8259 Programmable Interrupt Controller The Intel 8259A programmable Interrupt Controller (PIC) is one of the most common interrupt controller used in IBM PCs. It can handle eight vectored priority interrupts for the CPU. It is a 28 pin DIP package and requires a single +5V DC supply for its operation. It is designed to minimize […]

Interrupts Interrupt is one of the most common methods for an external device to communicate with the processor. In small systems, for example, we might read ASCII characters on interrupt basis, count interrupt from a timer to produce real time clock or seconds, minutes and hours; detect several emergency conditions on interrupt basis. Figure-1 below […]

8255 Programmable Peripheral Interface 8255 is a programmable peripheral interface IC which is used as an interface between the external device and the microprocessor for parallel communication. This IC is a 40-pi IC having three ports known as Port-A(PA), Port-B(PB) and Port-C(PC). these ports can operate in various modes. the complete details is given in […]