Do the E5’s VCC and VCCIO Inputs Require Separate Power Supplies?

The E5 data sheet shows two sets of power pins, one called VCC and the other called VCCIO. VCCIO is the power supply input for the PIO pins.

The later versions of the E5 Development Board, revision ‘H’ and later, had three separate voltage regulators. One was for +5V to the breadboard area; one was for +3.3V to VCC, and a separate +3.3V regulator for VCCIO. This is also shown in the schematics for the E5 Development Board.

Both VCC and VCCIO can be powered from a single +3.3V regulator.

The separate VCC and VCCIO regulators were so that the E5 Development Board printed circuit board might also support the A7 CSoC device. However, a separate A7 board was made instead.