01․ EPROMs are preferred for storing programs while developing new microprocessor based system. Because of their
EPROM(Erasable Programmable Read Only Memory) has non-volatile, erasable and programmable characteristics.
02․ When any data transfer instruction, to transfer the data from memory to microprocessor, is executed the condition flags are
Data transfer operation does not affect any of the flags in 8085 microprocessor.
03․ Let the content of accumulator and register B be 0000 0100 and 0100 0000 respectively before execution of instruction SUB B. The content of accumulator after the execution of this instruction will be
SUB B allows subtraction of content B from A and the result is stored in the accumulator. In the given problem we have to subtract 0100 0000 from 0000 0100. Hence the content of the accumulator after execution the given instruction will be 11000100.
04․ Let the content of register C be 00000000 before the instruction DCR C is executed. The content of register C after the after the execution of this instruction will be
DCR C instruction allows C to decrement the content of register C by 1. Binary of 1 is 00000001. We have to subtract 00000001 from 00000000.
05․ In 8085 microprocessor based system maximum possible number of input/output devices can be connected using I/O mapped I/O technique is
Using I/O mapped I/O technique 256 input device and 256 output device i.e. total 512 input/output devices can be connected to the microprocessor.
06․ Cycle stealing mode of DMA operation involves
Cycle stealing mode of DMA operation takes place while the microprocessor is executing a program and an interface circuit takes over control of address, data and control buses when not in use by microprocessor.
07․ Which of the following is not true during the execution of an interrupt service routine, which does not contain any EI instructions
EI (Enable Interrupt) instruction should be provided at the beginning of any program so that it can respond to any interrupts. If EI is not provided in the program then microprocessor cannot be interrupted by any interrupt.
08․ The reason for the presence of ALE pin in 8085, but not in 6800 is that
8085 has multiplexed bus which acts as address bus as well as data bus(AD0-AD7). So ALE is required to indicate status of the buses.
09․ Which of the following interrupt is both level and edge sensitive?
TRAP is one and only interrupt having both level and edge sensitive triggering.
10․ The addressing mode in instruction PUSH B is
The addressing mode in instruction PUSH B is register indirect. The contents of the source registers are not altred after the PUSH instruction.