tinygo_experiments

TinyGo Experiments

Some experiment codes written in TinyGo, the Go compilier for small places (like microcontrollers).

package main

import (
	"machine"
	"time"
)

func main() {

	led := machine.LED
	led.Configure(machine.PinConfig{Mode: machine.PinOutput})

	for {
		led.Set(!led.Get())
		time.Sleep(time.Millisecond * 500)
	}

}

Setup TinyGo

Install Golang

For Windows, simply download go<version>.windows-amd64.msi and run.

For Linux, find the correct target and

wget https://go.dev/dl/go{version}.linux-{architecture}.tar.gz
sudo rm -rf /usr/local/go && sudo tar -C /usr/local -xzf go{version}.linux-{architecture}.tar.gz

Single-board computers with ARMv8 is arm64 and ARMv7/v6 is arm6vl.

Install TinyGo

For Windows, simply download tinygo<version>.windows-amd64.zip and unzip.

For Linux, find the correct target and

wget https://github.com/tinygo-org/tinygo/releases/download/v{version}/tinygo_{version}_{architecture}.deb
sudo dpkg -i tinygo_{version}_{architecture}.deb

Setup $PATH

For the first time installing TinyGo, Windoes users have to add <path>\TinyGo\bin to $PATH.

For Linux:

sudo nano ~/.bashrc

Add the following two lines at the end

export PATH=$PATH:/usr/local/go/bin
export PATH=$PATH:/usr/local/tinygo/bin

Press Ctrl + X then Y then enter to save, reopen the terminal or apply the changes with

source ~/.bashrc

Check $PATH:

go version
tinygo version

Install AVR Tools (Optional)

8-bit AVR boards require additional compiling and flashing tools.

For Windows users, download and unzip AVR-GCC then add <path>\avr-gcc-<version>-x64-windows\bin to $PATH, then reopen the terminal.

For Linux, run

sudo apt-get install gcc-avr avr-libc avrdude

Install TinyGo Packages (Optional)

go get -u tinygo.org/x/drivers
go get -u tinygo.org/x/tinydraw
go get -u tinygo.org/x/tinyfont
go get -u tinygo.org/x/bluetooth

Run TinyGo Script

Setup Project

1. Create a directory. It is recommended to open it in VS Code with the TinyGo extension installed.
2. Create main.go.
3. Initialize the Go project with

go mod init <project name>

Compile and Flash Script

If external drivers are used, update go.mod with

go mod tidy

To compile and flash the script, run

tinygo flash -target <target> -port <port> main.go
# or
tinygo flash -target=<target> -port=<port> main.go

Find the target name in official website (does not list all the targets) or official repo.

To look up the port, run mode on Windows (like COM{x}) or dmesg | grep tty on Linux (like /dev/tty{something}).

For devices using UF2 firmware, make sure the device has entered bootloader mode before flashing. In bootloader mode the device would be on a different port as well.

For most SAMD21/51 and nRF boards with Adafruit UF2 firmwares, pressing the reset button twice. For Raspberry Pi Pico you'll need to hold down the BOOTSEL button and re-connect USB. The micro:bits has a separate chip as USB interface so it can be flashed directly. Both RPi Pico and micro:bits do not need to specify ports when flashing.

For Arduino Nano 33 IoT, you can install the Adafruit UF2 bootloader with this Arduino script. (After that you can upgrade the boodloader with .uf2 files.)

For DigiSpark (ATTiny85), install the bootloader (On Windoes use Zadig) and download micronucleus. Add it to your $PATH. TinyGo will ask you to re-connect DigiSpark before flashing (no port needed).

For Bluepills, get a ST-LINK/V2 programmer and download/unzip OpenOCD, add the <path>\openocd-0.10.0\bin to $PATH. Port is not needed but you may have to hold down reset button before flashing and release as soon as OpenOCD's first message appears...

Notes on Pins and I2C Bus

See the machine package definitions and board pinouts for the correct pin number and I2C/SPI bus. For some targets I2C. SPI and/or PWM may not be supported yet.

micro:bit V2

For both V1 and V2, the onboard LSM303AGR is connected to the internal I2C bus (I2C0). However for external I2C devices, V1 uses the same bus while V2 uses I2C1:

machine.I2C1.Configure(machine.I2CConfig{
	SCL:       machine.SCL1_PIN, // P19
	SDA:       machine.SDA1_PIN, // P20
	Frequency: machine.TWI_FREQ_400KHZ,
})

V2 also has the following additional pins:

• a buzzer at BUZZER
• a capacitive touch (on the logo) at CAP_TOUCH``; do not need to be pulled up and pin.Get()returnsfalse``` when touched)
• a mic at MIC and its enable pin/indicator LED at MIC_LED. See this script for demostration.
• the LED pin is just a dummy

Bluepills

The built-in LED may be at PC13 or PB12.

Arduino Nano 33 BLE Sense

The board's onboard I2C sensors are connected to the internal I2C1 bus which has to be powered up with P0_22 and pulled up with P1_00, although the TinyGo driver implementations already dealt with the issue.