I have used these PCBs in an ISP programmer Shield for ‘Arduino UNO’. This programmer is compatible with the microcontrollers: ATmega 48/88/168 / 328P with 28 pins, and ATtiny 25/45/85 with 8 pins.

### TECHNICAL DETAILS / COMPONENTS

ISP programmer for ATmega / ATtiny

By making a small modification on the ATmega ISP programmer, we can make it compatible with ATtiny 8-pin micro-controllers. If we observe the distribution of the pins of the ATtiny microcontrollers, we can verify that if we inserted them in the socket of the ATmega programmer (28 pins), positioning the pin 1 of the ATtiny in pin 9 of the ISP programmer, we would hardly have to perform 2 changes in the circuit to be able to program them.

1) Pin 12 of the ISP programmer could be connected directly to the GND line, necessary to feed the ATtiny when we are programming it ... and the connection of pin 12 to GND of the ATmega doesn’t affect its programming.

 2) In pin 9 of the ISP programmer we will have to put a small switch, by means of the position of a jumper, to connect the quartz crystal when we have to program an ATmega. When we have to program an ATtiny, pin 9 of the socket will have to be joined with pin 1 (changing the position of the jumper) ... since pin 9 of the socket corresponds to pin 1 of ATtiny = Reset (see the diagram)

### LEARN / TOPIC / BUILD INSTRUCTIONS

For more details to build an ISP programmer for ATmega / ATtiny, you can see them on my Web page:

http://j-rpm.com/2018/07/shield-programador-isp-atmega-attiny-arduino/

...sorry, but it's in Spanish