https://github.com/nikize/attiny85hvp
Simple HVP FUSE reset for ATTiny with Pro Micro
https://github.com/nikize/attiny85hvp
arduino attiny attiny85 high-voltage-serial-programming isp pro-micro
Last synced: 12 months ago
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Simple HVP FUSE reset for ATTiny with Pro Micro
- Host: GitHub
- URL: https://github.com/nikize/attiny85hvp
- Owner: NiKiZe
- Created: 2018-01-04T14:13:16.000Z (over 8 years ago)
- Default Branch: master
- Last Pushed: 2018-01-04T19:36:33.000Z (over 8 years ago)
- Last Synced: 2025-07-21T17:16:27.637Z (12 months ago)
- Topics: arduino, attiny, attiny85, high-voltage-serial-programming, isp, pro-micro
- Language: Arduino
- Homepage:
- Size: 1.19 MB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# AVR high-voltage serial programming for ATtiny
After possibly bricking your AtTiny, what do you do?
There is some different places on the web with information about what can be done and so on,
[such as this](https://github.com/tsaarni/avr-high-voltage-serial-programming)
But most of them use a bit complex schematics ...
You might be like me that you are lazy, don't have to much to work with and already have ISP header that you want to use.
So what is the easiest way to do this without to many connections and I found that I had some
[sparkfun level shifters](https://learn.sparkfun.com/tutorials/retired---using-the-logic-level-converter) laying around which could be used to get the 12V supply to reset.
So from that We can build our FUSE fixer without having to build a full circuit, this is what I ended up with:
I was already using the ISP header, so soldering on a extra wire to the ATTiny85, and conect it all togheter with jumper wires and it was done.
## Schematic
Basic schema for using a Pro Micro (Sparkfun or similar clone) and external 12v with level shifter
Note that level shifter connections are used differently
Shifter Pin | usage
--- | ---
Low side TX input | to Ground
Low side Power in (LV) | used as input and connected to pro micro signal pin
High side Power in (HV) | to 12V source
GND | not connected
This creates an inverter with high voltage output (but with a low 10K pull-up) pull-up might be to low, but worked for me
## Code for Pro Micro with above Schematics
See [ATTinyFuseReset.ino](ATTinyFuseReset/ATTinyFuseReset.ino) for actual code, run it and connect serial monitor and send anything to start FUSE reset
## Datasheet
Atmel
[ATtiny datasheet](http://www.atmel.com/images/atmel-2586-avr-8-bit-microcontroller-attiny25-attiny45-attiny85_datasheet.pdf)
chapter "High-voltage Serial Programming" is the method that is used here.
Normal serial programming method can be used again after running FUSE reset.