AVR ISP Programmer

thingiverse

Amtel AVR Microcontrollers come in a variety of configurations. The most widely recognized variant among Arduino users is the 28-pin ATMega328 model. However, AVR chips also come in 8-Pin, 14-Pin, 20-Pin, and 40-Pin packages. Fewer pins on a chip mean fewer IO ports are available. The Digispark board, an Arduino variant, uses a ATTiny85 Microcontroller with only five IO pins. Arduino boards (such as Uno, Mega, Digispark) load software from the Arduino IDE via the USB port due to the AVR Microcontroller being pre-programmed with a special piece of software called a bootloader. When purchasing a new AVR Microcontroller, it will be blank and cannot be programmed using the Arduino IDE for sketches. To program a blank AVR microcontroller, you need a specialized board such as the USBtinyISP programmer. The USBtinyISP allows downloading software from your PC via a USB cable and programming the chip. On the PC side, a program called Avrdude.exe is used to program AVR Microcontrollers using six pins. Unfortunately, due to different IC packages, the pins vary. A breadboard can be used to connect the output of the USBtinyISP to the AVR Microcontroller you want to program; however, this quickly becomes cumbersome. This build allows easy programming of all AVR DIL packages by containing a single zero insertion socket and six pin sockets wired for each variant of microcontroller. A 3D printed box holds the USBtinyISP board and custom PC board (Eagle files included). The custom PC board was created using the toner method.