The C8051F221-GQR is an 8-bit microcontroller from Silicon Labs with a core processor of 8051 and a speed of 25MHz. It has a program memory size of 8KB (8K x 8) and a RAM size of 256 x 8. The microcontroller supports various connectivity options such as SPI and UART/USART. It also comes with peripherals like Brown-out Detect/Reset, POR, and WDT. The device has a voltage range of 2.7V ~ 3.6V and operates in a temperature range of -40°C ~ 85°C. It comes in a 32-LQFP (7x7) package and has a limited supply and demand status.