November 3, 2026

MOD_EMUP - ARM interface

We have enough knowledge of the cable and protocol to tempt me into trying something. I laid out a PCB to use signals from an ARM board to control the EMUP. The board is mostly signal routing and level shifting.

I chose to use an Orange Pi PC as the ARM board. I have a number of these on hand and I know them well from other projects, so they will make things easy for me.

I see that Orange Pi PC are still available on AliExpress for about $60 -- so at this time, anyone who wants to duplicate what I am doing will have no problems doing so.

The boards are being fabricated as I type this. I will have more to say when I have them in hand.

Other boards

I thought of using a Zynq 7000 board with FPGA. All the gpio are 3.3 volt only. This is also true of the Allwinner H3 on my Orange Pi PC board. It is also true of the Raspberry Pi (but I don't have any of those).

If I used an STM32H743, it has lots of 5 volt tolerant inputs. They are marked "FT" on the datasheet. If I had more experience with those they would let me avoid the two level shifter chips I needed to use. On the other hand, working with a familiar board and software is a far bigger win than saving two inexpensive level translators.

Have any comments? Questions? Drop me a line!

Tom's Electronics pages / tom@mmto.org