Cima attiny85

A basic program for attiny 85 to demonstrate Aurduino-less development for this tiny board with processor.

About ATTINY85

SoC Atmel 1705 TINY85 20SU is:

• AVR based 8-bit microprocessor
• 8KB of flash memory
• 512 B SRAM
• 6 GPIO (HW PWM, AD converter)
• Complete TINY85 datasheet

Digispark Breakout board is:

• Opensource PCB layout
• With micro USB
• 5V stabilization
• 6 Breakout GPIO pins
• 3 power in/out pins
• TINY85's flash is preloaded with bootloader Micronucleus that makes it possible to laod main program via USB

Development

Prereqisities

1. USB drivers: Digistump.Drivers.zip

NOTE: Find the latest release at https://github.com/digistump/DigistumpArduino/releases/

• Unzip anywhere
• Install using Install Drivers.exe
• Plug in your ATTINNY 85 board
• 

Troubleshooting: Digispark ATtiny85 Download and install

2. GCC-AVR toolchain alternatives

1. GCC-AVR toolchain opensource 11.1.0 x64 win

   • NOTE: find the most up to date compilers at https://blog.zakkemble.net/avr-gcc-builds/

   • unzip to dedicated folder somwhere where you store your compilers
   • You will need to reference this folder multiple times in your project

2. GCC-AVR toolchain from microchip (registration needed)

   • NOTE: find the most up to date compilers at https://www.microchip.com/en-us/tools-resources/develop/microchip-studio/gcc-compilers

3. AVR DUDE

• A tool for uploading and downloading compiled binary to TINY85 microchip

NOTE: ISP = in-system programming; a technique to upload your code

TODO Do I really need it since micronucleus provides executable to handle the upload?

4. Micronucleus

an USB emaulating bootloader that has a counterpart on PC operating system allowing you to upload your program.

A good article for understanding the nucleus & Tiny85 flash life cycle

• Download micronucleus-cli-master-882e7b4a-x86_64-MINGW64_NT-10.0-17763.zip

• NOTE: latest releases

• unzip it like you did with AVR-GCC somwhere comfortable for you to reference it within Your project

5. CMAKE

https://github.com/adigie/stm32-cmake-template/blob/example_l053/CMakeLists.txt

In root of this project execute to materialize cmake project ad have it ready for build

cmake -G Ninja -B ./build/

Ninja

https://github.com/ninja-build/ninja/releases

Ninja is a replacement of Makefile.

In order to compile this project simply go to folder build and write ninja

cd build
ninja

5. BOOST

Linking

Arduino Files - including linker script needed fro our chip/board

Upload the code

micronucleus --run build\src\CimaAttiny85.hex

Upgrading micronucleus

Pretty nice article (https://www.iot-experiments.com/micronucleus-bootloader-upgrade/) gives a good description of how to upgrade your Digispark to the latest version.

1. Download latest HEX representation of the micronucleus firmware e.g. upgrade-t85_default.hex

2. Unplug device

3. Run

micronucleus.exe --run upgrade-t85_default.hex

4. Plug in your device

5. Upgrade tkaes a moment

   NOTE: USB in windows will constntly detect plug-in and plug-off, this can be eliminated

   1. Unplugging the device
   2. micronucleus.exe --erase-only
   3. plug in the device

6. Done!

More on upgrading

• https://gist.github.com/Ircama/22707e938e9c8f169d9fe187797a2a2c
• https://blog.podkalicki.com/how-to-compile-and-burn-the-code-to-avr-chip-on-linuxmacosxwindows/

Additional reading

• https://blog.laskarduino.cz/zaciname-s-attiny85-digispark/
• ATtiny85: Introduction to Pin Change and Timer Interrupts -- tutorial to input pins and timer interrupts with extensive documentation
• ATtiny85: Blinking Without Clock Cycles -- utilization of timer built in operations (toggle port)
• Digispark wiring diagram