Explain the function of the pins PSEN and EA of 8051.
PSEN: PSEN stands for program store enable. In 8051 based system in which an external ROM holds the program code, this pin is linked to the OE pin of the ROM.
EA :EA stands for external access. When the EA pin is linked to Vcc, program fetched to addresses 0000H through 0FFFH are directed to the internal
ROM and program fetches to addresses 1000H by FFFFH are directed to external ROM/EPROM. When the EA pin is grounded, all addresses fetched by program are directed to the external ROM/EPROM.