10 Ways to Ruin Your Mini-Max microcontroller (and lose $69)

Schematic Examples of some common mistakes

Problem: No current limiting resistor for LED I/O pins are logic level control signals only

Problem: I/O pins must be limited to 5 volts Always test voltage levels

Problem: Output pin is driven high by program but low by switch Set up inputs & outputs before connecting them

Problem: Battery is connected backwards! Be very careful with this

Problem: Two outputs connected together Watch your pin direction control registers (TRIS)

Problem: Input voltage exceeded Power supply must be between +6 and +15 volts

Problem: Vdd is +5 volts from internal voltage regulator Do not apply any other voltage to this pin

Problem: Vdd pin cannot power other circuits (except low power loads like sensors, etc.)

Problem: Too much current from one I/O port Use lower current or other ports

Problem: Pins are sensitive to static electricity Avoid touching pins

“Logical” Nomenclature What do you call the pin state? OFF FALSE ZERO LOW NO 0 VOLTS Vss GROUND ON TRUE NOT ZERO HIGH YES +5 VOLTS Vdd POSITIVE