ReadByte not working in tutorials/SerialMonitor

[William-Purvis]

I've just installed tinygo and tested the blinky and serialmonitor tutorials. The basic serialmonitor code that simply writes "hello World!" works fine, but compiling the more advanced one which accepts keystrokes over the USB port waits for input then simply
types 'p' and then hangs. I've tried putting extra prints in but nothing useful shows up.
A print before the call to ReadByte works - generates a flood of prints until I type something in, then responds with a single 'p' then hangs, no further output.

I'm talking to a waveshare-rp2040-zero.

Any ideas welcome...

[Gustavomurta]

I suggest you test the "echo" examples.
If you have any questions, feel free to ask.
Then let us know the results.

https://github.com/tinygo-org/tinygo/tree/release/src/examples/echo
https://github.com/tinygo-org/tinygo/tree/release/src/examples/echo2

[William-Purvis]

OK, tried both versions. Both behave in same manner as reported above, i.e.: type in a few characters and hit return.
It responds with a single character 'p' then goes dead.
echo2 compiled using 'go' works as I'd expected, i.e.:
$ ./echo2
Echo console enabled. Type something then press enter:
abcdefg
You typed (scanf) : abcdefg
abcdxyz
You typed (scanner) : abcdxyz
^C
Also tried compiling for an Arduino Nano, got the following for both examples:
$ tinygo build -target arduino-nano -serial usb echo2.go
/usr/local/lib/tinygo/src/machine/serial-usb.go:6:12: undefined: Serialer
/usr/local/lib/tinygo/src/machine/serial-usb.go:9:11: undefined: USBCDC

[William-Purvis]

Looking at the first program, if see you are reading the port with ReadBytes(). I have been working with on a different program using network connections to another program and initially tried, this but it reported ReadBytes not declared for net.Conn, only Read() which seems to be equivalent. However, I couldn't get that to work either, and ended up reading the connection in the manner shown in echo2.go, i.e. using bufio.NewScanner. This works, though it seems to inject a zero byte in the first string returned by scanner.Text(). Also it occurs to me that the two echo examples do not specify the line speed, a comment says whatever the default for your device. I've always used 115200 for this with C coding, but explicitly specified. Could this be part of the problem?

[William-Purvis]

Further tests - Arduino-nano complains not enough RAM (hardly a surprise).
SEEED XIAO-RP2040 behaves the same as the waveshare-RP2040-zero.
I don't have any others to try...