microcontroller board

[a.soliman]

Hello all,
I want to ask about the proper hardware design for a microcontroller board...  tips and tricks for the power rails, input and output protection and anything that I should be aware of to ensure the operation stability

Thanks in advance

[Ian.M]

That is incredibly dependent on the microcontroller family chosen. Many have special requirements.

However there are a few common factors:

* Ground plane - don't try to do without it if there are external signals with less than 1us between edges.  You may be able to get it to work with faster signals without one but its not good practice.

* Connect *ALL* supply and ground pins unless the datasheet says otherwise - internal power bus metalisation between different sections of the chip is often not sized to carry the full rated supply current.

* Decouple *ALL* Vdd supply pins as close to the pin as possible.

* Keep supply tracks short and wide - don't snake one round the board edge to avoid a wire link or a few vias.

* Keep any external crystal connections close to the chip and clear of other signals.

For the rest, if there is a manufacturer's demo board or reference design, STUDY IT, otherwise study the datasheet till you can quote it in your sleep!
 

[poorchava]

Unless your uC has internal slew rate limiting,  you may want to connect a small resistor (47-100R would be a good start)  in series with every output pin.  This will decrease the amount of ringing and also protect the uC a little bit in case of short circuit.

Make sure that traces from crystal to the uC are as short as possible,  preferably far from other signal traces.

Make sure to include at least one larger cap somewhere nearby the uC for bulk filtering.

Make sure that the reset pin is treated exactly as outlined in the datasheet. Use weak pull-up in case the uC doesn't have one internally (100k would be good start)

[a.soliman]

Thank you guys