What is it?

This adapter allows you to use a computer-attached GPIO interface (such as a Bus Pirate or FTDI FT232H) to perform High-Voltage Serial Programming (HVSP) on 8- and 14-pin Atmel ATtiny chips. This differs from normal in-circuit programming because it allows access to more of the configuration fuses (for example; to disable the reset line, or enable debugWire). This isn't just a fuse resetting device though; it allows full access to all the programming features, such as flash and EEPROM programming. Also handy for resetting bad fuse combinations.

Note that to make use of this adapter, you will need either a Bus Pirate, an FTDI FT232H, or some other computer-attached GPIO interface; not supplied with this adapter. You will also need to use the "avr_hvsp" program supplied with the Device::Chip::AVR_HVSP CPAN module.

I'm also planning an additional board to connect on top to stand in place of the Bus Pirate, emulating the STK500v2 protocol (AVR068), allowing standard software such as avrdude to communicate with it directly. Watch this space...

Why did you make it?

I built this in order to make use of the "reset disable" fuse on the smaller ATtiny chips, allowing me to use the full range of 6 GPIO pins on an ATtiny85, or the full 12 pins on an ATtiny84. These also make it easy to work with debugWire because you can reprogram the flash without re-enabling SPI mode.

What makes it special?

Unlike any of the standard ICSP programmers available, this one work using HVSP so has access to extra fuse settings not available in ICSP. It also works regardless of the current fuse settings, allowing it to recover bad fuse settings. In comparison to similar "fuse doctor"-style products, this one is still a full programmer and allows complete reprogramming of all the memories, as well as resetting fuses.