Using salvaged microcontrollers for Arduino projects - programming an ATMEGA8L with a TL866-II

Most Arduino sketches (programs) are small and do not take up the full 32K of the ATMEGA328P so why not use a smaller chip such as the ATMEGA8 for your standalone projects? Well you can do that using a TL866-II programmer instead of using the Arduino as ISP and putting the micro on a breadboard.

In my case I have a few salvaged / second hand microcontrollers that I want to use in my projects. They all had various clock speeds set and fuse lock bits set so I couldn't program them using the normal method of using an Arduino as ISP programmer and breadboarding the bare chip.

So I put them into a TL866 and reset the fuses to factory settings and erase the chips. Factory default means 1Mhz internal clock so this enables you to program a bootloader and set the fuse bits accordingly. Say for example you have a salvaged chip set for 12Mhz external clock. You won't be able to program it using the Arduino as ISP method; the chip needs "resetting" to be able to do this. Unless, of course you have the 12Mhz crystal too.

Lock bits are meant to stop anyone from downloading the code from a microcontroller to stop software piracy. They can also lock the processor out from being re-programmed and disable SPI programming. This depends on how the manufacturer chooses to set them in their products. A "high voltage programmer" such as the TL866 can reset some fuse bits making a salvaged microcontroller useable again.

In this example I use an ATMEGA8L with 8Mhz internal clock to replace an ATMEGA328P with 16Mhz external clock which was used in one of my standalone projects. I also show you how to flash a bootloader to a bare ATMEGA328P and set the fuse bits correctly.

Project this chip was used in https://youtu.be/1H4vz4Ukn-c

My blog https://www.adrian-smith31.co.uk/blog ... https://www.youtube.com/watch?v=ntWoLLowBEw