Thanks Tom.
I noticed an SH version that is listed as only having 256B RAM, rather than the 512B of the others. Not sure if that will have any bearing for our usage or programming.
That must be a typo - I don't believe the Atmel spec sheets say that. I'd trust the Atmel data on this. I'm using Atmel Studio 7.0 now, and Studio definitely sets the 85 (any 85) for 512 bytes RAM.
That makes more sense.
Are you planning on adding the "eswBrOutCfg" to the Repository?
Ohhh - actually I'm workin on it now - trying to add the n.n voltage level blinky feature. Didn't post it anywhere yet - gong slower to get it done than I thought.
I have a lock-out feature that works with the light OFF, do 2 quick clicks followed by an extra long hold -- it indicates lock-out by 4 quick blinks. Once locked-out, you have to do the same sequence to unlock it (2 quick clicks followed by a extra long hold).
For voltage monitoring, I want to do something similar. Plan is from OFF, do one click followed quickly by a long hold. Instead of strobe it will blink out the voltage (ex: for 4.1v, 4 blinks, pause, then 1 blink).
The lock-out feature so far is working great. The SupFire M2-Z (from MtnE) is a great light to test this on, since it has a very easily activated side switch plus it has bare threads so can't easily be locked out by twisting the loose the tailcap.
Note that enabling the AVR brown-out detector can at least double your parasitic battery drain. My SRK driver draws around 6 microamps without brown-out, over 30 microamps with brown out.
Brown out detection can also be disabled in software just before going to sleep. So you can keep the benefit but lose the power drain. Not sure if software BOD disable is available in the non-V attinys though. I’ve read someone say it’s not available.
If it helps, the code I used is copy-able. Not sure if it fits into your code easily, but it’s available if you want it. The files are tk-voltage.h, tk-calibration.h, and bistro.c; look for “BATTCHECK_VpT” to find the relevant sections.
The method I used is a table listing the raw ADC value followed by a packed number of blinks. So, two bytes per entry — 8 bits of ADC value, 3 bits of 1.0V blinks, 5 bits of 0.1V blinks. It iterates over that table to find the correct entry, unpacks the blink values, then, um, blinks. This was the most compact way I could think of to do it without sacrificing accuracy.
A smaller but less accurate method is to assume that 0.1V equals exactly 5.0 ADC units. This eliminates the table. But in my testing, it’s usually in the range of 4.4 to 4.8 ADC units per 0.1V, so it will skew as it gets farther from its origin value. This effect could be reduced by using the full 10 bits of ADC measurement and doing everything in 16-bit math, but that takes extra room too.
Yes - I should be able to use it. Just dnld'ed it. Thanks!
Funny, because "I think" my brownout support isn't actually turning ON brown out detection. I'm using fuses: E2/DF/FF and it still works fine. So guess I should have called it simply NOINIT or something equivalent? I believe I tried it disabled and enabled at 1.8V and notice no difference.
Didn't realize (or forgot) bout the extra parasitic drain. Is there anything more to it? Any other initialization I'm unaware of? I'm thinking the extra parasitic drain is coming from enabling it via the fuses?
I use this var in my code:
// OFF Time Detection
volatile byte noinit_decay __attribute__ ((section (".noinit")));
and it seems to work fine. I don't think there's any other initialization needed. This is in my main start-up code:
if (OffTimeEnable)
{
if (!noinit_decay)
{
// Indicates they did a short press, go to the next mode
next_mode(); // Will handle wrap around's
SaveConfig();
}
}
else
modeIdx = 0;
if (modeIdx == 0)
{
TCCR0A = PHASE;
blink(2);
}
// set noinit data for next boot
noinit_decay = 0; // will decay to non-zero after being off for a while
Never sure how you guys measures amps and voltages at so low of levels. Obviously my DMM can't go that low, so what's the method?
HP-3458A multimeter :party:
I have other meters that can measure down to femtoamps…
Hhhhhmmmmmm......Is Brown Out Detection needed for the memory decay trick? :~
BOD can be disabled in software but I don’t think it can be enabled in software if the fuses are set to BOD disable.
I'm thinking not because it seems to work, least for me...
Well, actually any volt-nut worth his salt needs three of them… man with two clocks never knows what time it is…
With a little patience, you can probably find a decent used one for less than $3000. I paid around $2400 for each of mine.
Proper calibration will probably set you back $500. I have the equipment to calibrate them (the SR104 10K resistor retails for $10K, you don’t want to know what the Fluke 732A/732B voltage references cost). There is a 3458A on Ebay right now that is up to $2000… calibrated… closes in 3 days.
That device looks cool! Still $66 USD, plus shipping I'm thinking but in a reasonable range. I gotta talk to my EE friends at work - I think they've done this without high end instruments. We got scopes, bench PS's, signal generators, flukes, etc., but don't think we have anything like that bench DMM -- not sure though.
Actually, any decent quality multimeter should be able to read down to micro-amps. I use Tektronix DMM912/914/916 meters. No longer made (?) but usually available on Ebay. With some patience you can probably snag one for less than $100.
seems lime you guys are speaking a totally foreign language lol ,this is way above my pay grade
Ok - think I got the new "n.n" battery status blinking working pretty well, thanks from T_K 
.
I've partially integrated in her new headers, and tweaked the "n.n" blinking. With the default values for blink timing/rates she had, I really couldn't figure it out. The values I'm using now are more like the blink timing/rate a NiteCore MH20 does on it's switch LED. I took out the period blinking and made the blinks longer/slower. I find it really nice this way. I used the PWM values for voltages T_K had defined, measured by Dale for the wight FET+1 driver. There were only 5 values defined for the original 1-5 blinks, so I filled in all the values in-between for the full 2.0v to 4.4v levels. I tested it on a few cells at various levels and seems to always be within 0.1v. Probably could be tweaked a little but seems very close and reliable.
So far I'm pretty happy with how it's working in the UI - from OFF, do 1 click followed quickly by a click&hold - then the first digit of the volts blinks out (2-4 times), then pauses, then the 2nd digit blinks (0-9 times). This repeats over and over with a 2 sec delay in-between. One click aborts it.