| DAVID | Posted: 19 Sep 2018, 05:02 PM |
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 I love mcus Member Posts: 237 Joined: 10-September 17 |
hi, i want to make a low power protect with the attiny85 and there are so many ways to accomplish this through the low power modes of the attiny but when it enters in to a deep sleep the only way to wake it up is reseting the mcu or using interrupts and that will be a problem in mi project. Is there a way to use the internal 128khz crystal oscillator for the clock? ------------- |
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| mit | Posted: 25 Sep 2018, 11:45 AM |
 yeah whatever Admin Posts: 566 Joined: 4-May 16 |
Oh hi, sorry for the slow response. Yeah you can set the ATtiny to use the 128khz oscillator as its main clock, if you go to the avr fuse calculator webpage and look at attiny85 some of the options in the drop down menu are for "WD. Osc. 128kHz". I guess you could combine this with the clk div8 fuse to go even slower. I never tried anything like that though, normally I find it's best to run fast, but then sleep for long periods. You can configure it to sleep until it's woken up by the watchdog timer which can be up to I think 16 seconds. ------------- |
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| DAVID | Posted: 25 Sep 2018, 11:04 PM |
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I love mcus Member Posts: 237 Joined: 10-September 17 |
well it seems to work but it is completely useless for my diy watch, i was hoping a current draw around 0.1 miliamps but i get the same current as if it was running at 1 mhz (around 20 miliamps at 5v) (and for using interfaces with the internal 128khz clock signal such as i2c it will be horribly slow) ------------- |
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| DAVID | Posted: 25 Sep 2018, 11:13 PM |
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I love mcus Member Posts: 237 Joined: 10-September 17 |
and i wanted to use a timer to count seconds since those are extremely precise and don´t wanted to use external devices like a RTC (Real Time Clock). the watchdog timer is used to wake up the mcu on a certain time but it is not precise enough to be use as a seconds counter ------------- |
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| alesterq1 | Posted: 8 Oct 2018, 07:26 AM |
 Member Posts: 1 Joined: 8-October 18 |
spam Last edit by mit at 8 Oct 2018, 11:53 AM ------------- |
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| kinzad9 | Posted: 15 Feb 2020, 05:53 PM |
 Member Posts: 1 Joined: 15-February 20 |
spam Last edit by mit at 15 Feb 2020, 06:06 PM ------------- |
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