What are the different ways to introduce a delay in 8051 C?

8051 microcontroller has two timers: Timer0 and Timer1.

The last two bits for each timer i.e. M1 and M0 are used to select the timer mode.

For time delay,the timer use the clock source of the crystal frequency of the crystal attached to 8051.

The second special function register is Timer control register.

How timers of 8051 can be used as timer or as an event counter?

Timers can also be used as counters counting events happening outside the 8051. When it is used as a counter, it is a pulse outside of the 8051 that increments TH, TL registers. The C/T bit in the TMOD registers decides the source of the clock for the timer.

How do you create a time delay?

Delay Function to Generate 1 ms Delay

1. NNNN = 1ms/1.085μs ≈ 922.
2. MMMM = 65536-922 = 64614.
3. 64614 in Hexadecimal = FC66h.
4. Load TH with 0xFC and TL with 0x66.

How can you generate the time delay in 8051?

Write up a delay subroutine with delay equal to half the time period of the square wave. Make any port pin high and call the delay subroutine. After the delay subroutine is finished, make the corresponding port pin low and call the delay subroutine gain. After the subroutine is finished , repeat the cycle again.

Which technique is used to provide time delay?

1. LOOP TECHNIQUE. This is very simple software based delay technique. In this method we load a number in a RAM location and decrement it till it becomes Zero.

How do I add a delay in assembly language?

One classic way to make a delay is to use nested decrement loops. Every time the inner loop counts down to 0, then the next decrements, and so on. It’s a bit tedious to adjust the timing, and interrupts will mess with the process, but it works.

What are the types of timer modes in 8051?

In Intel 8051, there are two 16-bit timer registers. These registers are known as Timer0 andTimer1. The timer registers can be used in two modes. These modes areTimer mode and the Counter mode.

How does 8051 timer work?

8051 timers have both software and hardware controls. The start and stop of a timer is controlled by software using the instruction SETB TR1 and CLR TR1 for timer 1, and SETB TR0 and CLR TR0 for timer 0. The SETB instruction is used to start it and it is stopped by the CLR instruction.

What is delay in embedded system?

In Embedded System Delay is used to halt the system to execute previous instructions. Serial. println(“LED ON”); delay(100); delay is used over here to print the string on serial monitor for 100ms then it will start executing next instruction.

Which register you will use to generate the delay?

Using 8-bit register as counter: Counter is another approach to generate a time delay.

How can we provide the time delay using a register pair?

time delay required and then the register is decremented until it reaches zero by setting up a loop with conditional jump instruction. Write a Program to count continuously from FFH to 00H using register C with delay count 8CH between each count and display the number at one of the output ports.

How do you change the delay generated with the help of software loop?

The idea is very simple, run a subroutine with delay equal to half the time period of the square wave, complement any port pin after the delay routine is finished, repeat the delay subroutine again, complement the same port pin again and repeat the cycle again and again over time.

How to generate precise delay using 8051 timers?

Steps for generating precise Delay using 8051 Timers. In order to produce time delay accurately, Divide the time delay with timer clock period. NNNN=time delay/1.085μs. Subtract the resultant value from 65536. MMMM=65536-NNNN. Convert the difference value to the hexa decimal form. MMMMd = XXYYh. Load this value to the timer register. TH=XXh. TL=YYh

Are loops suitable for 8051 series microcontrollers?

Loops are only suitable if you want an arbitrary delay in your program and not a proper fixed time delay. In order to generate proper delays you have to use the internal timers of 8051 (89c51,89c52) microcontroller. 8051 series microcontrollers have two build in timers (Timer-0 & Timer-1).

How can I generate square waves with the 8051 timer?

Square waves of any frequency (limited by the controller specifications) can be generated using the 8051 timer. The technique is very simple. Write up a delay subroutine with delay equal to half the time period of the square wave. Make any port pin high and call the delay subroutine.

How to calculate the time delay of 16 bit timer?

Firstly divide the desired time delay value (10 ms) by the timer clock period. Subtract the value of N from the maximum number of counts possible for 16 bit timer i.e. 2^16 = 65536. Convert this value to hexadecimal and write in TH and TL registers. Take an example of creating a delay of 10ms using timers of 8051 microcontroller.