What this 28-DIP PIC brings to the board
The Microchip PIC16F873-20/SP is an 8-bit PIC® 16F series microcontroller in a through-hole 28-DIP (0.300", 7.62mm) package, designed for legacy through-hole PCB assembly, prototyping, and rework-friendly designs. It runs at 20 MHz with 7 KB (4K x 14) Flash program memory, 192 x 8 bytes of RAM, and 128 x 8 bytes of EEPROM for non-volatile data storage.
The 20 MHz core speed sets the instruction cycle at 200 ns (5 MIPS), adequate for UART polling at 115.2 kbps, I²C at 400 kHz, and SPI clocking up to 5 MHz without external oscillators (the oscillator type is external,). The 7 KB Flash holds moderate firmware — think PID loops, Modbus slaves, or keypad scanners — while the 128 x 8 EEPROM stores calibration constants or configuration bytes without wearing the Flash. The 5-channel 10-bit ADC covers analog inputs like thermistors or potentiometers. Brown-out detect, POR, PWM, and WDT are on-chip, reducing external supervisor ICs.
Sourcing this part for your BOM
If your design requires a 16-bit core or more I/O, the PIC24FJ256GA106-I/MR or PIC24FV16KA304-I/PT are architectural alternatives, though they shift to surface-mount packages and lower supply voltages.