Historically neither of them made any microcontrollers. Arduino shipped Atmel and Raspberry Pi chips. Adafruit has boards with a variety of microcontrollers fro

Historically neither of them made any microcontrollers. Arduino shipped Atmel and Raspberry Pi chips. Adafruit has boards with a variety of microcontrollers from various brands on them. This is different now that Arduino is Qualcomm-owned and ships Qualcomm silicon, of course.