Top Embedded Systems Interview Questions :: Top Embedded Systems Interview Questions en-us What is a program counter? What is its use? It is a 16 bit special function register in the 8085 microprocessor.It keeps track of the the next memory adderess of the instruction that is to be executed once the execution of the current instruction is completed.In other words, it holds t Differences between DRAM and SRAM? dram consist of only one transistor and then it is a volatile is refreshed periodically otherswise stored informations are deleted. sram consists of five or six transistors and it is also a volatile memory, if power is shutoff or rew Differences between D-Latch and D flip-flop? D-latch is level Triggering and D Flip Flop is Edge triggering. Define threshold voltage? threshold voltage is defined as the minimum voltage that required to make the transistor ON. transistor may be either NMOS or PMOS.For NMOS the value of threshold voltage is positive value and for PMOS the value of threshold voltage is negati What are the different addressing modes in 8085? Various formats of specifying the operands are called addressing modes. 1) Direct, (ex: IN/OUT Port#) (# - port number) 2) Immediate, (ex: MVI R,Data) (R-register) 3) Register, (ex: MOV Rd,Rs) (Rd- destination Register, Rs- source Register) 4) What is ALE? Explain the functions of ALE in 8085. address latch the case of microcontroller (8051) & microprocessor 8085 the data line & low order 8 bit address lines are order to geting address from this line we uses a latch.ALE is the line connected to this l What is the function of accumulator? An accumulator is an 8-bit register that is a part of ALU (Arithmatic-Logic Unit) of a processor.It is used for temporary storage of 8-bit data and to perform arithmatic operations like addition,subtraction,multiplication,division or logical oper What are the different flags in 8085? 8085 microprocessor has a set 5 flip flops which serves as the status flags & they are : Sign Flag ,Carry Flag, Auxillary Carry Flag, Parity Flag & Zero Flag What is PSW? program status word.... a reg in the microcontroller/microprocessor s showing the current current status of alu operation eg: if a carry is generated after an alu operation ,the corresponding carry flag bit in this reg will set 1. like if t What is LVS, DRC? LVs means LAyout versus schematic -method to check the correctness of ur layout designed by cross checking with netlist generated from schematic using the tool. DRC means....?? what do you mean by embedded system? It's a combination of software and hardware Which are embedded by Kiel compiler.It 1s a device that do a specific task. What are the functions of RIM, SIM, IN? RIM FUNCTION: READ INTERRUPT MASK it will check the wheather interrut is mask or not. SIM FUNCTION:SET INTERRUPT MASK it Used to mask the hardware interrupts IN i dont know What is the most complicated/valuable program you written in C/C++? hello world program 7. What are tri-state devices and why they are essential in a bus or In a multiplexed bus system, many devices are connected to a common bus. If 2 or more devices attempt to use the bus at the same time , then data will be lost. Thus only one one device must be allowed to use the bus at a time. O e method is t What is Noise Margin? Explain the procedure to determine Noise Margin In digital logic design the general representation of input and output are High and low level (1's and 0's). In actual case when the input signal transitions the output switches to full swing before the input has reached its full swin