May 27, 2018

Orange Pi PC 2 (H5) - the IO connector

Here you go. There is one error in the following diagram. Pin 13 (Uart2_Tx) is PA0, not PA2. This is what the schematic shows and would correspond to the pins on the H3 boards

This pinout is identical to the various H3 based boards sold by OrangePi (such as the Orange Pi PC and PC plus). This certainly makes sense.

What follows are my notes (from 2018) on those H3 based boards. These notes also discuss the general correspondence with the 40 pin connector used on some vintage or Raspberry Pi boards.

My notes on the H3 boards

The Orange Pi boards have a 40 pin IO connector. The diagram below shows a typical H3 board and will help to identify pin 1 on the connector.

The pins are not 5 volt tolerant, you must interface to 3.3 volt logic (3.6 volt max is the rating).

The following diagram shows the pinout for the 40 pin connector. I count 28 GPIO pins if special functions are not selected. Table 3-2 on pages 74 to 77 of the H3 datasheet show the pin multiplexor business. It seems to go like this: 

0 - GPIO input (the default)
1 - GPIO output
2 - special function as shown below
3 - alternate special function
6 - external interrupt
7 - disable

If you get tired of counting pin numbers on the above nice diagram, the following will help avoid silly mistakes:

Amazingly, the data sheet states (or seems to) that IO pins can source or sink up to 40 mA. See page 607 of the datasheet, table 9-1.

Orange Pi versus Raspberry Pi

I have not looked at this in detail, nor have I made any attempt to use expansion boards designed for the Rpi on the Opi. Power and ground are in the same location, which is promising. It at least means that things won't catch fire immediately.

It won't be immediately disastrous or hopeless. I won't say more. There would certainly be significant driver issues. Procede with caution and dig deep before trying anything along these lines.

The following diagram is for the IO connector on a "Orange Pi 2 (mini)" taken from the above article.

The following diagram is for the 40 pin connector on a Raspberry Pi. Note that older Raspi's used a 26 pin connector.

Have any comments? Questions? Drop me a line!

Tom's electronics pages / tom@mmto.org