High Voltage Serial Programming

If you need to make changes later on then high voltage programming is used to reset the fuses so the regular programmer can download the sketch again.

High voltage serial programming.

Half a year ago i restarted one of my old passions electronics. The avr dragon provides in system serial programming high voltage serial programming and parallel programming as well as jtag or debugwire emulation for parts with 32 kb of program memory or less. Hvsp requires 7 signals including power and ground as shown in this illustration. The arduino hv serial fuse programming sketch controls both the 12v to reset and the supply to the target to achieve this timing.

High voltage serial programming. The high voltage serial programming method applies 12v to the reset pin and a different set of programming commands in order to access the chip no matter what the fuse settings are. This project is created so that if i could revert the reset fuse change and flash via spi again. Here are some ways to generate that 12v signal depending on what components you have at hand.

As their name implies the high voltage serial and high voltage parallel programming techniques require a 12v signal. It should be noted that the current drawn from this signal is quite small. We provide the high voltage which usually is 12vdc for the flash devices and have total control over the chip programming. It employs the high voltage serial programming hvsp available for such devices.

The code in this project uses arduino nano to re program attiny85 microcontroller fuses to default values using the hvsp method. Atmel attiny datasheet chapter high voltage serial programming describes alternative way of programming attiny microcontroller. While i was expecting this huge leap in schematics and what a hobbyist can do nowadays i stil. With this mechanism it is possible to bring the mcu back to life.

Hvsp is the high voltage protocol for 8 and 14 pin attiny mcus. Atmel uses hvsp high voltage serial programming for the tiny avr family and high voltage parallel programming for the mega avr family. Connecting your standard arduino. Avr high voltage programming fuses rescue.

You could have unprogrammed the spien fuse programmed the rstdisbl fuse or whatever. I ve studied electronics in college but that happened during the middle age 20yrs ago. You can find the detailed programming algorithms in the all the avr data. For high voltage programming the timing of the power pin matters so it is software controlled through the svcc pin rather than.

A high voltage serial programmer can be used to reprogram the fuses. To enter and control the avr high voltage serial programming the supply to the target and the 12v to reset must be controlled with fairly critical timing.