PIC18F1320 and wake-up

Hello, can anyone help please?

I have code that executes on wake-up from a port interrupt with the CPU 
clocked from the Internal oscillator block at 4 MHz. This works fine.

I've now got to add a function whereby every 15 minutes, the CPU wakes 
to send a signal to a remote unit to say 'I'm still working' and then 
revert to sleep. Low power consumption is a priority with this project.

The 16F684 (and others) have the Ultra Low-power Wake-up (ULPWU) module 
and I know I can implement this function externally but having looked 
through the data sheet I'm sure this can be done within the CPU, say, 
using the SEC_IDLE mode.

Enlightenment would be most welcome.

Cheers,
Simon

simon wrote:
> Hello, can anyone help please?
> 
> I have code that executes on wake-up from a port interrupt with the CPU 
> clocked from the Internal oscillator block at 4 MHz. This works fine.
> 
> I've now got to add a function whereby every 15 minutes, the CPU wakes 
> to send a signal to a remote unit to say 'I'm still working' and then 
> revert to sleep. Low power consumption is a priority with this project.
> 
> The 16F684 (and others) have the Ultra Low-power Wake-up (ULPWU) module 
> and I know I can implement this function externally but having looked 
> through the data sheet I'm sure this can be done within the CPU, say, 
> using the SEC_IDLE mode.
> 
> Enlightenment would be most welcome.
> 
> Cheers,
> Simon
Hi,

I've done several projects like this that need to save power.

1) Set up with WDT for the longest time (about 2 seconds).

2) Wake up every 2 seconds and count time - if not done, go back to sleep.

3) When you get to your count. Do the job.  Then go back to sleep.



-- 
Luhan Monat (luhanis 'at' yahoo 'dot' com)
"The future is not what it used to be..."
http://members.cox.net/berniekm

In message <MvEDd.15101$yW5.2222@fed1read02>, Luhan Monat <x@y.z> writes
>simon wrote:
>> Hello, can anyone help please?
>>  I have code that executes on wake-up from a port interrupt with the 
>>CPU  clocked from the Internal oscillator block at 4 MHz. This works 
>>fine.
>>  I've now got to add a function whereby every 15 minutes, the CPU 
>>wakes  to send a signal to a remote unit to say 'I'm still working' 
>>and then  revert to sleep. Low power consumption is a priority with 
>>this project.
>>  The 16F684 (and others) have the Ultra Low-power Wake-up (ULPWU) 
>>module  and I know I can implement this function externally but having 
>>looked  through the data sheet I'm sure this can be done within the 
>>CPU, say,  using the SEC_IDLE mode.
>>  Enlightenment would be most welcome.
>>  Cheers,
>> Simon
>Hi,
>
>I've done several projects like this that need to save power.
>
>1) Set up with WDT for the longest time (about 2 seconds).
>
>2) Wake up every 2 seconds and count time - if not done, go back to sleep.
>
>3) When you get to your count. Do the job.  Then go back to sleep.
>
>
>

Thanks,
Simon