“I love this board. Perfect for prototyping. Adafruit's Qt-py series will also fit. The display and RTC are standard components, and since I prefer Grove to Stemma/Qt anyhow the additional Grove-connectors are always in use.”
“Seeeduino's documentation is sparse and incomplete. In particular, there is no Arduino IDE library package for the expansion board itself, only for the Seeeduino XIAO. It appears that the on-board Real Time Clock's data will be corrupted whenever the OLED display is used. This problem was reported some time ago but no solution has been forthcoming from Seeeduino.”
“Great little accessory for use with the Seeeduino XIAO. Allows all sorts of development work to be set up quickly and easily with a minimum of soldering and trailing wires. the built in display is perfect for debugging.”
“The expansion board was almost three times the cost of the XIAO but worth every penny. The spring-loaded connectors break out the pads at the rear of the XIAO, providing an easy reset. The board also breaks out Grove connectors for I2C, etc., as well as an OLED display, a real-time clock, an SWD pin, LiPo battery management system and connector and a buzzer. The expansion board is great for development by providing an alternative display for output, debugging, etc: I'm using the board with the NRF24L01 RF transceivers, so the OLED overcomes the limitation of a single Serial Monitor in the IDE.
I do wish, however, Pimoroni also sold the cheaper Grove expansion board for XIAO - much more useful for final-product building where an OLED isn't needed.”