Micro Controller Interview Questions - Part 4
What is IMR(Interrupt mask register) ?IMR stores the masking bits of the interrupt lines to be masked. This register can be programmed by an operation command word (OCW).
What is priority resolver ?It determines the priorities of the bits set in the Interrupt request register (IRR), bit corresponding to the highest priority interrupt input is set in the ISR during INTA input.
What is the use of IRR ?The interrupt request register is used to store all the interrupt levels which are requesting the service. The eight interrupt inputs sets corresponding bits of the Interrupt Request Register upon the service request.
What is Interrupt service register(ISR) ?The interrupt service register stores all the levels that are currently being serviced.
What is the difference between SHLD and LHLD ?
What is the difference between STAX and LDAX ?
Write an assembly language program to transfer data from memory block B1 to memory block B2 ?MVI C,0AH; Initialize counter
LXI H, 2200H; Initialize source memory pointer
LXI D, 2300H; Initialize destination memory pointer
Loop: MOV A,M; Get byte from source memory block
STAX D; Store byte in the destination memory block
INX H; Increment source memory pointer
INX D; Increment destination memory pointer
DCR C; Decrement counter
JNZ Loop ; If counter ? 0 repeat
What are the types of branching instructions ?
Write an assembly language program to add 2 BCD numbers ?LXI H,2200H; Initialize pointer
MOV A,M ; Get the first number
INX H; Increment the pointer
ADD M ; Add two numbers
DAA ; Convert HEX to valid
BCD STA 2300; store the result
Explain the instruction LXI rp,data (16) ?LXI rp, data(16) : Load 16 :bit immediate data to specified register pair or stack pointer. The rp is 16 bit register pairs such as BC, DE, HL or stack pointer.
Micro Controller Interview Questions - Part 5 >>>