Timer1 running in SLEEP mode

(instructions, reset, WDT, specifications...) PIC12F6xx, PIC16Fxxx, PIC16F6x, PIC16F7x

Timer1 running in SLEEP mode

Postby include12f675 » Tue Jul 03, 2018 5:21 pm

Hi forum,
sorry I'm not often frequenting the forum.
I commonly use a 12F675, but one thing I never learned. Is the timer1 running when the MCU is in a sleep state ?
I mean, is the internal clock feeding the timer during sleep time ?

Anyways. With a different case I've try to fed the clock with a 32 kHz quartz. Everything is fine and shows the running time, but only when is not yet in a sleep state. Once the command is performed nothing comes back alive.
So I still not having much luck with low power projects :(
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Re: Timer1 running in SLEEP mode

Postby Jorgef » Tue Jul 03, 2018 7:16 pm

Hi

Do you have the Timer1 configured for Synchronous or asynchronous operation.
As by the datasheet (section 5.4 page 35) the Timer1 can only operate in sleep when in Asynchronous mode ( T1CON./T1SYNC = 1).
Also the diagram in figure 5-1 (page 32) shows, at lower right, that the SLEEP signal afects the clock synchronization path, but not the oscilator neither the asynchronus clock path.

HIH
Best regards
Jorge
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Re: Timer1 running in SLEEP mode

Postby jtemples » Wed Jul 04, 2018 2:19 am

No clocks are running in sleep mode. If you want TMR1 to run in sleep mode, you must provide an external clock on GP5.
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Re: Timer1 running in SLEEP mode

Postby Jorgef » Wed Jul 04, 2018 11:57 am

Hi

The LP oscilator runs in sleep mode, with an 32.768KHz xtal across OSC1 (GP5) and OSC2 (GP4) pins, with relevant capacitors (18~22 pF) to ground, of course.
Also, as I mentioned before, it must be in asynch mode.
Best regards
Jorge
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Re: Timer1 running in SLEEP mode

Postby include12f675 » Tue Jul 10, 2018 2:04 pm

Sorry I'm late to reply. I was busy.
jtemples wrote:No clocks are running in sleep mode. If you want TMR1 to run in sleep mode, you must provide an external clock on GP5.

It might be the reason as I presumed. Otherwise the consumption in sleep mode wouldn't be below a uA ;)
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