Embedded Systems Interview Questions
Questions Answers Views Company eMail

Difference between 80286 and 80287

Mascot,

2 6087

In a processor these are 120 instructions . Bits needed to impliment this instructions [a] 6 [b] 7 [c] 10 [d] none

Wipro,

2 6683

In 8085 microprocessor READY signal does.which of the following is incorrect statements [a]It is input to the microprocessor [b] It sequences the instructions

Wipro,

2 6155

Return address will be returned by function to

Wipro,

2 3237

load a mul a store t1 load b mul b store t2 mul t2 add t1 then the content in accumulator is

Wipro,

2 4361

In 8085 microprocessor READY signal does.which of the following is incorrect statements [a]It is input to the microprocessor [b] It sequences the instructions

Wipro,

4 6250

what is conductance and valence band?

1 2703

What is Fermi level?

5 4101

How does Vbe and Ic change with temperature?

Qualcomm,

1617

If the substrate doping concentration increase, or temperature increases, how will Vt change? it increase or decrease?

1041

what is Channel length modulation?

Intel,

1342

what is the doping?

5 2653

How does a pn junction works?

Wipro,

1 3172

What is the depletion region?

1 2513

Tell me the parameters as many as possible you know that used to character an amplifier?

774



Un-Answered Questions { Embedded Systems }

What types of I/O have you designed? What were their size? Speed? Configuration? Voltage requirements?

860


If not into production, how far did you follow the design and why did not you see it into production?

693


This program is in verilog and need help to get it working correctly. This is the code i have so far. Please help. Simple testbench would be great. Thanks\ 'define vend_a_drink {D,dispense,collect} = {IDLE,2'b11}; module drink_machine(nickel_in, dime_in, quarter_in, collect, nickel_out, dime_out, dispense, reset, clk) ; parameter IDLE=0,FIVE=1,TEN=2,TWENTY_FIVE=3, FIFTEEN=4,THIRTY=5,TWENTY=6,OWE_DIME=7; input nickel_in, dime_in, quarter_in, reset, clk; output collect, nickel_out, dime_out, dispense; reg collect, nickel_out, dime_out, dispense; reg [2:0] D, Q; /* state */ // synopsys state_vector Q always @ ( nickel_in or dime_in or quarter_in or reset ) begin nickel_out = 0; dime_out = 0; dispense = 0; collect = 0; if ( reset ) D = IDLE; else begin D = Q; case ( Q ) IDLE: if (nickel_in) D = FIVE; else if (dime_in) D = TEN; else if (quarter_in) D = TWENTY_FIVE; FIVE: if(nickel_in) D = TEN; else if (dime_in) D = FIFTEEN; else if (quarter_in) D = THIRTY; TEN: if (nickel_in) D = FIFTEEN; else if (dime_in) D = TWENTY; else if (quarter_in) 'vend_a_drink; TWENTY_FIVE: if( nickel_in) D = THIRTY; else if (dime_in) 'vend_a_drink; else if (quarter_in) begin 'vend_a_drink; nickel_out = 1; dime_out = 1; end FIFTEEN: if (nickel_in) D = TWENTY; else if (dime_in) D = TWENTY_FIVE; else if (quarter_in) begin 'vend_a_drink; nickel_out = 1; end THIRTY: if (nickel_in) 'vend_a_drink; else if (dime_in) begin 'vend_a_drink; nickel_out = 1; end else if (quarter_in) begin 'vend_a_drink; dime_out = 1; D = OWE_DIME; end TWENTY: if (nickel_in) D = TWENTY_FIVE; else if (dime_in) D = THIRTY; else if (quarter_in) begin 'vend_a_drink; dime_out = 1; end OWE_DIME: begin dime_out = 1; D = IDLE; end endcase end end always @ (posedge clk ) begin Q = D; end endmodule

1938


I have code and test bench however it is not working porperly. Need help to get it working. module fsm(clock,reset,coin,vend,state,change); \\these are the inputs and the outputs. input clock; input reset; input [2:0]coin; output vend; output [2:0]state; output [2:0]change; \\i need to define the registers as change,coin and vend reg vend; reg [2:0]change; wire [2:0]coin; \\my coins are declared as parameters to make reading better. parameter [2:0]NICKEL=3’b001; parameter [2:0]DIME=3’b010; parameter [2:0]NICKEL_DIME=3’b011; parameter [2:0]DIME_DIME=3’b100; parameter [2:0]QUARTER=3’b101; \\MY STATES ARE ALSO PARAMETERS . I DONT WANT TO MAKE YOU READ \\IN MACHINE LANGUAGE parameter [2:0]IDLE=3’b000; parameter [2:0]FIVE=3’b001; parameter [2:0]TEN=3’b010; parameter [2:0]FIFTEEN=3’b011; parameter [2:0]TWENTY=3’b100; parameter [2:0]TWENTYFIVE=3’b101; \\AS ALWAYS THE STATES ARE DEFINED AS REG reg [2:0]state,next_state; \\MY MACHINE WORKS ON STATE AND COIN always @(state or coin) begin next_state=0; \\VERYFIRST NEXT STATE IS GIVEN ZERO case(state) IDLE: case(coin) \\THIS IS THE IDLE STATE NICKEL: next_state=FIVE; DIME: next_state=TEN; QUARTER: next_state=TWENTYFIVE; default: next_state=IDLE; endcase FIVE: case(coin) \\THIS IS THE SECOND STATE NICKEL: next_state=TEN; DIME: next_state=FIFTEEN; QUARTER: next_state=TWENTYFIVE; //change=NICKEL default: next_state=FIVE; endcase TEN: case(coin) \\THIS IS THE THIRD STATE NICKEL: next_state=FIFTEEN; DIME: next_state=TWENTY; QUARTER: next_state=TWENTYFIVE; //change=DIME default: next_state=TEN; endcase FIFTEEN: case(coin) \\THIS IS THE FOURTH STATE NICKEL: next_state=TWENTY; DIME: next_state=TWENTYFIVE; QUARTER: next_state=TWENTYFIVE; //change==NICKEL_DIME default: next_state=FIFTEEN; endcase TWENTY: case(coin) \\THIS IS THE FIFTH STATE NICKEL: next_state=TWENTYFIVE; DIME: next_state=TWENTYFIVE; //change=NICKEL QUARTER: next_state=TWENTYFIVE; //change==DIME_DIME default: next_state=TWENTY; endcase TWENTYFIVE: next_state=IDLE; \\THE NEXT STATE HERE IS THE RESET default : next_state=IDLE; endcase end always @(clock) begin \\WHENEVER I GIVE A RESET I HAVE TO MAKE THE STATE TO IDLE AND VEND TO 1 if(reset) begin state <= IDLE; vend <= 1’b0; // change <= 3’b000; end \\THE CHANGE ALSO HAS TO BECOME NONE else state <= next_state; case (state) \\HERE WE DECIDE THE NEXT STATE \\ALL THE STATES ARE DEFINED HERE AND THE OUTPUT IS ALSO GIVEN IDLE: begin vend <= 1’b0; change <=3’d0; end FIVE: begin vend <= 1’b0; if (coin==QUARTER) change <=NICKEL; else change <=3’d0; TEN: begin vend <= 1’b0; if (coin==QUARTER) change <=DIME; else change <= 3’d0; FIFTEEN : begin vend <= 1’b0; if (coin==QUARTER) change <=NICKEL_DIME; else change TWENTY : begin vend <= 1’b0; if (coin==DIME) change <=NICKEL; else if (coin==QUARTER) TWENTYFIVE : begin vend <= 1’b1; change <=3’d0; end default: state <= IDLE; endcase end endmodule module test; \\THE INPUT IN THE FSM MODULE ARE REG HERE reg clock,reset; reg [2:0]coin; \\THE OUTPUT IN THE FSM MODULE ARE WIRES HERE wire vend; wire [2:0]state; wire [2:0]change; \\THE PARAMETERS AGAIN FOR THE COIN AND STATE parameter [2:0]IDLE=3’b000; parameter [2:0]FIVE=3’b001; parameter [2:0]TEN=3’b010; parameter [2:0]FIFTEEN=3’b011; parameter [2:0]TWENTY=3’b100; parameter [2:0]TWENTYFIVE=3’b101; parameter [2:0]NICKEL=3’b001; parameter [2:0]DIME=3’b010; parameter [2:0]NICKEL_DIME=3’b011; parameter [2:0]DIME_DIME=3’b100; parameter [2:0]QUARTER=3’b101; \\I MONITOR THE TIME,DRINK,RESET,CLOCK,STATE AND CHANGE FOR CHANGES. initial begin $display("Time\tcoin\tdrink\treset\tclock\tstate\tchange"); $monitor("%g\t%b\t%b\t%b\t%b\t%d\t% d",$time,coin,vend,reset,clock,state,change); \\NEW FEATURE: MY MACHINE HAS THE FACILITY TO DUMP VARIABLES SO THAT \\ I CAN VIEW THEM USING A VCD VIEWER. $dumpvars; $dumpfile("file.vcd"); // Dump output file. \\THIS IS WHERE THE COINS ARE ADDED. clock=0; reset=1; \\FIRST LETS RESET THE MACHINE #2 reset=0; coin=NICKEL; \\CHECK FOR STATE 1 #2 reset=1; coin=2’b00; #2 reset=0; coin=DIME; \\RESET AGAIN AND CHECK FOR STATE 2 #2 reset=1; coin=2’b00; #2 reset=0; \\RESET AGAIN AND CHECK FOR STATE 5 coin=QUARTER; #2 reset=1; coin=2’b00; #2 reset=0; \\RESET AGAIN AND CHECK FOR STATE 5 coin=NICKEL; #2 coin=NICKEL; #2 coin=NICKEL; #2 coin=NICKEL; #2 coin=NICKEL; #2 reset=1; coin=2’b00; #2 reset=0; \\RESET AGAIN AND CHECK FOR STATE 5 AND SO ON coin=NICKEL; #2 coin=DIME; #2 coin=DIME; #2 reset=1; coin=2’b00; #2 reset=0; coin=NICKEL; #2 coin=DIME; #2 coin=QUARTER; #2 reset=1; coin=2’b00; #2 reset=0; coin=NICKEL; #2 coin=NICKEL; #2 coin=NICKEL; #2 coin=DIME; #2 reset=1; coin=2’b00; #2 reset=0; coin=NICKEL; #2 coin=NICKEL; #2 coin=NICKEL; #2 coin=NICKEL; #2 coin=DIME; #2 reset=1; coin=2’b00; #2 reset=0; coin=NICKEL; #2 coin=NICKEL; #2 coin=QUARTER; #2 reset=1; coin=2’b00; #2 reset=0; coin=NICKEL; #2 coin=QUARTER; #2 reset=1; coin=2’b00; #2 $finish; end \\THE CLOCK NEEDS TO TICK EVERY 2 TIME UNIT always #1 clock=~clock; //always @(state) // coin=!coin; initial begin if (reset) coin=2’b00; end \\THIS IS WHERE I INSTANTIATE THE MACHINE fsm inst1(clock,reset,coin,vend,state,change); endmodule

2090


Explain the working of 4-bit Up/down Counter?

2710


If the substrate doping concentration increase, or temperature increases, how will Vt change? it increase or decrease?

1041


What is the critical path in a SRAM?

1471


Explain the Charge Sharing problem while sampling data from a Bus?

794


Process technology? What package was used and how did you model the package/system? What parasitic effects were considered?

1509


If an/ap = 0.5, an/ap = 1, an/ap = 3, for 3 inverters draw the transfer characteristics?

889


what is the command/instruction in ARM that does not do anything or does not execute any instruction ? (except NOP instruction)

1748


Are you familiar with the term MESI?

1047


PROVIDE ME NOTES ON EMBEDDED TCHNLOGY

1516


Draw the Layout of an Inverter?

816


Tell me how MOSFET works.

928