Link：Rimer SBC kit

Description：

A complete single-board computer based on ATSAMD51J20A (ARM Cortex-M4) microcontroller and consists of LCD, 40 keys mechanical keyboard, speaker, microSD card slot, USBC connector, three ports of ESD protected GPIOs, optional battery (flat or 18650).

Initially, this platform was developed to get instant access to serial buses - I2C, SPI, and UART. Also, I used it for rapid firmware development since it runs a FreeRTOS-based shell with access to real-time peripherals yet has high-level services like CLI, SD FAT access, scripting, etc.

Although there are many ARM Cortex-M4 development boards and evaluation systems, they all demand a PC to be programmed and managed. At the same time, Rimer SBC provides you with instant access to all chip peripherals directly from the board.

Key Features

• Microcontroller: Atmel ATSAMD51J20A (ARM Cortex-M4F)
• Memory: 1MB Flash, 256 RAM
• Display: 3.2-inch IPS LCD (240x320 resolution) with optional capacitive touchscreen, running up to 60 FPS
• Input: 40-key keyboard
• Storage: SD card slot,64KB I2C EEPROM
• Audio: Onboard speaker

Connectivity:

• USB 2.0 via USB-C connector
• 1x Serial port (UART, I2C) with 3.3V @ 125mA power output
• 2x 6-lane GPIO ports with 3.3V @ 300mA each and configurable as:
• Digital I/O
• SPI
• UART
• USART
• I2C
• TC
• TCC
• Analog I/O routed to 3.5mm audio jack.

Power:

• External power supply via USB-C
• Battery options:
• 20mm x 60mm LIPO battery with onboard charger
• 16850 battery socket with onboard charger

Firmware + apps 

** It is still in continuous development, so I'm open to suggestions **

ucosR - an operating system based on FreeRTOS. It provides control of the program blocks called interfaces. The CLI has command history (no search yet), looping and piping ability, simple script support and a basic text editor. ucosR repository

Basic-D - a Basic language interpreter with a complete line editor and syntax colouring. 

ZX Spectrum 48K emulator, with a debugger, .z80, and .sna snapshots support.

Implemented Interfaces:

• sys : system hardware control (reboot, off ...)
• utl : command line utility (hex, delay ...)
• set: system settings (colours, volume, font ...)
• aio: analog IO ports control (dac, adc ...)
• dio: digital IO port control (pwr, dir, pin ...)
• sio: serial IO ports control (mode, tx, rx ...)
• eep: EEPROM utilities.
• sd: SD FAT control (ls, rm ...)
• bas: Basic-D interpreter.
• mem: RAM utilities.
• zx: ZX Spectrum 48K emulator.