AT Tiny Exploration Project

Messing with drivers and peripherals of the attiny85

• Required Software

  • Arduino IDE
  • AVR GCC Compiler and Debugger
  • dw-link

• Required Hardware

  • ATtiny85 Development Board
  • Arduino Uno
  • USB-A to USB-B cable
  • MCU jumper wires

TODO list

• Create own linker script for this MCU
  • https://gcc.gnu.org/wiki/avr-gcc
• Create own initialization function for this MCU
• Create own BSP for this MCU based on datasheet (no Arduino / AVR helper functions!)

Build

To get the toolchain to work on this repo, you need to install the Arduino IDE and add the following to your path:

• C:\Program Files (x86)\Arduino\hardware\tools\avr\bin
• C:\Program Files (x86)\Arduino\hardware\tools\avr\etc OS equivalent also applies

> cmake -DCMAKE_BUILD_TYPE:STRING=Debug -Bbuild -G Ninja
> cd build
> ninja

Load / Debug

Download the AVR 8 bit toolchain for windows (or your OS). Extract the zip somewhere and add the following to your PATH variable (path here may differ depending on where you download it.)

• C:\dev\avr8-gnu-toolchain-win32_x86_64\bin

This gives you access to the avr-gdb executable , which is no longer packaged with the Arduino IDE install.

Next, in your clone of dw-link, you will want to upload the file dwlink/dwlink.ino to your Arduino Uno using the IDE.

Next, make the following connections from the Arduino Uno to your ATTiny85 dev board using the jumper wires:

Signal	Arduino Pin	ATtiny85 Pin
Ground	GND	GND
SDK	D13	P2
MISO	D12	P1
MOSI	D11	P0
VCC	D9	VIN
Reset	D8	P5

Now, when plugging in your Arduino, it should show up as a COM port on your device manager, and you should connect to it like so from the command line:

> avr-gdb -b 115200 build/main.elf
(gdb) target remote COM[X]
(gdb) load
(gdb) break main
(gdb) c

NOTE: Make sure that the "X" above is a COM number below 10, avr-gdb has had issues finding the COM number when it is above 10.

• dw-link Reference
• avr-gdb Reference

Old Notes

Traditional Bootloader Method

• Drivers for dev board
  • https://github.com/digistump/DigistumpArduino/releases
  • Digistump.drivers
  • Dpinst64.exe
  • Shows up as “microchip tools” -> digispark bootloader!
  • In Arduino, download digispark boards
    • http://digistump.com/wiki/digispark/tutorials/connecting
    • https://www.youtube.com/watch?v=MmDBvgrYGZs

AVR Dude and ATTiny ISP Programmer

https://learn.sparkfun.com/tutorials/tiny-avr-programmer-hookup-guide/all https://learn.sparkfun.com/tutorials/pocket-avr-programmer-hookup-guide#using-avrdude-via-command-line https://shallowsky.com/blog/hardware/attiny85-c.html

Connect to the tiny board with the command

> avrdude -c usbtiny -p attiny85

Loading and flashing with ATtiny ISP programmer: https://electronut.in/getting-started-with-attiny85-avr-programming/