
PERIPHERAL INTERFACING – II 377
MOV BL, AL ;copy it to BL
MOV BH, 0 ;BH = 0
ADD SI, BX ;add BX to SI
MOV AL, [SI] ;take corresponding display code
OUT DATR, AL ;send it to data register
JMP NEXT ;continue for more keys
is program displays every key that is pressed. After 8 entries, the FIFO drops the earliest
entries and continues the displaying of the keys pressed.
10.3 | The Programmable Interrupt Controller (PIC) 8259
10.3.1 | Introduction
Before trying to understand the description and working of the programmable interrupt
controller (PIC), it will be worthwhile to read Section 8.1 to get a precise and clear understanding ...