in the PIC
family of controllers, produced by Microchip Technology
The PIC16F84A is an improved version of the PIC16C84
, and almost completely compatible, with better program security and using flash memory
instead of EEPROM
memory for program memory. The PIC16F84A has 68 bytes of RAM whilst the PIC16C84 has 36 bytes. Both versions feature a wide voltage range, low power consumption, internal timer, and PIC I/O
Since the two chips are so similar they are often referred to by the term PIC16x84 (x is used as a wildcard when referring to chips).
The PIC16C84 was the first PIC microcontroller to feature a serial programming algorithm and EEPROM memory, both of which lend themselves to hobby use: only a simple and cheap programmer is required to program, erase and reprogram the chip. As PIC16C84 supplies became limited due to it being discontinued, the PIC16F84 became popular as an almost drop in replacement. New programming software was needed as the programming algorithm is different but the programming hardware required was the same.
The PIC16x84 microcontroller is a member of Microchip's 14-bit series (the instruction word size is 14 bits for all instructions), making the '84 a good development prototype for other similar but cheaper one-time-programmable 14-bit devices.