40-DIP through-hole — field-swappable, no hot-air needed
The Microchip PIC18F4420-I/P is an 8-bit PIC core MCU in a 40-pin DIP package — the classic wide DIP that fits standard sockets and breadboards. The 13-channel 10-bit ADC brings analog sensor inputs directly onto the microcontroller, saving an external converter.
The 40 MHz clock rate is the top speed for the PIC18F family. On a single-cycle instruction pipeline that means most operations execute in 100 ns. That is enough headroom to run a UART at 115200 baud with bit-banged SPI on the side, or to service a PWM loop at tens of kilohertz without jitter. The flash wait states are handled automatically at this speed — no BOOT0 strapping dance like on some ARM parts.
Peripherals and connectivity — what is on the die
The peripheral set includes Brown-out Detect/Reset, High/Low Voltage Detect (HLVD), Power-on Reset (POR), two PWM channels, and a Watchdog Timer (WDT). For serial communication it has I²C, SPI, and a UART/USART module — enough to talk to sensors, displays, and serial EEPROMs without external logic. The 36 I/O pins give you room for a parallel LCD bus plus a keypad matrix and still leave a few spare lines for debug LEDs.
The ROHS3 compliance is current.