1. Circuit

The circuit should be more or less self explanatory. It provides the crystal oscillator components, the pull-up resistor on the reset line, the ISP programming header, the power input, and two 10-pin headers giving access to the port/pin lines.

I used a 10MHz crystal to match the speed of the devices that I have, but using a crystal socket would allow for easy use of other clock frequencies.

2. Construction

The prototype was made on a piece of matrix board with a piece of white paper glued to the upper surface, the pin numbers etc were marked with a sharp pencil.

The ISP header, visible at top right, is just two rows of five header-pins in parallel and makes connecting the programmer a little fiddly – I’ll use a proper 10-pin IDC socket next time.

A protection diode between the power input pins would probably be a good idea to avoid damage to the 2313 if power is connected the wrong way around, but so far I haven’t need this!

Access to the pins is a little cramped, but I had laid out the board with the intention of also including a MAX232 TTL-serial circuit to aid with debugging, and had placed everything close together to leave room. I ended up using a pre-built module instead. Next time, I’ll center the chip and leave a little more space around the pin-headers.

The point to point wiring was done with wire-wrap wire and was quite laborious. I would recommend the use of strip-board instead of matrix-board as it would avoid all the fiddly little wires between the 2313 and the headers and save a considerable amount of time.

3. Conclusion

I have found this to be a very handly little board and use it in all my work with ATtiny2313s, but am often frustrated by the fixed crystal frequency and the difficulty in inserting and removing the chip, but this is nothing that a crystal holder and a ZIF socket wouldn’t solve.

I’ll build the improved version some day…