Attiny25/45/85 FW Development Thread

^ Yes, Tom E has already got his version of Star Momentary to full 13a functionality plus new features his previous version didn't have.

I personally think temp sensing is way overdue. We are building beasts these days that can be dangerous at times. This MCU with some programming talent won't make them completely safe, but it will make them a bit safer. Users will still have to exercise caution when using these lights, but at least a lapse in focus at the wrong time might be compensated by better thermal protection.

Tom E wrote:

I'm interested in trying to get the temp sensor to work - I'll work on it this weekend. I'll attempt to add a UI into the eswitch firmware to support the calibration.

This sounds like a very big challenge to do. Seems it will take the FW to a new level of complexity. Best wishes on the endeavor. I wish I had the skill to assist. I have a vague idea on the logic I would want, but turning that into code is another story. I can help with testing when you get to that point.

One important thing is driver's self heating,and it can course large errors.This is why LD-2 has external temp. sensor for flashlight temperature measurement and internal sensor is used for driver overheat protection.DD driver doesn't generate as much heat as linear(extra heat is generated in LED),but at for example at 10Amps(triple or similar setup),dissipated power in driver (let's say with 5mOhm resistance) would be 10^2*0.005=0.5Watts which is enough to increase driver PCB temperature by 10-15C in host without silicone cubes or similar stuff for better thermal conduction.

Useful document about internal temp. "indicator"(PIC but it's probably similar to atmel):

^ Very valid point led4power.

Been trying to design a OSH Park board that could be used to air wire an Attiny 13a, 25, 45, or 85 to an non-attiny based driver. The main purposes of the board are as follows:

  • Make it easier to swap in an Attiny MCU via airwires.
  • Protect the MCU pins from breakage by securing to pcb board via solder
  • Facilitate future FW flashes by keeping wires off the MCU pins
  • Help build a thermal path to the flashlight body for faster thermal response

It's taking me a lot of time because I am not handy with using Eagle yet. It still has a lot of problems.

The left picture is the top of the PCB with the Red areas representing were copper will be poured. The board will have a ground plane that covers the whole top of the board. This is to help facilitate a better thermal path to the flight body One could solder a copper strap or wire from the ground plane to the edge of the slaved driver. The copper strap could even go under the MCU for more effective contact.

The right picture below is the bottom of the board. The Blue areas represent where copper will be poured. The air wires can be attached all kinds of ways. Generally, one would probably use the Blue pads and route all the wires downward off the board. The vias can be used to help better mechanically secure the wires. There are pads so that one could add LVP resistors (R1 & R2) and a pad for an OTC capacitor.

Here is kind of an example. The airwired board in the below picture has an Attiny13a attached to the other side of it.

Is anyone else having the same problem I'm having, in re-programming the 45/85 - bricking them? I just tried an 85 and downloaded once fine, then tried the download immediately again, without reconnecting anything, and it's bricked now. The 45's lasted a while for a few downloads, and even worked fine with back to back downloads. I think what happens is the erasing works, and the programming fails, leaving the part useless.

This is becoming way too much a PIA - I can't get anything done. I'm looking into AVRDUDE now.

I am no expert by any means, but the -B option, set > 4, makes flashing stable for me when using an usbasp:

E.g.:

avrdude -c usbasp -p t13 -u -B 10 -Uflash:w:edc.hex -Ulfuse:w:0x79:m -Uhfuse:w:0xed:m

Thanks! I'll try anything - very desperate. I'm gonna be out of the 18 MCU's I have, soon, at this rate.

I need to get some FET+1 drivers with attiny25v/85v on them. I’m not sure I can swap the MCU on an existing board, but I have lots of ideas for better firmware on these better controllers.

PLEASE! Somebody send TK a driver board! PLEASE! :party:

TK - you need to order the proper P/N, but there is a 25V that match's the footprint precisely. The 45's and 85's are only available in a wider footprint, so you can bend or cut the legs. If done properly, they still can be programmed in place. Right now I have 45's, 25V's, and 85V's. I should post some pics. The wight 22mm FET+1 driver though fits the bigger footprint perfectly - it has extension pads for pins #1-4 and they match up perfect for the larger footprint.

The 25/45/85 Atmel datasheet has the info in sections 25 and 26. The "S8S1" package matches the 13A. And of course the "V" versions are the ones you want (10 Mhz max).

I'd send you some, but the download problems I'm having are a killer. Constantly removing/reflowing another MCU.... ugh. Gotta get this figured out.

Update: Hhmm, the 45's and 85v I thought I bricked I can actually still program. Just tried it with the -B 10 option, but also without the -B 10 option. I'm putting them in the clip bare. Wonder if there's a difference having them reflowed on a board? Maybe just bad contacts with the clip?

For testing purposes we could use a Fet + 1 7135 driver with a DIP-8 socket. Swap in attiny 13, 25, 85. If a particular chip is bricked or acting up just plug in a new one.

Anyone have a copy of a Fet + 1 7135 .brd? I’m tired / lazy at the moment.

Tom E wrote:

. . . Update: Hhmm, the 45's and 85v I thought I bricked I can actually still program. Just tried it with the -B 10 option, but also without the -B 10 option. I'm putting them in the clip bare. Wonder if there's a difference having them reflowed on a board? Maybe just bad contacts with the clip?

Other than the first 2 chips that I bricked immediately due to flashing bad fuses, I've been flashing the same chip. I would guess I have flashed it at least 8 times. I have had issues with getting good clip contact at times. I think it is due to my clip having to be opened to near it's max position. I didn't mention it earlier because it didn't sound like the same problem you were having.

EDIT: I find putting a little flux on solder wick works real good to pull off excess solder from pins when a clip can't hold on. The flux residue has to be scraped off the pins sometimes as it blocks contact.

[quote=Tom E]

One thing to look out for is the bits that set the ADC reference voltage… they are different on the Tiny13 and Tiny85. Another thing is the RC oscillator runs at different frequencies (8 vs 9.6 MHz?)

Yes, the ADC bit change is one of the lines of code changed. Also the clock difference is one of the other lines of code changed -- that makes two, plus the one reference that didn't compile and had to be changed, 3 total Smile.

I know these changes are in the source I posted - post #68 has the detail on the ADC change, post#70 has the link to the working project/code. It should be real simple to port any of our firmware versions - changes below. The other PIA is targeting the 25, 45 or 85. You have to change the AVRDude commands, as well as the project property in Atmel Studio for the targeted MCU. I've been swapping between 25, 45, and 85 - little annoying but not too bad. At least no source code changes are needed.

Clock rate change:

old: #define F_CPU 4800000UL

new: #define F_CPU 8000000UL

WatchDog Enable change:

old: WDTCR = (1<<WDTIE); // Enable interrupt every 16ms

new: WDTCR = (1<<WDIE); // Enable interrupt every 16ms (was 1<<WDTIE)

ADC_on:

old: ADMUX = (1 << REFS0) | (1 << ADLAR) | ADC_CHANNEL; // 1.1v reference, left-adjust, ADC1/PB2

new: ADMUX = (1 << REFS1) | (1 << ADLAR) | ADC_CHANNEL; // 1.1v reference, left-adjust, ADC1/PB2

I think that's everything. Of course the fuses are different, but again, the BAT files with the fuse definitions are in the google docs link.

Update: Sorry, didn't get a chance to try temp sensor support. But this eve, I did get brown out detection OFF time method working, and it's working in the eswitch version. So, I have firmware that is 1074 bytes running on a 45, about 26% code space used, and has a fully functioning power clicky switch support with mode memory and OFF time support, as well as full e-switch support! Best Of Both . Dang, this is getting easy...

Using that Fuse calculator too, I am using these fuse values to enable this combo of features:

-Ulfuse:w:0xE2:m -Uhfuse:w:0xdf:m -Uefuse:w:0xfe:m

Basically, I melded the STAR_NOINIT stuff into my eswitch version. This is where I ran out of code space before, and why I got into the 25/45/85's, specially since ImA4Wheelr got it basically up initially.

For the fuses, I analyzed what was done for the full brown-out detection, and made the same settings for the 45 family. With the Fuse Calculator, it was pretty easy to do.

My SRK driver firmware uses about 6K of Tiny85 code. I use the temperature sensor on the chip for thermal management. The sensor works well. The accuracy of each step in temperature vs ADC reading is very good. The absolute accuracy of the readings is not so good. They spec +/- 10C, but it seems to be a lot better than that. Mine were less than 3C off. Consistency between chips (at least from the same batch) was very good (<1C) I have a user calibration routine, but even uncalibrated it is quite usable.

Ohh - I didn't realize you had a full up working implementation, and with temp sensing. How did the firmware get so big? What all does it do?

Yes, yes… Inquiring minds want to know! :smiley:

So the 45 is the same footprint as the 13 or no?

^ Smallest you can get the 45 is SU package which is the same size as the Attiny13a SU. We use the Attiny13a SSU on most of our drivers. The SSU package is smaller than the SU package. You can, however, bend the SU pins inward to fit the SSU pads. Check out pictures in the OP.

If you want some logic for the temperature sensor check out JonnyC's MTN_Momentary temperature in his repository. It works great. Even though we can use an active external temperature sensor (my choice, where there is room) or a thermistor (cheap and small), on-MCU temperature sensor would work good enough for a lot of lights. You might as well be able to have it as an option if we're going to step up to the bigger MCUs.