microcontroller

RIOT-OS

• an OS for IoT
• runs on ARM, ESP32, ESP8266, ...
• https://github.com/RIOT-OS/RIOT

setup VirtualBox Image for RIOT development

• https://github.com/RIOT-OS/RIOT/wiki/Howto%3A-Create-a-VirtualBox-Image-for-RIOT-development

AVR: ATtiny85

tools

• dmesg: list kernel ring buffer
• lsusb: list usb devices
• avrdude: for programmer, transfer code from computer to microcontroller
• gcc-avr: compiler for AVR
• avr-libc: AVR C library
• optional tools
  • binutils-avr: tools like assembler, linker
  • gdb-avr: debugger for

example: main.c

• Step 1: we need to bring our program to uC (microcontroller)
• Step 2: run the uC

Step 1: compile, build and flash

In order to bring our program to the uC we need a elf format. To be short. These are the steps for it:

avr-gcc -mmcu=attiny85 -Os -c main.c  -o main.o
avr-gcc main.o -o main.elf
avr-objcopy -O ihex -j .text -j .data main.elf main.hex
avr-size --mcu=attiny85 -C main.elf 
avrdude -p attiny85 -c usbasp -U flash:w:main.hex:a

The connection between the computer and microcontroller is done with a programmer. In my case its a USBasp. For more: https://fischl.de/.

Usually the USBasp will have a ISP 10 pin cable witch is wired to the relevant pins in ATtiny85.

AVRISP mkII is also a good choice. It's just hard to find a original one and its expensive. You also have to extra power you uC.

Step 1: running After flashing process the program is loaded into the ATtiny85. Wire a circuit with a led to PIN 5 on ATtiny85 and power it up.

circuit

• the led will glow every 500ms with flashed main.c example

cheatsheet

• list supported uController: avrdude -p?
• check connection between programmer (e.g. USBasp, AVRISP, ...): avrdude -p attiny85 -c usbasp or avrdude -p t85 -c usbasp

electricity

• power-bus in breadboard (+ and - lines)
• red cable is +
• black cable is -
• integrated circuit (IC) = chips comes with DIP (dual in-line package) for the middle gab in breadboard

Atmel ATTiny85

Reset	1	8	VCC (5V)
		2	7	SCK
		3	6	MISO
GND		4	5	MOSI

Serial Peripheral Interface

• SCK: Serial Clock
• MOSI: Master Output Slave Input
• MISO: Master Input Slace Output

USB to TTL Serialadapter

• check connection with dmesg
• connect with minicom
• convert TTL logic to RS232
• USB serial converter

ISP AVR

• 10 or 6 pins
• In System Programming
• use with: avrdude -p attiny85 -c avrispmkII

ESP32 (M5Stack)

• ESP32 is implemented in M5Stack
• Espressif ESP32 is the successor of Espressif ESP8266
• example based on linux (ubuntu)

PlatformIO

• install PlatformIO as extension in vscode or atom

create new project

• Board: M5Stack Core ESP32
• Framework: Arduino

run (ide)

• build 'PlatformIO: Build'
• upload 'PlatformIO: Upload'

run (command line)

pio run

throubleshooting

Issue

[Errno 13] Permission denied: '/dev/ttyUSB0'

Solution

sudo chmod 666 /dev/ttyUSB0