This programmer isn’t widely popular as usually is easier to use the ISP programming method. But sometimes if you need to disable the RESET pin and use it as a regular pin instead or you want to disable or restore SPI fuses that control the ISP programming method, then you will need a High-Voltage parallel programmer of AVR microcontrollers.
One of the programmers available on the wide internet is HVProg. This is a redesign of STK500 but without development board components. This programmer supports all available AVR microcontrollers in every programming mode and is compatible with AVRstudio.
In HVProg there are two versions of programmer:
The Basic-Version has separate connectors(6 Pin ISP, 10 Pin ISP, Serial HV programming, Parallel HV programming); for the different programming modes, it needs a stabilized 5V and 12V input voltages.
- Schematic (Eagle-Format, Freeware 4.11): Download
- Schematic as gif-file (~400kb): Download
- Part list as txt: Download
The Advanced-Version needs an un-stabilized input voltage of at least 15V (AC or DC). It has a 6 Pin ISP and a 20pin connector for ISP, parallel, and serial high-voltage programming.
The original ATMEL firmware is available in .ebn format that is only supported by AvrProg (included in AvrStudio “.\Stk500\stk500.ebn”). When you have the original Avr910 programmer, you can directly flash the firmware in the At90s8535 or Mega8535.
- Connect the ISP programming adapter with your computer and the ISP port on the HVProg board;
- Mount the ‘Self-programming’ jumper to pin 1,2;
- Connect the power supply;
- Start AvrProg;
- Select ‘stk500.ebn’ and set the appropriate fuses (high-frequency crystal for Mega8535);
- Flash the firmware;
- Disconnect power supply and then the programming adapter;
- Mount the ‘Self-programming’ jumper back to pin 2,3.