Q:
What is null modem connection?
belongs to collection: COMPUTER ARCHITECTURE - 8051 MICROCONTROLLER MCQ
COMPUTER ARCHITECTURE - 8051 MICROCONTROLLER MCQ
- 8051 series of micro controllers are made by which of the following companies?
- AT89C2051 has RAM of:
- 8051 series has how many 16 bit registers?
- When 8051 wakes up then 0x00 is loaded to which register?
- When the micro controller executes some arithmetic operations, then the flag bits of which register are affected?
- How is the status of the carry, auxiliary carry and parity flag affected if write instruction
- How are the bits of the register PSW affected if we select Bank2 of 8051?
- If we push data onto the stack then the stack pointer
- On power up, the 8051 uses which RAM locations for register R0- R7
- How many bytes of bit addressable memory is present in 8051 based micro controllers?
- DJNZ R0,label is how many bit instruction?
- JZ, JNZ, DJNZ, JC, JNC instructions monitor the bits of which register ?
- Calculate the jump code for again and here if code starts at 0000H
- When the call instruction is executed the top most element of stack comes out to be
- LCALL instruction takes
- Are PUSH and POP instructions are a type of CALL instructions?
- What is the time taken by one machine cycle if crystal frequency is 20MHz?
- Find the number of times the following loop will be executed
- What is the meaning of the instruction MOV A,05H ?
- Does the two instructions mean the same?
- To initialise any port as an output port what value is to be given to it?
- Which out of the four ports of 8051 needs a pull-up resistor for using it is as an input or an output port?
- Which of the ports act as the 16 bit address lines for transferring data through it?
- Which of the following registers are not bit addressable?
- Which instruction is used to check the status of a single bit?
- Which addressing mode is used in pushing or popping any element on or from the stack?
- Which operator is the most important while assigning any instruction as register indirect instruction?
- What is the advantage of register indirect addressing mode?
- Which of the following comes under indexed addressing mode?
- Is this a valid statement ? SETB A
- When we add two numbers the destination address must always be
- DAA command adds 6 to the nibble if:
- If SUBB A,R4 is executed, then actually what operation is being applied?
- A valid division instruction always makes:
- In 8 bit signed number operations, OV flag is set to 1 if:
- In unsigned number addition, status of which bit is important?
- Which instructions have no affect on the flags of PSW?
- ANL instruction is used
- CJNE instruction makes
- XRL, ORL, ANL commands have
- What is the clock source for the timers?
- What is the frequency of the clock that is being used as the clock source for the timer?
- What is the function of the TMOD register?
- What is the maximum delay that can be generated with the crystal frequency of 22MHz?
- Auto reload mode is allowed in which mode of the timer?
- Find out the roll over value for the timer in Mode 0, Mode 1 and Mode 2?
- What steps are followed when we need to turn on any timer?
- If Timer 0 is to be used as a counter, then at what particular pin clock pulse need to be applied?
- In the instruction “MOV TH1,#-3”, what is the value that is being loaded in the TH1 register ?
- TF1, TR1, TF0, TR0 bits are of which register?
- Which devices are specifically being used for converting serial to parallel and from parallel to serial respectively?
- What is the difference between UART and USART communication?
- Which of the following best describes the use of framing in asynchronous means of communication?
- Which of the following signal control the flow of data?
- Which of the following is the logic level understood by the micro-controller/micro-processor?
- What is null modem connection?
- Which of the following best states the reason that why baud rate is mentioned in serial communication?
- With what frequency UART operates( where f denoted the crystal frequency )?
- What is the function of SCON register?
- What should be done if we want to double the baud rate?
- When any interrupt is enabled, then where does the pointer moves immediately after this interrupt has occurred?
- What are the contents of the IE register, when the interrupt of the memory location 0x00 is caused?
- After RETI instruction is executed then the pointer will move to which location in the program?
- Which pin of the external hardware is said to exhibit INT0 interrupt?
- Which bit of the IE register is used to enable TxD/RxD interrupt?
- Which of the following combination is the best to enable the external hardware interrupt 0 of the IE register (assuming initially all bits of the IE register are zero)?
- Why normally LJMP instructions are the topmost lines of the ISR?
- Which register is used to make the pulse a level or a edge triggered pulse?
- What is the disadvantage of a level triggered pulse?
- What is the correct order of priority that is set after a controller gets reset?
- How many rows and columns are present in a 16*2 alphanumeric LCD?
- How many data lines are there in a 16*2 alphanumeric LCD?
- Which pin of the LCD is used for adjusting its contrast?
- For writing commands on an LCD, RS bit is
- Which command of an LCD is used to shift the entire display to the right?
- Which command is used to select the 2 lines and 5*7 matrix of an LCD?
- What changes are to be made to send data to an LCD?
- For reading operation from an LCD what changes in the software are introduced?
- Which instruction is used to select the first row first column of an LCD?
- The RS pin is an input or output for a controller?
- Which of the following steps detects the key in a 4*4 keyboard matrix about the key that is being pressed?
- What is described by this command: CJNE A,#00001111b, ROW1
- To detect that in which column, the key is placed?
- In reading the columns of a matrix, if no key is pressed we should get all in binary notation
- If we need to operate a key of a keyboard in an interrupt mode, then it will generate what kind of interrupt?
- To identify that which key is being pressed, we need to:
- Key press detection and Key identification are:
- Why two pins for ground are available in ADC0804?
- When is the function of the WR pin?
- State which of the following statements are false?
- While programming the ADC0804 IC what steps are followed?
- Step size is selected by which two bits?
- What is the difference between ADC0804 and MAX1112?
- Which of the following statements are true about DAC0808 ?
- 8 input DAC has
- INTR, WR signal are an input/output signal pin ?
- What is the function of the SCLK pin in MAX1112 ?
- A thermistor is a:
- What is the difference between LM 34 and LM 35 sensors?
- Transducers produce output voltage in the form of?
- What is signal conditioning?
- What steps have to be followed for interfacing a sensor to a micro controller 8051?
- LM35 has how many pins?
- Why Vref is set of ADC0848 to 2.56 V if analog input is connected to the LM35?
- What is the function of 8255 chip?
- Which pins of a micro controller are directly connected with 8255?
- Find the control word for PA= out, PB= in, PCL=out, PCH=out (Mode0)?
- Which pins are used to select the ports and the control register?
- What is the value of the control register when RESET button is set to zero?
- Why MOVX instruction is being used to access the ports of the 8255?
- What is correct about the BSR mode from below?
- How many pins of the 8255 can be used as the I/O ports?
- DS12887 is a
- What is the RAM space that a DS12887 have?
- How many bytes of the ROM are there for the general purpose applications?
- Which bits of the Register A are used for turning on the oscillator?
- Which out of the following is correct about the SQW pin?
- What is correct about the UIP pin of the register A?
- What is the byte address where time, calendar, alarm address locations etc are kept?
- Are the RAM locations of the DS12887 non volatile?
- Name the read only registers are present in the DS12887?
- What is the supply that a DS12887 consumes even when the power is switched off?
- What is the principle on which electromagnetic relays operate?
- What are DPDT relays?
- Why do we need a ULN2803 in driving a relay?
- Why are solid relays advantageous over electromagnetic relays?
- What are optoisolators?
- How can we control the speed of a stepper motor?
- Which of the following can be a unit for torque?
- The RPM rating given for the DC motor is for?
- PWM allows the control of a DC motor with the same phase, but with different amplitude phases?
- How can the direction of the DC motor be changed?
- Everything compatible with PHP on client side is also compatible with
Computer
PIC (Programmable Integrated Circuits)
(c).the RxD of one is the TxD for the other
need an explanation for this answer? contact us directly to get an explanation for this answer