshold is reached, and the time that the timer starts.

To: 6...
From: n...@yahoo.com
Date: Fri, 29 Oct 2010 10:29:40 +0000
Subject: [68HC12] measure analog signal period using timers on dragon12

Dear All,

I am trying to measure analog signal's period on HCS12 using timers but the problem is according to my little experience, timers need to specify either falling or rising edge or both but in here this isn't the case, because i need to start the timer as soon as the signal value reaches a threshold value..

am in desperate need for any ideas

Thanks a lot



Thanks a lot
Really appreciate ur concern

--- On Fri, 10/29/10, Jerry Fields wrote:

From: Jerry Fields
Subject: RE: [68HC12] measure analog signal period using timers on dragon12
To: 6...
Date: Friday, October 29, 2010, 6:14 PM

I just meant start and use the A2D converter on your HSC12. David may have a better idea though.




To: 6...
From: n...@yahoo.com
Date: Fri, 29 Oct 2010 06:51:05 -0700
Subject: RE: [68HC12] measure analog signal period using timers on dragon12


What do u mean by employ ATD?

--- On Fri, 10/29/10, Jerry Fields wrote:

From: Jerry Fields
Subject: RE: [68HC12] measure analog signal period using timers on dragon12
To: 6...
Date: Friday, October 29, 2010, 5:39 PM

Maybe you can employ the A2D converter, and trigger the timer when you have reached the desired digital equivalent of the threshold? As far as the timing goes, you may have to take into account the added cycles between the time that the threshold is reached, and the time that the timer starts.

To: 6...
From: n...@yahoo.com
Date: Fri, 29 Oct 2010 10:29:40 +0000
Subject: [68HC12] measure analog signal period using timers on dragon12



Dear All,

I am trying to measure analog signal's period on HCS12 using timers but the problem is according to my little experience, timers need to specify either falling or rising edge or both but in here this isn't the case, because i need to start the timer as soon as the signal value reaches a threshold value..

am in desperate need for any ideas

Thanks a lot