How To Route A PSoC Microcontroller

SIO Pins

SIO pins can:

• Act as digital I/O
• Can handle up to 5.5V on SIO pins, regardless of the microcontrollers maximum supply voltage (this is due to no top ESD diode).
• Sink/source more current than GPIO
• Can have programmable drive voltage levels

SIO pins cannot:

• Act as analogue I/O. This means you cannot connect them up things like the ADC, VDAC, IDAC, e.t.c.
• Cannot act as LCD I/O.

Some SIO pins also have fixed-hardware I2C peripherals connected to them. In my experience, SIO pins also tend to use a little more power than GPIO, it seems that their input buffers consume more current.

Information on the SIO pins from a PSoC datasheet.