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• ATSAMD21G18 microcontroller
  
  • 32-Bit ARM Cortex M0+ at 48 MHz
  • Flash Memory: 256 KB
  • SRAM: 32 KB
• Compatible with the Arduino Zero board and can be programmed using the Arduino IDE as an Arduino Zero
• A buzzer is mounted on the Cubetto PCB and connected to Arduino pin number 17 (pin "A3" on the Arduino Zero and named "PA04" in the SAMD21 documentation)
  • https://github.com/simonbates/cubetto/blob/e1a6dd2e658eb107b8e077f41daf28cacc614a1f/CubettoLibrary/CubettoLibrary.h#L24
  • https://github.com/arduino/ArduinoCore-samd/blob/142814a5d2b4793a8db5a01093cea9d2a47ac3cb/variants/arduino_zero/variant.cpp#L47
• The SAMD21 has a built-in Digital Audio Converter (DAC) attached to pin A0
  • The buzzer on the Cubetto is not attached to this pin. It is attached to a digital (2-state) output pin and Pulse Width Modulation (PWM) must be used to play audio on the mounted buzzer.
• The analog pin A0 might be available via a pad on the Cubetto PCB

Image Added

Cubetto Firmware

Primo Video Guide to Updating the Cubetto Firmware Using the Arduino IDE:

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• https://www.arduino.cc/reference/en/language/variables/utilities/progmem/
• http://www.nongnu.org/avr-libc/user-manual/group__avr__pgmspace.html

Audio Libraries and Code Samples

• Arduino PWM tone() function for SAMD
  • https://github.com/arduino/ArduinoCore-samd/blob/master/cores/arduino/Tone.cpp
• Arduino PWM tone() function for AVR
  • https://github.com/arduino/ArduinoCore-avr/blob/master/cores/arduino/Tone.cpp
• AudioZero audio library for Arduino Zero
  • https://github.com/arduino-libraries/AudioZero/blob/master/src/AudioZero.cpp
  • Play sampled audio using the built-in DAC on pin A0
• PWM audio for Arduino with Atmega168 at 16 MHz
  • https://playground.arduino.cc/Code/PCMAudio/
  SAMD21 Timer library for the Arduino Zerohttps://github.com/avandalen/avdweb_SAMDtimerfor Arduino with Atmega168 at 16 MHz
  • https://forumplayground.arduino.cc/index.php?topic=454243.0/Code/PCMAudio/

Arduino/SAMD21 Timers

• Forum thread: "Changing Arduino Zero PWM Frequency"
  • https://forum.arduino.cc/index.php?topic=346731.0
• Forum Thread: "PWM on Arduino Zero Questions"
  • https://forum.arduino.cc/index.php?topic=330735.0
• Forum thread: "How this timer even works ?"
  • https://forum.arduino.cc/index.php?topic=396396.0
• https://www.hackster.io/voske65/high-speed-pwm-on-arduino-atsamd21-859b06
• http://www.ermicro.com/blog/?p=1971
  • Single and dual slope PWM
• Newbie's Guide to AVR PWM
  • https://www.avrfreaks.net/forum/tut-c-newbies-guide-avr-pwm-incomplete?name=PNphpBB2&file=viewtopic&t=68302
• Smoothly Changing a Timer’s Frequency on the Arduino Zero
• https://gist.github.com/nonsintetic/ad13e70f164801325f5f552f84306d6f
• https://arduino.stackexchange.com/questions/41569/arduino-zero-timer-setup
• SAMD21 Timer library for the Arduino Zero
  • https://github.com/avandalen/avdweb_SAMDtimer
  • https://forum.arduino.cc/index.php?topic=454243.0
• https://github.com/adafruit/Adafruit_ZeroTimer

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