1. Adafruit METRO M7

The main control chip is NXP’s IMXRT1011, with an ARM Cortex-M7 core. IMXRT1011 is a microcontroller unit (MCU) developed by NXP Semiconductors. It belongs to the i.MX RT series of MCUs based on the Arm Cortex-M7 core. The maximum frequency is 500 MHz.

2. Adafruit METRO 328

The main control chip is ATmega328P, with 32KB of flash memory and 2KB of RAM, running at a frequency of 16MHz, and can be developed using Arduino IDE.

3. Adafruit Metro M0 Express

The main control chip is ATSAMD21G18, with an ARM Cortex-M0+ core, clock frequency of 48MHz. This chip has up to 256K of flash memory (8 times more than Atmega328) and 2K of RAM (16 times more)! This chip has built-in USB, so it has built-in USB to serial programming and debugging capabilities without needing a chip like FTDI. It can be used with CircuitPython and is also very suitable for use in Arduino IDE.

4. Adafruit METRO M4 Express

The main control chip is ATSAMD51, with an ARM Cortex-M4 core, can be developed using Arduino IDE.

• Cortex-M4 core running at 120MHz
• Floating-point support for Cortex M4 DSP instructions
• 512KB flash memory, 192KB RAM
• 32-bit, 3.3V logic and power
• Dual 1MSPS DAC (A0 and A1)
• Dual 1MSPS ADC (8 analog pins)
• 6 hardware SERCOM (I2C, SPI or UART)
• 22 x PWM outputs
• Stereo I2S input/output with MCK pin
• 10-bit parallel capture controller (for camera/video input)

5. Adafruit Metro ESP32

The main control chip is Espressif’s ESP32-S2, can be developed using Arduino IDE.

6. Adafruit METRO ATSAMD51

The main control chip is ATSAMD51, with an ARM Cortex-M4 core, can be developed using Arduino IDE.