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2004-04-05 by jay marante
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2004-04-05 by David VanHorn
At 06:56 AM 4/5/2004 -0700, jay marante wrote: >Hi! > >I want to put the mega16 in a power-save mode but i cant get it done. anu sample C codes? i want it so badly coz my system comsumes so much power from the 9V battery. i think it wont even last a day. First off, how are you doing your voltage regulation? When moderate currents are flowing, switchers are more efficient. When the current is very small, linear regs win. On sleeping, you need to set your external I/O up to the appropriate states (only you can figure that) and then worry about the processor. Turning off timers that you don't need, shutting down analog ref and A/D. In the M128, you can program the Xdiv register to slow the clock down quite a lot. In all the megas, you can program the CKOPT fuse to use the Vittoz oscillator, but you'd better do some careful design there, to avoid problems. Of course you need a mechanism to come out of low power mode, like an interrupt, or ... ?
2004-04-05 by jay marante
im using max883 as a linear regulator. its output is about 200-250mA of current. how will i code the power-save mode in ICCAVR? thanks. -jay David VanHorn <dvanhorn@cedar.net> wrote: At 06:56 AM 4/5/2004 -0700, jay marante wrote: >Hi! > >I want to put the mega16 in a power-save mode but i cant get it done. anu sample C codes? i want it so badly coz my system comsumes so much power from the 9V battery. i think it wont even last a day. First off, how are you doing your voltage regulation? When moderate currents are flowing, switchers are more efficient. When the current is very small, linear regs win. On sleeping, you need to set your external I/O up to the appropriate states (only you can figure that) and then worry about the processor. Turning off timers that you don't need, shutting down analog ref and A/D. In the M128, you can program the Xdiv register to slow the clock down quite a lot. In all the megas, you can program the CKOPT fuse to use the Vittoz oscillator, but you'd better do some careful design there, to avoid problems. Of course you need a mechanism to come out of low power mode, like an interrupt, or ... ? --------------------------------- Yahoo! Groups Links To visit your group on the web, go to: http://groups.yahoo.com/group/AVR-Chat/ To unsubscribe from this group, send an email to: AVR-Chat-unsubscribe@yahoogroups.com Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service. --------------------------------- Do you Yahoo!? Yahoo! Small Business $15K Web Design Giveaway - Enter today
2004-04-05 by David VanHorn
At 07:37 AM 4/5/2004 -0700, jay marante wrote: >im using max883 as a linear regulator. its output is about 200-250mA of current. Your system draws that much? If so, you seriously need a switcher. The linear is wasting about 40% of the power available, and a switcher will not be more than 10%, and could reach 2% for an ideal design. >how will i code the power-save mode in ICCAVR? Complicated subject. You have to determine how to configure the I/O ports so that the external stuff draws as little power as possible, then set the ports up that way. You'll also have to pay attention to sequencing as you go to sleep, and as you wake up agian. There may be things in your externals that need to be done in a certain order to avoid damage, or large power draw. In the chip, it's "simply" a matter of shutting off peripherals you aren't using, lowering clock speeds to minimum, and activating sleep. The sleep instruction has to be preceeded by a sleep enable. If course you also have to provide a wakeup mechanism. It's not a simple thing. Can you describe the system in more detail?
2004-04-05 by LightYearCS
Just wanted to add to this. In this day and age, most if not almost all switching regulators will win out over linear types. One exception is the LDO linear regulator but then you need to have your input voltage to be very close to your output voltage for there to be any real efficiency. I've done extensive research on DC-DC converters, mostly converting from 3.6 volts to 5 volts. The parts I'm using are 96% efficient. Some amazing stuff out there. Barry
-----Original Message----- From: David VanHorn [mailto:dvanhorn@cedar.net] Sent: Monday, April 05, 2004 7:17 AM Subject: Re: [AVR-Chat] sleep mode in mega16 At 06:56 AM 4/5/2004 -0700, jay marante wrote: >Hi! > >I want to put the mega16 in a power-save mode but i cant get it done. anu sample C codes? i want it so badly coz my system comsumes so much power from the 9V battery. i think it wont even last a day. First off, how are you doing your voltage regulation? When moderate currents are flowing, switchers are more efficient. When the current is very small, linear regs win. On sleeping, you need to set your external I/O up to the appropriate states (only you can figure that) and then worry about the processor. Turning off timers that you don't need, shutting down analog ref and A/D. In the M128, you can program the Xdiv register to slow the clock down quite a lot. In all the megas, you can program the CKOPT fuse to use the Vittoz oscillator, but you'd better do some careful design there, to avoid problems. Of course you need a mechanism to come out of low power mode, like an interrupt, or ... ? Yahoo! Groups Links
2004-04-05 by LightYearCS
Yeah yeah like David said... Look for a "dc-dc buck converter." Check out Texas Instruments. They have an excellent sample policy and you can get samples right on line. You can get more samples if you call in. Typically, you can get 5 online or 20 (max) if you call in. Don't abuse the privilege please, I rely on this sampling service and would be upset if policy changed.
-----Original Message----- From: David VanHorn [mailto:dvanhorn@cedar.net] Sent: Monday, April 05, 2004 8:11 AM Subject: Re: [AVR-Chat] sleep mode in mega16 At 07:37 AM 4/5/2004 -0700, jay marante wrote: >im using max883 as a linear regulator. its output is about 200-250mA of current. Your system draws that much? If so, you seriously need a switcher. The linear is wasting about 40% of the power available, and a switcher will not be more than 10%, and could reach 2% for an ideal design. >how will i code the power-save mode in ICCAVR? Complicated subject. You have to determine how to configure the I/O ports so that the external stuff draws as little power as possible, then set the ports up that way. You'll also have to pay attention to sequencing as you go to sleep, and as you wake up agian. There may be things in your externals that need to be done in a certain order to avoid damage, or large power draw. In the chip, it's "simply" a matter of shutting off peripherals you aren't using, lowering clock speeds to minimum, and activating sleep. The sleep instruction has to be preceeded by a sleep enable. If course you also have to provide a wakeup mechanism. It's not a simple thing. Can you describe the system in more detail? Yahoo! Groups Links
2004-04-05 by Larry Barello
The mega16 in max power mode consumes only 40ma. Simply putting it into IDLE mode between interrupts will drop the consumption to 5 or so ma. If you circuit is drawing 250ma then the vast bulk of the current draw is from something OTHER than the CPU. Read about the sleep modes in the data sheet. You set two bits in the MCUCR and then execute the "sleep" instruction. Interrupts will bring you out of the sleep. Turning off peripherals (Analog comparator, ADC) will save you about 1ma max, if even that.
-----Original Message----- From: jay marante [mailto:jaythesis@yahoo.com] Sent: Monday, April 05, 2004 7:38 AM To: AVR-Chat@yahoogroups.com Subject: Re: [AVR-Chat] sleep mode in mega16 im using max883 as a linear regulator. its output is about 200-250mA of current. how will i code the power-save mode in ICCAVR? thanks. -jay David VanHorn <dvanhorn@cedar.net> wrote: At 06:56 AM 4/5/2004 -0700, jay marante wrote: >Hi! > >I want to put the mega16 in a power-save mode but i cant get it done. anu sample C codes? i want it so badly coz my system comsumes so much power from the 9V battery. i think it wont even last a day. First off, how are you doing your voltage regulation? When moderate currents are flowing, switchers are more efficient. When the current is very small, linear regs win. On sleeping, you need to set your external I/O up to the appropriate states (only you can figure that) and then worry about the processor. Turning off timers that you don't need, shutting down analog ref and A/D. In the M128, you can program the Xdiv register to slow the clock down quite a lot. In all the megas, you can program the CKOPT fuse to use the Vittoz oscillator, but you'd better do some careful design there, to avoid problems. Of course you need a mechanism to come out of low power mode, like an interrupt, or ... ? ---------------------------------------------------------------------------- ---- Do you Yahoo!? Yahoo! Small Business $15K Web Design Giveaway - Enter today ---------------------------------------------------------------------------- ---- Yahoo! Groups Links a.. To visit your group on the web, go to: http://groups.yahoo.com/group/AVR-Chat/ b.. To unsubscribe from this group, send an email to: AVR-Chat-unsubscribe@yahoogroups.com c.. Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
2004-04-05 by Phil
If you really are pulling 250 mA with a simple design and a linear Vreg, make sure you have a 0.1uF bypass cap between the V input and ground as called out on the datasheet. Its easy enough to overlook when putting something together. At 250mA your vreg should be very hot or have a mondo heatsink. --- In AVR-Chat@yahoogroups.com, "Larry Barello" <yahoo@b...> wrote: > The mega16 in max power mode consumes only 40ma. Simply putting it into > IDLE mode between interrupts will drop the consumption to 5 or so ma. If > you circuit is drawing 250ma then the vast bulk of the current draw is from > something OTHER than the CPU. > > Read about the sleep modes in the data sheet. You set two bits in the MCUCR > and then execute the "sleep" instruction. Interrupts will bring you out of > the sleep. Turning off peripherals (Analog comparator, ADC) will save you > about 1ma max, if even that. > > > -----Original Message----- > From: jay marante [mailto:jaythesis@y...] > Sent: Monday, April 05, 2004 7:38 AM > To: AVR-Chat@yahoogroups.com > Subject: Re: [AVR-Chat] sleep mode in mega16 > > > im using max883 as a linear regulator. its output is about 200- 250mA of > current. > > how will i code the power-save mode in ICCAVR? > > thanks. > > -jay > > David VanHorn <dvanhorn@c...> wrote: > At 06:56 AM 4/5/2004 -0700, jay marante wrote: > > >Hi! > > > >I want to put the mega16 in a power-save mode but i cant get it done. anu > sample C codes? i want it so badly coz my system comsumes so much power from > the 9V battery. i think it wont even last a day. > > > First off, how are you doing your voltage regulation? > When moderate currents are flowing, switchers are more efficient. > When the current is very small, linear regs win. > > > On sleeping, you need to set your external I/O up to the appropriate > states (only you can figure that) and then worry about the processor. > > Turning off timers that you don't need, shutting down analog ref and A/D. > In the M128, you can program the Xdiv register to slow the clock down quite > a lot. In all the megas, you can program the CKOPT fuse to use the Vittoz > oscillator, but you'd better do some careful design there, to avoid > problems. > > Of course you need a mechanism to come out of low power mode, like an > interrupt, or ... ? > > > > > -------------------------------------------------------------------- -------- > ---- > Do you Yahoo!? > Yahoo! Small Business $15K Web Design Giveaway - Enter today > > -------------------------------------------------------------------- -------- > ---- > Yahoo! Groups Links > > a.. To visit your group on the web, go to: > http://groups.yahoo.com/group/AVR-Chat/ > > b.. To unsubscribe from this group, send an email to: > AVR-Chat-unsubscribe@yahoogroups.com > > c.. Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.