Microchip datasheet in PDF format, 2.87 MB, for the PIC16F872 flash microcontroller, a 28-pin member of the PIC16F87x line. The document includes the pin diagram, memory map, data EEPROM, ADC, timers, serial port module, configuration word and electrical specifications. Technicians consult it to locate supply, reset, oscillator and ICSP pins, measure signal levels on a faulty board and plan reading or reprogramming the firmware. Check code-protect settings, since a protected chip may not give a usable backup.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @datasheet. Enginerys does not host this file.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.