The ATMEGA324A-CU: At 20 MHz, the AVR single-cycle core executes most instructions in one clock. Connectivity includes I2C, SPI, and UART/USART.
The 1.8V to 5.5V supply range means the same BOM can run from a 3.3V regulated rail or a 5V industrial bus, and the brown-out detect can be configured to hold the MCU in reset until the rail is stable — a key feature for battery-powered or capacitor-fed supplies.
Package and footprint notes for the 49-VFBGA
Package is 49-VFBGA (5x5 mm). Mounting type is surface mount.
The ROHS3 compliance is current.