I had an issue with readings from the serial monitor with my Windows/Atom/PlatformIO serial monitor and emonTH with the programmer from openenergymonitor shop.
The solution? set the baud on 115200 (not on 9600 as I have read it somewhere)
What you saw there is absolutely typical of what you see with a wrong (too slow) baud rate. On the other hand, if your baud rate is set too fast, you can see nothing.
So if you are using a serial connection, and you don’t see what you expect, it is worth trying the range of baud rates before you look further.
If code compiles successfully upload the firmware by clicking on Upload (3)
Note: A USB to UART cable is required to upload to emonTx / emonTH
After successful upload check nodeID has changed by viewing serial output, click Serial Monitor (4) and choose 9600 baud.
Also at the command line it says:
4. View serial port with PlatformIO CLI
$ pio serialports monitor -b9600
It would help if that bit (baud) of the manual is adjusted. This really had put me on the ‘wrong’ track so to speak and made it really frustrating, because I started to think I was missing something. Not sure if you can specify an exact baud rate, but at least something that says this can be changed if you see ‘gibberish’…