Half a year ago i restarted one of my old passions electronics.
Atmega high voltage serial programming.
Hi that happened to my nano with atmega 328p using a usbasp programmer just checking the fuse settings to make a backup.
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.
This project is created so that if i could revert the reset fuse change and flash via spi again.
High voltage serial programming hvsp is mostly the backup mode on smaller avrs.
With this mechanism it is possible to bring the mcu back to life.
Compare with other high voltage programming options like atmel stk500 this programmer is simple to build less expensive and also easy to use with gui application over usb interface.
The recovery fuse programming process is easy.
Note that this is not to be confused w the high voltage parallel programming used for 20pin devices i e.
Avr high voltage programming fuses rescue.
Current version of avr hv support atmega series avr microcontrollers but it can also be used with attiny microcontrollers which having high voltage parallel.
An 8 pin avr package does not leave many unique signal combinations to place the avr into.
Atmel attiny datasheet chapter high voltage serial programming describes alternative way of programming attiny microcontroller.
The unified program and debug interface updi is a one wire interface for external programming and on chip debugging of newer attiny and atmega devices.
Avr hv allows programming reading verifying and configuring avr microcontrollers with its high voltage programming interface and it connected to pc using usb interface.
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You won t regret it.
But save yourself some time and invest in a programmer debugger that has hvpp high voltage parallel programming and hvsp high voltage serial programming.
I ve studied electronics in college but that happened during the middle age 20yrs ago.
If you don t have stk500 you can try to build your own avr high voltage programmer using arduino like jeff keyzer did.
Once the rstdisbl fuse is set you need a high voltage programmer like the stk500 which is costly to bring alive the chip.
If you really want to use high voltage serial programming to download a sketch then the instructions to implement a full blown programmer are documented in section 20 6 in the attiny85 datasheet.
Avr hv is high voltage parallel programmer for atmel avr series microcontrollers.
It employs the high voltage serial programming hvsp available for such devices.