8255 IC BLOCK DIAGRAM
8255A - Programmable Peripheral Interface - Tutorialspoint
8255A has three ports, i.e., PORT A, PORT B, and PORT C. Port A contains one 8-bit output latch/buffer and one 8-bit input buffer. Port B is similar to PORT A. Port C can be split into two parts, i.e. PORT C lower (PC0-PC3) and PORT C upper (PC7-PC4) by the control word.
Draw & explain block diagram of 8259 PIC.
Fig below shows the internal block diagram of the 8259A. It includes eight blocks: data bus buffer, read/write logic, control logic, three registers (IRR, ISR and IMR), priority resolver, and cascade buffer. Data Bus Buffer: The data bus buffer allows the 8085 to send control words to the 8259A and read a status word from the 8259A. The 8•bit data bus buffer also allows the 8259A to send interrupt opcode