In this post I will explain how to program am ATTiny25/45/85 MCU. I really like the AVR chips, they are powerful, have enough flash and sram memory and have a lot of build in I/O devices. And the chips come in many sizes that all have the same MCU kernel, but a different number of I/O pins and different Flash/Sram sizes. The ATTiny85 is what I use the most, it has the most flash af the 25/45/85 series and it is rather cheap. The chip has 6 programmeble I/O pins and that is enough for a lot of things. It does not have a serial Uart but if you really need this you can use the software Uart. To program this chip you will need a programming environment, I use Visuals Studio PlatformIO and the old but decent Arduino IDE. Fot beginners I would recommend the Arduino IDE as it is foolproof and easier. With PlatformIO you can control much more (like all the fuse settings in binary format) but if you do something wrong you can get totally unusable bricked MCU chips. On this page I describe an Arduino Uno as ISP programmer.
Arduino Uno as ISP
I have bought a lot of Arduino programmers when I first started and I had a lot of problems with them especially the Chinese clones. Then I discovered the Arduino Uno as ISP and build several shields for 8, 14 , 20 and 28 pins AVR chips. Because all the different sizes of chips have their programming pins on different pins and need the power pins also connected, I build several shields. But they are cheap to make. Hier is the schematic of the shield I use for the ATTiny25/45/85 processor.
I use a standard prototype shield and a ZIF header for this (8 pins zif are hard to get so I use a bigger one and put tape on the unused pins), then first upload the Arduino as ISP scketch to the Arduino Uno. Select the AruidnoISP sketch from the examples and select Arduino Uno as board.



Connect the Arduino Uno using the USB cable and select the correct port in the Tools settings. Then use the Upload button to upload the ArduinoISP sketch to the Arduino Uno and your ISP programmer is ready.

I hope this was clear, if you got anything to add to this post then let me know, regards, Hein Pragt.






