ESP32 Serial Port

[miathedev]

Hi fellow Gophers!

I did try to write a simple hello-world application using espressifs ESP32 Plattform

package main

import (
	"time"
)

//Flash with tinygo flash -target esp32-mini32 -scheduler tasks -gc conservative -size full main.go
func main() {
	for {
		println("Hello World!")
		time.Sleep(time.Millisecond * 500)
	}
}

I flashed the project file using:
tinygo flash -target esp32 -scheduler tasks -gc conservative -size full main.go

Somehow, ill receive only odd data over serial with 115200 baud, data 8, parity none

Am i missing something that i should configure?
(The default blinking led example works fine, uart does not somehow. Using the Serial port with Arduino or EspressifsSDK works)

└─tinygo info                                                                                            1 ⨯
LLVM triple:       x86_64-unknown-linux
GOOS:              linux
GOARCH:            amd64
GOARM:             6
build tags:        linux amd64 tinygo math_big_pure_go gc.conservative scheduler.tasks serial.none
garbage collector: conservative
scheduler:         tasks
cached GOROOT:     ............

└─$ tinygo version
tinygo version 0.22.0 linux/amd64 (using go version go1.17.6 and LLVM version 13.0.0)

└─$ tinygo env    
GOOS="linux"
GOARCH="amd64"
GOROOT="/usr/local/go"
GOPATH="/home/mime/go"
GOCACHE="/home/mime/.cache/tinygo"
CGO_ENABLED="1"
TINYGOROOT="/usr/local/lib/tinygo"

└─$ xtenxtensa-esp32-elf-gcc -v
Using built-in specs.
COLLECT_GCC=xtensa-esp32-elf-gcc
COLLECT_LTO_WRAPPER=/home/MYUSER/esp/xtensa-esp32-elf/bin/../libexec/gcc/xtensa-esp32-elf/5.2.0/lto-wrapper
Target: xtensa-esp32-elf
Configured with: /builds/idf/crosstool-NG/.build/src/gcc-5.2.0/configure --build=x86_64-build_pc-linux-gnu --host=x86_64-build_pc-linux-gnu --target=xtensa-esp32-elf --prefix=/builds/idf/crosstool-NG/builds/xtensa-esp32-elf --with-local-prefix=/builds/idf/crosstool-NG/builds/xtensa-esp32-elf/xtensa-esp32-elf/sysroot --with-sysroot=/builds/idf/crosstool-NG/builds/xtensa-esp32-elf/xtensa-esp32-elf/sysroot --with-newlib --enable-threads=no --disable-shared --with-pkgversion='crosstool-NG crosstool-ng-1.22.0-80-g6c4433a' --disable-__cxa_atexit --enable-cxx-flags='-fno-rtti -ffunction-sections' --with-gmp=/builds/idf/crosstool-NG/.build/xtensa-esp32-elf/buildtools --with-mpfr=/builds/idf/crosstool-NG/.build/xtensa-esp32-elf/buildtools --with-mpc=/builds/idf/crosstool-NG/.build/xtensa-esp32-elf/buildtools --with-isl=/builds/idf/crosstool-NG/.build/xtensa-esp32-elf/buildtools --with-cloog=/builds/idf/crosstool-NG/.build/xtensa-esp32-elf/buildtools --with-libelf=/builds/idf/crosstool-NG/.build/xtensa-esp32-elf/buildtools --enable-lto --enable-target-optspace --without-long-double-128 --disable-libgomp --disable-libmudflap --disable-libssp --disable-libquadmath --disable-libquadmath-support --disable-nls --enable-languages=c,c++ --disable-libstdcxx-verbose --enable-threads=posix --enable-gcov-custom-rtio
Thread model: posix
gcc version 5.2.0 (crosstool-NG crosstool-ng-1.22.0-80-g6c4433a) 

[aykevl]

Huh, that's odd. I can't see anything wrong with your code or the configuration.
Do you get this garbled text every half second?

[miathedev]

Yes. That works.

[aykevl]

Ok, so at least the program is running on the ESP32.
One thing you could perhaps try is to look at the length of the string that should have been printed (14 bytes, including CRLF newline) and the line that is actually printed. If the baud rate configured in the serial monitor is too low, it will print more. If the baud rate is too high, it will print less.
... if that works, it means there is a weird baud rate mismatch somewhere. Which still seems unlikely to me.

[aykevl]

I tested the code locally and it works for me (using an esp-wroom-32).

[miathedev]

For testing purposes i installed everything new in a VM using:

• go1.17.9
• xtensa-esp32-elf-linux64-1.22.0-80-g6c4433a-5.2.0
• esptool.py via pip install esptool
• ubuntu 20.04.4 LTS

My ESP32 is still sending odd data.

Can you please send me what you use as environment? Maybe this will solve my problem and we could compare.

[aykevl]

I'm using:

• Go version 1.17.8
• xtensa-esp32-elf-ld --version: GNU ld (crosstool-NG esp-2021r2) 2.35.1.20201223
• esptool.py via pip3 install esptool
• Debian 11 (bullseye)

And I'm using picocom --baud 115200 /dev/ttyUSB0 to read the serial monitor.

You could try:

• Erase the flash using esptool.py --chip=esp32 erase_flash
• Download my examples/serial binary here: test.zip (unfortunately GitHub requires it to be zipped)
• Flash it using esptool.py --chip=esp32 --port /dev/ttyUSB0 write_flash 0x1000 test.bin -ff 80m -fm dout

This would help to figure out where the problem lies (in the serial monitor or in the binary that you produce).

[miathedev]

What i did so far:

• Erase flash, reflash project (didnt help)
• Erase flash, flash your binary (didnt help)
• use picocom for both examples (didnt help)

Im always getting odd data.

Im using esptool.py v3.3

esptool.py --chip=esp32 --port /dev/ttyUSB0 write_flash 0x1000 test.bin -ff 80m -fm dout
esptool.py v3.3
Serial port /dev/ttyUSB0
Connecting.....
Chip is ESP32-D0WDQ6 (revision 1)
Features: WiFi, BT, Dual Core, Coding Scheme None
Crystal is 26MHz
MAC: 30:ae:a4:5d:cd:80
Uploading stub...
Running stub...
Stub running...
Configuring flash size...
Flash will be erased from 0x00001000 to 0x00001fff...
Flash params set to 0x031f
Compressed 3152 bytes to 2395...
Wrote 3152 bytes (2395 compressed) at 0x00001000 in 0.3 seconds (effective 93.4 kbit/s)...
Hash of data verified.

Leaving...
Hard resetting via RTS pin...

which esptool version do you use?