The Data Pointer (DPTR) is the 8051s only user-accessable 16-bit (2-byte) register. The Accumulator, “R” registers, and “B” register are all 1-byte values. DPTR, as the name suggests, is used to point to data. It is used by a number of commands which allow the 8051 to access external memory.

Then, What is Pcon?

PCON. Acronym. Definition. PCON. Power Control (Intel 8051 Microcontroller register)

Considering this, Is SCON bit addressable? While all I/O ports are bitaddressable, that is not the case with registers, as seen from Figure 5-1. Only registers A, B, PSW, IP, IE, ACC, SCON, and TCON are bitaddressable. Of the bitaddressable registers, we will concentrate on the familiar registers A, B, and PSW.

22 Related Questions and Answers Found ๐Ÿ’ฌ


What is the use of Pcon register?

The PCON or Power Control register, as the name suggests is used to control the 8051 Microcontroller’s Power Modes and is located at 87H of the SFR Memory Space. Using two bits in the PCON Register, the microcontroller can be set to Idle Mode and Power Down Mode.

What is DPH and DPL in 8051?

In 8051 assembly code, this address pointer is called DPTR. Because the 8051 is an 8-bit microcontroller, the 16-bit data pointer is controlled by two byte-wide registers, DPH (data pointer high-byte) and DPL (data pointer low-byte).

What is PSW in microcontroller?

PSW (program status word) register

The program status word (PSW) register is an 8-bit register. It is also referred to as the flag register. Although the PSW register is 8 bits wide, only 6 bits of it are used by the 8051. The two unused bits are user-definable flags.

What is Sbuf?

SBUF Register โ€ข The special function register SBUF is physically two registers. ? One is, write-only and is used to hold data to be transmitted out of the 8051 via TXD.

How many interrupts are there in 8051?

5 interrupt

How many registers are there in 8051 microcontroller?


What is PSW in 8051 microcontroller?

The Program Status Word (PSW) contains status bits that reflect the current CPU state. The 8051 variants provide one special function register called PSW with this status information. The 251 provides two additional status flags, Z and N, that are available in a second special function register called PSW1.

What is push and pop Instruction in 8051?

Q: Why is such an oddball crystal frequency of 11.0592 MHz used so often for 8051 designs. A1: 11.0592 MHz crystals are often used because it can be divided to give you exact clock rates for most of the common baud rates for the UART, especially for the higher speeds (9600, 19200).

What do you mean by microcontroller?

A microcontroller is a computer present in a single integrated circuit which is dedicated to perform one task and execute one specific application. It contains memory, programmable input/output peripherals as well a processor.

What is electronic timer?

Timer is a circuit or an Integrated circuit which produces output like pulse or square wave and it’s on time or off time ( low or high) can be changed according to the requirements. IC 555 provides time delay from few micro seconds to hours and it can be operated in three modes such as Astable, Monostable and Bistable.

What is crystal frequency 8051?

The internal circuitry in the 8051 microcontrollers provides a clock source to the timers which is 1/12th of the frequency of crystal attached to the microcontroller, also called as Machine cycle frequency. For example, suppose we have crystal frequency of 11.0592 MHz then microcontroller will provide 1/12th i.e.

How many types of registers are there?

There are various types of Registers those are used for various purpose. Some Mostly used Registers are Accumulator(AC), Data Register(DR), Address Register(AR), Program Counter(PC), Memory Data Register (MDR), Index Register(IR), Memory Buffer Register(MBR).

What is bit addressable register?

What is the disadvantage of a level triggered pulse?

What is the disadvantage of a level triggered pulse? Explanation: In a level triggered pulse, if the signal does not become high before the last instruction of the ISR, then the same interrupt will be caused again, so monitoring of pulse is required for a level triggered pulse.

What is SFR in 8051?

Special Function Registers (SFR)

Special function registers are upper RAM memory in the 8051 microcontroller. These registers contain all peripheral related registers like P0, P1, P2, P3, timers or counters, serial port and interrupts-related registers.

What is the function of program counter?

A program counter is a register in a computer processor that contains the address (location) of the instruction being executed at the current time. As each instruction gets fetched, the program counter increases its stored value by 1.

How many interrupts are there in 8051?


What is accumulator in computer?

In a computer‘s central processing unit (CPU), the accumulator is a register in which intermediate arithmetic and logic results are stored.

What is the difference between microprocessor and microcontroller?

Microprocessor is an IC which has only the CPU inside them i.e. only the processing powers such as Intel’s Pentium 1,2,3,4, core 2 duo, i3, i5 etc. Microcontroller has a CPU, in addition with a fixed amount of RAM, ROM and other peripherals all embedded on a single chip.

What is push and pop Instruction in 8051?

Timers in 8051 microcontroller. The timer is an important application in Embedded systems, it maintains the timing of an operation in sync with a system clock or an external clock. The timer has so many applications such as measure time generating delays, they can also be used for generating baud rates.

What is 16bit timer?

The “Bregister is very similar to the Accumulator in the sense that it may hold an 8-bit (1-byte) value. Aside from the MUL and DIV instructions, the “Bregister is often used as yet another temporary storage register much like a ninth “R” register.

What is a banked register?

Register banking refers to providing multiple copies of a register at the same address. There is a different register bank for each processor mode. The banked registers give rapid context switching for dealing with processor exceptions and privileged operations.

What is a stack pointer in 8051?

As the stack is a section of a RAM, there are registers inside the CPU to point to it. The register used to access the stack is known as the stack pointer register. The stack pointer in the 8051 is 8-bits wide, and it can take a value of 00 to FFH. When the 8051 is initialized, the SP register contains the value 07H.

What is a stack pointer in 8051?

To add a register on to the stack, use PUSH. You can add all the registers at the start of each subroutine in order, do the work in the registers, then POP the original values back, in reverse order. Then Return from subroutine.

What is DJNZ in 8051?

DJNZ. Home ยป Instructions ยป DJNZ. The DJNZ instruction decrements the byte indicated by the first operand and, if the resulting value is not zero, branches to the address specified in the second operand.

How many 16 bit registers are available in 8051?


How many timer is 8051?

two timers

What do you mean by counters describe the different parts of it?

Counter is a digital device and the output of the counter includes a predefined state based on the clock pulse applications. The output of the counter can be used to count the number of pulses. Generally, counters consist of a flip-flop arrangement which can be synchronous counter or asynchronous counter.

What is B register?


How does timer work in microcontroller?

The timer and counter functions in the microcontroller simply count in sync with the microcontroller clock. However, the counter can only count up to either 256 (8-bit counter), or 65535 (16-bit counter). Mainly, timers have a register for control, and a register that holds the count number.

What is difference between timer and counter in 8051?

The “Bregister is very similar to the Accumulator in the sense that it may hold an 8-bit (1-byte) value. Aside from the MUL and DIV instructions, the “Bregister is often used as yet another temporary storage register much like a ninth “R” register.