Arduino as ISP for ATTiny84

Following on in the same vein as my previous articles on Arduino as ISP for ATTiny85 IC, this article addresses the ATTin84. I refer you to the previous posts in the thread ATTiny85 thread for more information on plans, designs and etcetera, particularly Arduino as ISP for ATTiny85.

As I have mentioned in previous articles, there are very few differences between the 84 and the 85 in terms of pinouts. The arrangement and number of the pins are probably the most significant differences. The components required are virtually the same (you need a 14 pin DIP rather than an 8 pin … and obviously, you need an ATTiny84 IC).

Above is the pinout for the ATTiny85 IC and how it connects to the Arduino UNO. Below is the pinout for the ATTiny84 and how it connects to the Arduino UNO.

The differences between the two chips mean that there is some significant difference in the arrangement of the PCB that I designed for the ATTiny85 but the footprint is nearly identical and the ArduinoISP sketch that comes with the Arduino IDE needs no modification at all.

The Blink sketch also does not need modification from the already modified ATTiny85 version of the sketch, however, instead of connecting the LED to pin 5 (PB0), we are now connecting to pin 2 (PB0). Well … I still need to verify that once I’ve finished building the ISP and then breadboarded the ATTiny84 IC in the same test configuration as the previous article. But from my current reading, that should be just Jim Dandy.