Connecting to the Odroid HC4 via UART
=====================================
date: 2021-12-30

In the process of trying to flash OpenBSD on my Odroid HC4 (still
not achieved.. but the FAQ says the chip is supported...), I
needed to connect via the serial console.

The board has a UART Console with the following pins:


       _____UART____
       |Pin 4 - GND|
       |Pin 3 - RXD|
       |Pin 2 - TXD|
       |Pin 1 - VCC|
       \___________|

       CON5
       3.3V LVTTL

-> Source: https://wiki.odroid.com/odroid-hc4/hardware/hardware


And I have a USB to Serial with the following wires (your colors
may vary!):

       --red----[VCC]
       --green--[RXD]
       --white--[TXD]
       --black--[GND]

To the best of my research, these stand for:

- VCC: power
- RXD: receive
- TXD: transmit
- GND: ground

I had success connecting _without the power_, hooking up only
GND, RXD, and TXD.

The connectors on my serial are a bit too large, too, so I had to
turn them diagonal so the squares would fit in the notches, but
it worked!

On OpenBSD (host OS), I was able to connect like so:

       $ doas cu -l cuaU1 -s 115200

(cuaU1 is the serial USB device--not 0 on my machine since my
motherboard has its own serial out that takes up cuaU0).