Week06 Group Assignmnet - Compare Various Microcontrollers

micro:bit

The micro:bit is an easily programmable Single Board Computer (SBC) that contains an application processor with a variety of on-chip peripherals. Detailed information can be found at the hardware introduction page.

Basic specs of the micro:bit hardware are:

• nRF52 Application Processor
  • Model: Nordic nRF52833
  • Core variant: Arm Cortex-M4 32 bit processor with FPU
• Buttons:
• GPIO Pins:
• Accelerometer:
• Magnetometer:
• Temperature Sensor:
• LED Matrix:
• Bluetooth:
• Power:

ATmega328p

The ATmega328p is a high performance, low power AVR® 8-bit microcontroller, it is used as the core of the widely used Arduino Uno development borad. Some basic specs are listed below, more information can be found on the Microchip product page and its datasheet.

• High performance, low power AVR® 8-bit microcontroller
• 32KB ISP Flash memory
• 1024B EEPROM
• 2KB SRAM
• 23 general purpose I/O lines
• serial programmalble USART
• byte-oriented Two-Wire serial interface (I2C)
• SPI serial port
• 6-channel 10-bit A/D converter (8-channels in TQFP and QFN/MLF packages)
• Operating voltage:
  • 2.7V - 5.5V
• Temperature range:
  • Automotive temperature range: -40℃ to +125℃
• Speed grade:
  • 0 to 8MHz at 2.7 to 5.5V (automotive temperature range: -40℃ to +125℃)
  • 0 to 16MHz at 4.5 to 5.5V (automotive temperature range: -40℃ to +125℃)
• Low power consumption
  • Active mode: 1.5mA at 3V - 4MHz
  • Power-down mode: 1μA at 3V

Pinout reference of ATmega328p DIP package from an alternative Arduino Core Minicore

Program ATmega328p

The Arduino Uno comes with the USB serial interface that can be use to upload program from the computer. But the ATmega328p chip itself doesn't have that, and it needs a programmer to upload the program to the board.

Since the Arduino Uno uses the ATmega328p as its microcontroller, the Arduino IDE and its library can be used to write ATmega328p compatible code. The only difference is that the Arduino Uno has a 16MHz external crystall oscillator connected to the chip and the chip is running at a different speed if we only use the 8MHz internal oscillator of the ATmega328p itself.

According to the documentation from Arduino, we can load a diffrent board configuration for the ATmega328p to write code for the ATmega328p without the external oscillator, and we can use another Arduino Uno to act as the programmer to upload code to the chip, as some of us tried on week04 and this week's personal assignment.

Arduino Uno

Arduino Uno

RP2040

The RP2040 is a microcontroller is designed by Raspberry Pi, product page and datasheet.

Basic specs:

• Dual ARM Cortex-M0+ @ 133MHz
• 264kB on-chip SRAM in six independent banks
• Support for up to 16MB of off-chip Flash memory via dedicated QSPI bus
• DMA controller
• Fully-connected AHB crossbar
• Interpolator and integer divider peripherals
• On-chip programmable LDO to generate core voltage
• 2 on-chip PLLs to generate USB and core clocks
• 30 GPIO pins, 4 of which can be used as analogue inputs
• Peripherals
  • 2 UARTs
  • 2 SPI controllers
  • 2 I2C controllers
  • 16 PWM channels
  • USB 1.1 controller and PHY, with host and device support
  • 8 PIO state machines

Seeed Xiao RP2040

The RP2040 microcontroller can also be programmed by the Arduino platform. We are using the Seeed Studio Xiao RP2040 as the develpment board for RP2040, and Seeed Studio has official documentation for programm the Xiao RP2040 via Arduino IDE.

Follow the instruction and installed the Arduino core for RP2040 to Arduino IDE, we can write code for the RP2040 microcontroller using the same set of API to control the board.

As the product page stated, the Xiao RP2040 has the following specs:

• Flash Memory: 2MB
• SRAM: 264KB
• Digital I/O Pins: 11
• Analog I/O Pins: 4
• PWM Pins: 11
• I2C interface: 1
• SPI interface: 1
• UART interface: 1
• Power and downloading interface: Type-C
• Power: 3.3V/5V DC
• Dimensions: 20×17.5×3.5mm

Due to its small formfactor, the Xiao RP2040 doesn't expose all the peripheral capabilities of the RP2040, and an error in the documentation led to some confusion when we were testing the board.

Seeed Studio Xiao RP2040 Schematic

ESP32

ESP32 Datasheet

The development board we have for the ESP32 chip is similiar to the official ESP32-DevKitC dev board from Espressif but with a USB Type-C connector. It has a ESP32-WROOM-32 at its core.