Microprocessors Interview Questions of part --17

Microprocessors Interview Questions of part --17

Can an RC circuit be used as clock source for 8085?
Yes, it can be used, if an accurate clock frequency is not required. Also, the component cost is low compared to LC or Crystal
What are Hardware interrupts?
TRAP, RST7.5, RST6.5, RST5.5, INTR
Which interrupt has the highest priority?
TRAP has the highest priority
What is Tri-state logic?
Three Logic Levels are used and they are High, Low, High impedance state. The high and low are normal logic levels & high impedance state is electrical open circuit conditions. Tri-state logic has a third line called enable line.
How many interrupts are there in 8085?
There are 12 interrupts in 8085.
What does Quality factor mean?
The Quality factor is also defined, as Q. So it is a number, which reflects the lossness of a circuit. Higher the Q, the lower are the losses.
What happens when HLT instruction is executed in processor?
The Micro Processor enters into Halt-State and the buses are tri-stated.
What is Stack Pointer?
Stack pointer is a special purpose 16-bit register in the Microprocessor, which holds the address of the top of the stack.
In 8085 name the 16 bit registers?
Stack pointer and Program counter all have 16 bits.
What are the various flags used in 8085?
Sign flag, Zero flag, Auxiliary flag, Parity flag, Carry flag.
What are Software interrupts?
RST0, RST1, RST2, RST3, RST4, RST5, RST6, RST7.
Which interrupt is not level-sensitive in 8085?
RST 7.5 is a raising edge-triggering interrupt.
What are level-triggering interrupt?
RST 6.5 & RST 5.5 are level-triggering interrupts.
What is the RST for the TRAP?
RST 4.5 is called as TRAP.
What is Program counter?
Program counter holds the address of either the first byte of the next instruction to be fetched for execution or the address of the next byte of a multi byte instruction, which has not been completely fetched. In both the cases it gets incremented automatically one by one as the instruction bytes get fetched. Also Program register keeps the address of the next instruction