Summary of Recover Bricked ATtiny Using Arduino as high voltage programmer
Summary: This article explains how to recover a bricked ATtiny caused by incorrect fuse settings (not physical damage) by using an Arduino as a High Voltage Programmer (HVP). It outlines why fuses can brick the chip, what a bricked condition means, and describes building a small circuit, uploading an Arduino sketch, and using Arduino pins to reset ATtiny fuses back to defaults so ISP programming works again.
Parts used in the Recover Bricked ATtiny Using Arduino as High Voltage Programmer:
- Arduino board (any compatible Arduino)
- ATtiny microcontroller (the bricked target)
- Small additional circuitry (discrete components for HVP interface)
- Wires/jumper cables
- Breadboard or perfboard for wiring
- USB cable to connect Arduino to PC
- Computer to upload Arduino sketch
Hi! Today I’ll explain you how to recover your bricked ATtiny microcontroller using your Arduino board. ATtinys are very popular due to their small form factor yet very powerful. While working with them you may accidentally brick the ATtiny. As arduino is extremely popular and really easy to use, I guess you have one or more lying on your work table. You don’t need to purchase a HVP (High Voltage Programmer), or search for an old PC with parallel port to recover ATtiny. Just build a small circuit, plug it into Arduino board, upload a sketch and you are good to go. So let’s start…
1) HOW ATTINY CAN BE BRICKED?
Actually, there are many reasons. But let me explain what I mean by “bricked”. If you’ve powered it with over voltage and fried it, well, it’s not “bricked” then, rather it’s roasted. Arduino and HVP have nothing to do with it. But, if your ATtiny stopped responding due to some wrong fuse settings, then it’s “Bricked” and hopefully we can recover it using Arduino as HVP. So another question is, what is fuse settings? Well, there are 3 bytes of permanent (by permanent I mean that they stick around after power goes out, but that you can change them as many times as you’d like) storage called the fuses. The fuses determine how the chip will act, whether it has a bootloader, what speed and voltage it likes to run at, etc. Note that despite being called ‘fuses’ they are re-settable and don’t have anything to do with protection from overpowering.
To learn more about fuses, simply google about AVR fuse. Or you may check this article .
There are various mistakes one can make in fuse settings that result in a bricked ATtiny. Most common of them are Disabling ISP Programming and Selecting Wrong Clock Source. If ISP programming is disabled in fuse settings, ATtiny will not respond to an ISP Programmer. It’s just like, you have a robot that does exactly what you order him and one day you order him “Stop listening to me!”. You know what’ll happen.
And if you set fuses that select wrong clock source than you are actually providing, it will stop responding until correct clock source is provided as per fuse settings which you either don’t know or forgot.
In these situations we can say ATtiny is “Bricked”.
2) HOW TO RECOVER IT?
Okay, now we need to learn how we can recover our ATtiny from bricked state. As we’ve already learned, ISP programmer can do nothing anymore until fuses are reset in default mode, hence we need a High Voltage Programmer. If you want to know how a HVP works, google about it.
Here we’ll make a High Voltage programmer using Arduino. Arduino has more than enough pins to simulate a HVP. A very minimal additional circuitry is required.
We’ll make the circuit, plug it in to Arduino, Upload sketch in Arduino and we are good to go. The HVP will reset the fuses of ATtiny to default one. So, the ATtiny will again respond to ISP programmer.
Considering you already have Arduino, the cost of rest of the circuitry will be very small.
For more detail: Recover Bricked ATtiny Using Arduino as high voltage programmer
- What does bricked mean for an ATtiny?
Bricked means the ATtiny stopped responding due to wrong fuse settings, not because it was physically damaged by overvoltage. - Can an Arduino be used to recover a bricked ATtiny?
Yes, Arduino can be used as a High Voltage Programmer to reset the ATtiny fuses to defaults. - Why do fuses brick an ATtiny?
Incorrect fuse settings can disable ISP programming or select a wrong clock source, causing the ATtiny to stop responding to normal programmers. - Do I need a commercial HVP to recover a bricked ATtiny?
No, you can build a small circuit and use an Arduino to act as a High Voltage Programmer instead of buying a HVP. - What is required to recover the ATtiny with Arduino?
You need an Arduino, a minimal additional circuit to interface as HVP, wires, and an uploaded sketch on the Arduino. - Will this method fix an ATtiny damaged by overvoltage?
No, an ATtiny physically damaged by overvoltage is considered roasted and cannot be recovered by HVP or Arduino. - What does resetting fuses accomplish?
Resetting fuses restores default settings so the ATtiny will respond again to ISP programmers. - Is the additional circuitry complex or expensive?
The article states the additional circuitry is minimal and low cost if you already have an Arduino.
