AVR ATTiny programming adapter

This article describes a simple adapter for programming 8 and 14 pin DIP AVR ATTINY chips using an ISP programmer.

I find that a lot of my projects are based on 8 and 14 pin DIP AVR ATTINY chips, and having developed ATB - a bootloader for AVR Tiny microcontrollers there is no need for an AVR ISP connector on the projects as they will be updated using the single or two wire ATB interface.

Design

The device is constructed on Veroboard using:

•  a 28pin ZIF socket;
•  a 6 pin ISP connector;
• a three pin 5V regulator and filter capacitors;
• a power connector, and;
• a socketed ATTiny25 with fuses set for internal oscillator and output on the CO pin.

The ZIF28 socket accommodates a 8 pin ATTINY at the lever end, and a 14 pin ATTINY at the other end, notches to the lever end in both cases. The two chip positions do not share any pins, so it is possible to wire both pin sets without conflict.

The power and ISP signals are multipled across the connectors.

The ATTiny25 is a clock generator for devices set for crystal or external clock. The clock out of the chip is routed via a SIP shunt to the CI pins of the ZIF socket. (The ATTiny25 clock generator flash is erased, no code is required.)

Implementation

Fig 1: Top view

Fig 1 shows the top view of the adapter with a 14pin DIP in the ZIF socket. 

Fig 2: Copper side

Fig 2 shows the copper side of the board. There is the inevitable mistake where track was drilled out in the wrong spot... you don't need to copy it!

Links

• ATB - a bootloader for AVR Tiny microcontrollers

Changes

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