What's the power consumption of a PIC chip in reset? - Electronic Circuits Projects Diagrams Free

2camjohn · 30th October 2009, 09:39 PM

Hey Guys.

I had a question that I couldnt work out using the datasheet.

Im currently designing something with the 16f630.
If I hold it in reset by pulling MCLR to ground, is the power consumption reduced like its in sleep mode?

If so, I could save a pin and a little code on my design which would be really handy.

Cheers
John

Sceadwian · 31st October 2009, 12:00 AM

No reset is not the same as sleep mode, not sure what the energy usage in reset is cause you're not really supposed to do that.

Mr RB · 31st October 2009, 07:45 AM

I believe it's very similar to sleep mode. The oscillator shuts down, the PORT pins go high impedance etc. The power consumption *should* be very similar to sleep mode. A quick test with a multimeter set to microamps would give a better answer...

kpatz · 31st October 2009, 07:01 PM

You can always program the MCLR pin to be an input with wake-on-pin change and implement the sleep in your code. Then you know the chip is actually "asleep" when you pull the pin low.

Sceadwian · 1st November 2009, 01:15 AM

If you do that you can't use ICSP can you?

kpatz · 1st November 2009, 02:00 AM

Quote:

Originally Posted by Sceadwian

If you do that you can't use ICSP can you?

Yes you can... even if the pin is programmed as an input instead of MCLR it still works as the Vpp pin (high voltage on it puts the chip into programming mode).

You just have to make sure not to put more than Vdd on it when used as an input, or the chip will enter programming mode in your application.

Sceadwian · 1st November 2009, 02:49 AM

High voltage programming is not ICSP programming. Especially not if that high voltage fries the sensor you were attaching to that input...

**Nigel Goodwin** · 1st November 2009, 11:22 AM

Quote:

Originally Posted by Sceadwian

High voltage programming is not ICSP programming. Especially not if that high voltage fries the sensor you were attaching to that input...

ICSP can be either high or low voltage programming, but in the VAST majority of cases it would be high voltage.

As with any ICSP design you need to design it properly, so that the programming system doesn't affect anything else.

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30th October 2009, 09:39 PM	#1
2camjohn	What's the power consumption of a PIC chip in reset? Hey Guys. I had a question that I couldnt work out using the datasheet. Im currently designing something with the 16f630. If I hold it in reset by pulling MCLR to ground, is the power consumption reduced like its in sleep mode? If so, I could save a pin and a little code on my design which would be really handy. Cheers John __________________ The first rule of mstechca club is do not talk about mstechca club. http://www.electro-tech-online.com/s...induser&u=1245 Last edited by 2camjohn; 30th October 2009 at 09:40 PM.

31st October 2009, 12:00 AM	#2
Sceadwian	No reset is not the same as sleep mode, not sure what the energy usage in reset is cause you're not really supposed to do that. __________________ "Because I be what I be. I would tell you what you want to know if I could, mum, but I be a cat, and no cat anywhere ever gave anyone a straight answer, har har."

31st October 2009, 07:45 AM	#3
Mr RB	I believe it's very similar to sleep mode. The oscillator shuts down, the PORT pins go high impedance etc. The power consumption should be very similar to sleep mode. A quick test with a multimeter set to microamps would give a better answer...

31st October 2009, 07:01 PM	#4
kpatz	You can always program the MCLR pin to be an input with wake-on-pin change and implement the sleep in your code. Then you know the chip is actually "asleep" when you pull the pin low.

1st November 2009, 01:15 AM	#5
Sceadwian	If you do that you can't use ICSP can you? __________________ "Because I be what I be. I would tell you what you want to know if I could, mum, but I be a cat, and no cat anywhere ever gave anyone a straight answer, har har."

1st November 2009, 02:49 AM	#7
Sceadwian	High voltage programming is not ICSP programming. Especially not if that high voltage fries the sensor you were attaching to that input... __________________ "Because I be what I be. I would tell you what you want to know if I could, mum, but I be a cat, and no cat anywhere ever gave anyone a straight answer, har har."