Attiny25/45/85 FW Development Thread

Sorry, haven't been keeping up with this thread as of late. I'm still working on my version - calling it: eswBrOutCfg for now (e-switch BrownOut w/Configuration settings).

The last 85's I bought are these: http://www.mouser.com/Search/ProductDetail.aspx?R=ATTINY85V-10SHvirtualkey55660000virtualkey556-ATTINY85V-10SH. I think I went with the SH because I tried the SU in the previous buy, so I thought I might have a long shot at programming them more reliably, but that was before I figured out the ground problem in my SOIC-8 clip wiring.

SH are matte tin leads, while SU are NiPdAu leads. Not sure if one is better than the other for our application of soldering - I use lead based solder. I'd say go with the cheapest, but dunno -- one may be better... I see Richard is selling SU's for the 25 and 85 - great prices, but not the "V" lower voltage spec version.

The config settings are pretty awesome. I changed the order around, hopefully for the better. 1 thru 6 now makes a whole lot more sense. Here's what I'm using now:

Mode Set Order

Mode Count

Mode Percentages

Notes

1

1

full only

(full is always max FET, no 7135)

2

2

10-full

max 7135, max FET

3

3

5-35-full

5=1/2 7135, 35=mixed

4

4

2-10-40-full

10=max 7135, 40=mixed

5

5

2-5-10-40-full

10=max 7135, 40=mixed

6

6

TK BLF A6 7 mode

6 well evenly spread

7

3

10-35-full

10=max 7135, 35=mixed

8

4

TK BLF A6 4 mode

4 well evenly spread

Moon mode has been broken out separately to enable/disable it.

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…

So for just $5,500 for a refurbished unit, I too can make these measurements? Smile 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...

You can measure down to picoamps with a µCurrent adapter.

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