Microcontrollers come in all sorts and sizes, and it’s very tempting to use them every-where, even for very simple tasks. Tiny, inex-pensive microcontrollers especially suited to very simple tasks, such as the Microchip PIC10F2xx family, are also available. Thanks to their compact size and their ability to source or sink 25 mA on their I/O pins, these miniature microcontrollers are a good choice for driving LEDs directly in miniature lighting effect devices. They can also operate from a 2-V supply voltage, which allows them to be powered directly by batteries (such a button cells).
However, their small dimensions have a few drawbacks, especially for developing prototypes. The first drawback is that the IC leads are so small that soldering is not easy, and the lead pitch makes them difficult to use with a breadboard or perforated proto-typing board. Another problem is that they can only be programmed in-system, which means that you always need an extra header for programming (even if you can find a suit-able ZIF socket for a programmer, it will cost you an arm and a leg). The small PCB described here is intended to make it easier to use Microchip PIC10F2xx devices in the SOT23-6 package without making the entire arrangement so big that you could just as well use a DIL version of the same IC.
Although the easiest way to solder the six-lead IC to the board is to use solder paste and a hot-air iron, it is in fact possible to do this with a normal soldering iron. Any excess sol-der can be removed with desoldering braid. All leads are brought out to SIL connector K1, which has a more conventional 100-mil pitch and mates perfectly with a breadboard or piece of perfboard for prototype develop-ment. What’s more, it is a one-to-one match to the connector of a Microchip PICkit2 or PICkit3 programmer.
The pads for the IC pins are surrounded by larger pads that can be used as attachment points for wires, resistors, LEDs and so on. Once the prototype and the firmware are finalised, the portion of the board outside these pads can be sawn off and/or filed down to make it easier to fit the board in a minia-ture enclosure.
Author :Luc Lemmens - Copyright : Elektor
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