USB AVR chips

USB AVR chips

Here are memos on AVRs with focus on newer hardware USB chips.

USB enabled AVR chips and board:

• ATmega8u2 Flash 8KiB
  • Board: Arduino UNO R2 serial
• ATmega16u2 Flash 16KiB
  • Board: Arduino UNO R3 serial
• ATmega32u4 Flash 32KiB
  • Board: Teensy1.0, Teensy2.0, Arduino Leonardo, pro micro, Arduino micro, many badusb usb virtual keyboard (16MHz)
• AT90USB1286 Flash 128KiB
  • Board: Teensy2.0++ (16MHz)
• AT90USB1287 Flash 128KiB -- USB OTG support
  • Board: AT90USBKEY2 (8MHz)

Programming USB enabled AVR chips

Hardware USB enabled AVR chips can be programmed in 3 ways:

• ISP (In System Programmer) on ICSP port
  • Host application on PC: avrdude
  • Protocol: AVR910
    • This is the same protocol to program a non-USB enabled AVR chips ATmega328 on Arduino Uno R3 board via SPI connection via ICSP port.
  • Connection: SPI (Serial Peripheral Interface) connection! (MOSI/MISO/... ) on ICSP port
  • Programming hardware (ISP programmer):
    • AVRISP mkII (-c avrisp2)
    • FT232 based ISP (My toy) https://github.com/osamuaoki/avrdude-friend (-c ttl232r)
    • Arduino based ISP (old AVR-ISP-like)
      • https://www.arduino.cc/en/Tutorial/ArduinoISP running ISP sketch https://github.com/rsbohn/arduinoisp (-c avrisp)
      • Hardware (ISP): ARDUINO UNO based http://mightyohm.com/blog/2008/09/arduino-based-avr-high-voltage-programmer/
  • Bootloader code on MCU: None
• CDC Class USB AVR Bootloader (Communications Device Class)
  • Host application on PC: avrdude -c AVR109
  • Protocol: AVR109
    • This is the same protocol to program a non-USB enabled AVR chips ATmega328 on Arduino Uno R3 board via serial UART connection via on USB-serial board FT232 (as on STK500). Some Arduono needs external USB-serial board.
  • Connection: USB
  • Programming hardware: None (USB cable)
  • Bootloader code on AVR:
    • 4KiB: LUFA CDC (http://www.fourwalledcubicle.com/LUFA.php)
    • 4KiB: Caterina (Arduino Leonardo comes with this bootloader, smaller optimized)
      • https://github.com/arduino/Arduino/tree/master/hardware/arduino/avr/bootloaders/caterina
      • https://github.com/adafruit/Caterina-Bootloader
• DFU Class USB AVR Bootloader (Device Firmware Update)
  • Host application on PC: FLIP (Windows), dfu-programmer (Linux) (newer avrdude also seems to support this)
  • Protocol: AVR282: USB Firmware Upgrade for AT90USB
    • This is the same protocol to re-program a fresh ATmega16u4 which normally function as USB to TTL-UART converter on Arduino Uno R3 board from USB port.
  • Connection: USB
  • Programming hardware: None (USB cable)
  • Bootloader code on AVR:
    • 4KiB: Atmel DFU? (Bare chip comes with this) (closed source)
    • 4KiB?: LUFA DFU (http://www.fourwalledcubicle.com/LUFA.php)
    • 4KiB: Leonardo DFU (Arduino+LUFA)
    • USB DFU Bootloader Datasheet
• HID Class USB AVR Bootloader (Human Interface Device)
  • Host application on PC:
    • hid_bootloader_cli (LUFA)
    • teensy_loader_cli modified https://github.com/osamuaoki/teensy_loader_cli
    • teensy_loader_cli https://github.com/PaulStoffregen/teensy_loader_cli (Only for Teensy)
  • Connection: USB
  • Programming hardware: None (USB cable)
  • Protocol: Teensy Programming Protocol Specification (pjrc)
  • Bootloader code on AVR:
    • 4KiB?: LUFA HID (http://www.fourwalledcubicle.com/LUFA.php)
    • 512B: Teensy (striped down firmware, proprietary)
    • 512B: nanoBoot (teensy compatible GPL3 firmware, https://github.com/volium/nanoBoot )
• Mass Storage Class USB AVR Bootloader
• Printer Class USB AVR Bootloader
• High voltage programming -- last resort for bricked EEPROM chips
  • Host program: avrdude http://www.atmel.com/webdoc/stk500/stk500.highVoltageProgramming.html

On Windows system, you need to install device driver file for all but HID Class USB AVR Bootloader.

FYI: ATmega328p on Arduino Uno R3 comes with optimized 512B optiboot serial line bootloader whitch uses the same protocol as CDC Class USB AVR Bootloader.

FYI: "Let’s shorten the bootloader time of the Leonardo/Micro/Esplora": http://www.leonardomiliani.com/en/2013/accorciamo-i-tempi-del-bootloader-della-leonardomicroesplora/

LUFA

LUFA is a free AVR USB stack library and bootloader program licensed under the MIT license.

• The latest LUFA release: http://www.fourwalledcubicle.com/LUFA.php
  • GIT: https://github.com/abcminiuser/lufa
  • LUFA Library Documentation (170418)
• Tutorial: http://fourwalledcubicle.com/AVRArticles.php
  • GIT: https://github.com/abcminiuser/avr-tutorials

LUFA seems to be preferred library over:

• Atmel USB AVR Stack (Atmel Inc.)
• PJRC Teensy Stack (Paul Stoffregen)
• V-USB (Objective Development) -- USB on serual AVR

hid_bootloader_cli

hid_bootloader_cli in LUFA is modified Teensy CLI. This should be good drop in replacement (except for ARM based teensy 3 support etc.)

I have made updated bootloader cli based on the newer teensy_loader_cli to support LUFA HID bootloader with hid_bootloader_cli as https://github.com/osamuaoki/teensy_loader_cli

EEPROM (Fuse)

Fuse calculator:

• http://www.engbedded.com/fusecalc/

See more on AVR fuses