Designing Embedded Hardware, 2nd Edition

Building It

Once the PCB has been fabricated and checked carefully to ensure that all pads and tracks are intact and properly etched, do the construction one step at a time and check everything as you go. Using a multimeter , do a continuity test between the ground pads and the ground pin on the power connector.

Powering Up for the First Time

Start construction by soldering in the power connector, voltage regulator, and its support components, including the "power" LED if you've included one in your design.

Once you've soldered in the components needed for the power supply, power up the board and check that it is operational. Also check that you have power on every pad on the board where you expect power to be, and check the ground pads to make sure there is no power where you expect no power to be.

Next, solder in the power-decoupling capacitors for the ICs. Add the processor's oscillator and decoupling capacitors. If the oscillator is a module, check its operation with an oscilloscope. Does it have the right waveform on its output pin?

If IC sockets are used, solder these next and then insert the components. If you're using a processor that needs to be externally reprogrammed, then a socket is a good idea.

Add in the Processor

Make sure once again that the system is powered down. Using a multimeter's continuity test function, check that the processor footprint has the appropriate power and ground connections to the right pins. Solder the processor to the board (or plug it into a socket ...