Seeeduino Wio Terminal

After the minimalistic Xiao board, Seeed continues to explore new options with the Wio Terminal.

This time, the Seeeduino Wio Terminal is more of a complete system. It comes on a stylish white case, brings Grove connectors and relies on a powerful Cortex-M4F SAMD51.

Hardware

The Wio Terminal comes in a compact white case, with

On the front, a 320x240 screen and a 5-way joystick,
On the back, a 40-pin Raspberry Pi compatible connector.

The screen is protected by a glass and does not feature touch.

The battery expansion connects to the Wio Terminal underneath and features a 650 mAh LiPo.

Both the Wio Terminal and the battery expansion feature magnets to place the case on a metallic surface, like a refrigerator.

However, the two cases are misaligned by 1 mm both vertically and horizontally. The schematics show features not implemented, like screen touch for the Wio Terminal and battery gauge for the battery expansion .

The Atmel ATSAMD51P19A powers the board. It is a Cortex-M4F, runs up to 120 MHz, and comes with 512 KB Flash and 192 KB RAM, plus 4 MB of external Flash.

The RTL8720 manages the WiFi and BLE connections.

Other included circuits include the LIS3DHTR accelerometer, a microphone and a buzzer, a light sensor and an infrared emitter.

On the top,

Wio Terminal: three buttons,
Battery expansion: nothing.

On the bottom,

Wio Terminal: two Grove connectors (GPIOs and I²C port) along with USB-C,
Battery expansion: two Grove connectors (UART and I²C ports) along with USB-C (charging only).

On the left,

Wio Terminal: a switch and a microSD-card slot,
Battery expansion: two GPIO Grove connectors.

On the right,

Wio Terminal: a slot for a flat cable,
Battery expansion: two GPIO Grove connectors.

On the front,

Wio Terminal: microphone and buzzer, LCD display and 5-way joystick,
Battery expansion: 40-pin male connector.

On the rear,

Wio Terminal: light sensor and infrared emitter (below the glass window), 40-pin female connector,
Battery expansion: 40-pin female connector.

Software

Seeed provides a specific boards package for the Arduino IDE and a large Wiki section offers a very clear documentation. The board is also supported by embedXcode. I haven't tested external debugging yet.

One of the interesting part of the board is the multiple offer for uploading the firmware.

Standard with serial through USB,
Use the UF2 protocol to copy-paste the executable binary to the board acting as a mass storage device named Arduino.

During my tests, I've faced some issues when uploading UF2. It often required a manual reset.

The screen and the microFlash-card use dedicated SPI ports, for optimal speed. The implementation of my LCD_screen Library Suite was especially fast.

The Wiki goes through all the features, except BLE, with the relevant libraries and examples.

The RTL8720 manages the WiFi and BLE connections. A very clear procedure explains how update the RTL8720 firmware. I faced no issues, except that the utility runs on Windows only for the moment.

Drag-and-drop the executable
onto the volume to flash the board

Debugging

The Seeeduino Wio Terminal exposes the SWD signals through SWCLK and SWDIO pads.

However, they are difficult to access. First option requires to open the case and remove the circuit board. Second option allows to shunt the SWCLK and SWDIO signals to the I²C Grove connector, but the explanations about possible conflicts are not clear.

I would have expected the battery expansion to expose the debugging signals with a standard 2x5 0.05" SWD connector. So I haven't tested external debugging with embedXcode and my Segger J-Link Edu.

Conclusion

At less than USD30 or USD40 with the battery expansion, the Seeeduino Wio Terminal brings great value, with a compact form-factor, a fast and powerful Cortex-M4F, a decent screen and IoT capabilities.

The battery expansion turns it into an autonomous edge computing solution, perfect with the Grove connectors and the WiFi.

The USB-C to USB-A cable is included.

What could be next iteration? I would welcome a larger screen 480x320 with capacitive touch, a SWD connector for debugging, OTA upload, battery monitoring and support from Microsoft MakeCode Arcade.

Pros

Powerful and affordable board
Grove connectors

Cons

SWD not easy to use for debugging
5-way joystick instead of touch
No battery monitoring

Wrap-Up

Great value