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2010-03-30 by Robert Adsett
On 3/30/2010 5:45 PM, Steve Hodge wrote: > I have 2 Ohmite LVK series SMT current sense resistors that I was just about > to solder onto a pcb when I realized there are no markings on the actual > part to tell which are the two current terminals ("I" on the data sheet) and > whic
2010-03-30 by Steve Hodge
I have 2 Ohmite LVK series SMT current sense resistors that I was just about to solder onto a pcb when I realized there are no markings on the actual part to tell which are the two current terminals ("I" on the data sheet) and which are the two voltage sense terminals ("V"). I ha
2010-03-16 by Cat C
AAAAARGGGHHHH! Application Notes: is there anything they can't do? I'll be sure to read it when I have some time, right now I have to make up the lost time. Thank you Stefan. Cat > To: AVR-Chat@yahoogroups.com > From: yahoo@wsw-elektronik.de > Date: Tue, 16 Mar 2010 19:44:38 +000
2010-03-16 by _wsw_
Maybe the application note "AVR151-Setup and use of the SPI" would be of interrest? There is a whole chapter about the SS pin behaviour... Stefan --- In AVR-Chat@yahoogroups.com, Cat C wrote: > > > Thank you Bruce! > > That was IT (I think you mean SS though)! > > It's amazing ho
2010-03-16 by Terrance
No, however, I would use an AVR anyways. Not too hard to figure out what it needs to do once you read through his project. --- In AVR-Chat@yahoogroups.com, Zack Widup wrote: > > I guess he doesn't supply the source code for the PIC? > :-( > > Zack > > On Mon, Mar 15, 2010 at 10:3
2010-03-15 by Bruce Parham
Cat C wrote: > Thank you Bruce! > > That was IT (I think you mean SS though)! > Sorry yes, SS (Slave Select). It been a while since I looked at the data sheets. > It's amazing how... little things like this mess things up, and how lucky that you happened to look into this! > > I
2010-03-15 by Don Kinzer
--- In AVR-Chat@yahoogroups.com, Bruce Parham wrote: > The data sheet just says, if it's an input, it should be high to > keep the port in master mode. If the SS pin doesn't have a pullup on it, it could be floating low enough to trigger the Master-to-Slave transition between the
2010-03-15 by Cat C
Thank you Bruce! That was IT (I think you mean SS though)! It's amazing how... little things like this mess things up, and how lucky that you happened to look into this! I still don't understand why it happens, as I enable the SPI port after a long delay (even tried 1s) so the vo
2010-03-15 by Bruce Parham
Hi Cat, This may have already been asked and I missed it but, in your initialization code, do you set the CS pin to OUTPUT before or after you enable the SPI port? If it's done after, an initial low voltage on the pin may be forcing the SPI port into slave mode as soon as it's en
2010-03-15 by Zack Widup
I guess he doesn't supply the source code for the PIC? :-( Zack On Mon, Mar 15, 2010 at 10:38 AM, Terrance wrote: > > > Look here: http://www.angelfire.com/electronic/hayles/charge1.html > > I built a couple just like this...works very well. Good information on this > site, anywa
2010-03-15 by Terrance
Look here: http://www.angelfire.com/electronic/hayles/charge1.html I built a couple just like this...works very well. Good information on this site, anyways. --- In AVR-Chat@yahoogroups.com, "syberraith" wrote: > > I looked that up already. It's a 10C rise accompanied by a 10mV d
2010-03-15 by Jim Wagner
On Mar 14, 2010, at 8:11 PM, Robert Adsett wrote: > On 3/14/2010 8:58 PM, Cat C wrote: > > If you're gonna propose a reset chip, or other circuitry to get a > reset other ways, why? This works fine. > > I would recommend at least testing with a proper reset chip. > > Why? Simply
2010-03-15 by enkitec@gmail.com
On 15-Mar-10 00:11, Robert Adsett wrote: > > My other immediate suspicion in cases like this is initialization code. > Although given your experience with this processor family I cannot > imagine what you could be leaving out (and I have no suggestions to offer). > > My best sugg
2010-03-15 by David VanHorn
http://www.westmountainradio.com/CBA.htm On Sun, Mar 14, 2010 at 8:19 PM, Donald H wrote: > > > --- In AVR-Chat@yahoogroups.com, David VanHorn wrote: >> >> I can recommend the CBA-II for checking discharge capacity. >> > GOOGLE found: Results 1 - 10 of about 567,000 for CBA-II. >
2010-03-15 by Robert Adsett
On 3/14/2010 8:58 PM, Cat C wrote: > If you're gonna propose a reset chip, or other circuitry to get a reset other ways, why? This works fine. I would recommend at least testing with a proper reset chip. Why? Simply to try to narrow down the problem. Problems like this worry me,
2010-03-15 by Donald H
--- In AVR-Chat@yahoogroups.com, Cat C wrote: > > > The watchdog does it's job, it just happens to be the convenient way to have a reset a little while after a power up, if the SPI doesn't work. > I don't see any other way of "cleaning" the SPI. > It's not a simple communication
2010-03-15 by Donald H
--- In AVR-Chat@yahoogroups.com, David VanHorn wrote: > > I can recommend the CBA-II for checking discharge capacity. > GOOGLE found: Results 1 - 10 of about 567,000 for CBA-II. Did you have anyone in mind ? don
2010-03-15 by Cat C
The watchdog does it's job, it just happens to be the convenient way to have a reset a little while after a power up, if the SPI doesn't work. I don't see any other way of "cleaning" the SPI. It's not a simple communication timeout, it's a complicated one, and if I have 1000 SPI
2010-03-14 by David VanHorn
I can recommend the CBA-II for checking discharge capacity.
2010-03-14 by David VanHorn
According to an electrochemist I talked to with TI, you can also charge NIMH cells with a constant voltage with a current limit.. I don' t remember what the voltage per cell was though.
2010-03-14 by Dennis Clark
The watchdog is a pretty extreme way to get out of a communications timeout loop. Have you considered using a regular interrupt instead and clean up the SPI call in that? In my mind the doggy is best used to recover from going into the weeds, not from a simple communications time
2010-03-14 by Dennis Clark
Hi, Your method of checking voltage to determine cutoff would work somewhat for LiIon cells but not so well for NiMh. NiMh have a pretty flat discharge curve and their charge curve is best served by monitoring temperature rise, the "peak" voltage of an NiMh is subtle and not alwa
2010-03-14 by David VanHorn
On Sun, Mar 14, 2010 at 6:45 AM, syberraith wrote: > I just read Amtel's AVR-based Constant Current Supply app note, which left me wondering why would you prefer an external chip for the current regulation. What difficulty did you have with using just one chip? Codespace for one,
2010-03-14 by syberraith
Interesting... I read in the constant current app note that engineer for ControlTek also found the accuracy of the T15's ADC to be less than sufficient. So he used a external voltage reference and an opamp to get the current regulation of the PWM within 10%. I would ultimately li
2010-03-14 by syberraith
I looked that up already. It's a 10C rise accompanied by a 10mV drop, at least according to PowerStream datasheets. The simple voltage cutoff is actually for recharging disposable alkalines, cutoff at 10% of rated voltage. :) Fred --- In AVR-Chat@yahoogroups.com, Dennis Clark wro
2010-03-14 by Cat C
I kick the dog in the main loop, not the SPI loop, so that works fine when there are no problems. I WANT to get a reset if SPI doesn't work, so I DON'T want it to time out and exit. > To: AVR-Chat@yahoogroups.com > From: bob.paddock@gmail.com > Date: Sun, 14 Mar 2010 09:59:04 -04
2010-03-14 by Bob Paddock
On Sun, Mar 14, 2010 at 9:47 AM, erikc wrote: > > > > My understanding is that you have to feed the watchdog from time to > time in various parts of the programme, and that would include > software timer or stall loops as well. > http://www.ganssle.com/watchdogs.htm >You could fe
2010-03-14 by erikc
My understanding is that you have to feed the watchdog from time to time in various parts of the programme, and that would include software timer or stall loops as well. You could feed the watchdog from inside the counter loop. Then, you'd still get the timeout. Cat C wrote: > Th
2010-03-14 by syberraith
I just read Amtel's AVR-based Constant Current Supply app note, which left me wondering why would you prefer an external chip for the current regulation. What difficulty did you have with using just one chip? --- In AVR-Chat@yahoogroups.com, "syberraith" wrote: > > Yep, I've been
2010-03-14 by syberraith
I'm unsure if I want to go straight to my final design in one step. I might want to build a simple/limited version first. For my most simple version I have the current being regulated by a linear regulator, and all the controller needs to do it turn it off when the system reaches
2010-03-14 by syberraith
Yep, I've been looking at the Maxim charger chips that setup up to work with a uControllers. I have yet to run across any others. I have a Duracell 15 minute NIMH charger, and was wondering why it killed batteries so fast. After reading up on the charging methods for the differen
2010-03-14 by Cat C
That problem was caused by some code I "moved" from place to another but forgot to remove from the original, in effect copying instead of moving. The effect was complicated by interrupts, timers, etc; and the watchdog was only involved as an extra instruction to reset it in the m
2010-03-14 by Cat C
The voltage is fine once it's up, everything works after a reset. I tried the counter approach and it did tell me it timed out. However, I had to revert to no-timer so it gets stuck there so the watchdog doesn't get kicked, so I get a reset and then it works :-) Thanks, Cat > To:
2010-03-13 by John Samperi
At 05:27 AM 14/03/2010, you wrote: > From the data book: >/* Wait for empty transmit buffer */ >while ( !( UCSRnA & (1 >This has never worked for me, What do you mean? Never compiled or you have problem in transmitting? If the 1st case then have you replaced the n with a number f
2010-03-13 by Philippe Habib
I think that pretty much anything with an ADC would be enough. You could also get something with built in PWM so you could vary the charge voltage as the charge nears completion. The ATMega 16HVA, HVB, and 32HVA, HVB are designed to be chargers. You could also go with a general p
2010-03-13 by David VanHorn
I did this a while back, in a Tiny-26 with the AVR also doing the PWM constant current buck regulation. However, if I was to do it again today, I'd leave the current regulation to an external chip unless forced to do it this way for cost. I think that NIMH cells are probably the
2010-03-13 by erikc
My two cents: I find it helpful to provide the CPU with its very own voltage regulator (something like a 78L05 is sufficient) to be very helpful. Make sure to properly bypass the regulator on both input and output with at least 2 uF. Any routine I write that depends on a response
2010-03-13 by Donald H
--- In AVR-Chat@yahoogroups.com, "syberraith" wrote: > > I want to build a battery charger with a bit of intelligence, just a bit. > > I would like the charger to check the battery voltage every so often, one a minute at most, and if it has reached a set value, I would like the c
2010-03-13 by Andrew Mathison
I'll try and answer your queries:- >The changes were made because we weren't sure what a PC power supply outputs at power-up when the load on the 5V is only in the tens-hundreds milli-amps. Using a scope to determine that is >irrelevant, because another PSU might do something els
2010-03-13 by Ken Holt
Since Cat has been so persistent in trying to find real causality, it finally dawned on me that this might be the same as my USART transmit SW (assumed) problem on my mega168. From the data book: /* Wait for empty transmit buffer */ while ( !( UCSRnA & (1 > > It is near 4.5V, I d
2010-03-13 by syberraith
I want to build a battery charger with a bit of intelligence, just a bit. I would like the charger to check the battery voltage every so often, one a minute at most, and if it has reached a set value, I would like the charger to shut it self off. I would also like charging to com
2010-03-13 by Cat C
It is near 4.5V, I don't think exact value matters. Yes to small cap. I tried all levels of BOD with no difference. The other chips are varied in their power (voltage) requirements, I use level converters for some, but I don't see how that matters when the microcontroller is an S
2010-03-13 by John Samperi
At 09:53 AM 13/03/2010, you wrote: >4.5V It's complicated why :-) No, it makes sense. So you have about 0.5V-0.7V headroom which should be OK. Have you measured that it is 4.5V? ie is the R1/R2 divider calculated correctly for 4.5V and do you have the small cap there also? I woul
2010-03-13 by John Samperi
At 09:53 AM 13/03/2010, you wrote: >4.5V It's complicated why :-) No, it makes sense. So you have about 0.5V-0.7V headroom which should be OK. Have you measured that it is 4.5V? ie is the R1/R2 divider calculated correctly for 4.5V and do you have the small cap there also? I woul
2010-03-12 by Bob Paddock
> > > > I didn't the 1st time I used a LDO..... > > Not as much as I should have, HAHA. Seems OK tough, 100uF Tantalum 600mOhm > both on input and output. > Doesn't meet input requirements (should be 1uF in parallel... I don't think it oscillates or anything though. > See Linear
2010-03-12 by Cat C
4.5V It's complicated why :-) > To: AVR-Chat@yahoogroups.com > From: samperi@ampertronics.com.au > Date: Sat, 13 Mar 2010 08:52:43 +1100 > Subject: RE: [AVR-Chat] Re: Code stuck waiting for SPI transmission but only after power-up > > At 08:06 AM 13/03/2010, you wrote: > >5V (may
2010-03-12 by John Samperi
At 08:06 AM 13/03/2010, you wrote: >5V (maybe 5.2V) from PC PSU. So your target is less than 5V supply? Again I don't quite remember. (3.3V??) Regards John Samperi ******************************************************** Ampertronics Pty. Ltd. 11 Brokenwood Place Baulkham Hills,
2010-03-12 by Mike
Cat, I think a zener would need to be a mighty one to prevent spikes from a PSU that can provide maybe 15-30A. Current limit resistor first (300ma if I remember), then zener. The rest of it is curiosity, I'm more interested in how the SPI ONLY gets stuck under certain power condi
2010-03-12 by Ned Konz
On Wed, 2010-02-24 at 05:06 +0000, Donald H wrote: > > --- In AVR-Chat@yahoogroups.com, Leon Heller wrote: > > > > On 23/02/2010 23:00, rsimonus wrote: > > > I am curious about USB to serial db9 cable. I am planning to buy one. I want to know if any USB to serial 9pin cable which
2010-03-12 by Cat C
> > I assume you have 5 volt device (Micro)- but stated 4.5 v supplied to it.... This seems to low for anything to be >dependable..for a 5 volt device. It's a 2.7 - 5.5V > I was wondering what inspired you to protect the microcontroller from the big bad supply PC PSU with the lin