One minute delay generation with 8051(89c51,89c52) microcontroller internal timers for led blinking

Giving a proper delay like 1-Second OR 1-Minute is possible only by using internal timers of 8051(89c51,89c52) microcontroller. The 8051 series microcontrollers have two build in 16-bit timers Timer 0 & Timer 1, Some also have an extra timer Timer 3 . You can use them to generate delays, baud rate for UART for serial Communication OR trigger an event source to execute an interrupt when ever a particular condition is meet. I strongly recommend you to take a simple tutorial on internal timer registers of 8051(89c51,89c52) microcontrollers and registers associated with them.

The Registers Associated with Timers of 89c51 Microcontroller.

If you don’t know the internal registers dedicated for timer’s you will be unable to understand the tutorial and code below. Generating delays of specific time is not easy using internal timers of 8051 microcontrollers. It requires an extensive knowledge to properly generate delays.

The Project/tutorial is simple just blinking an led after every 1 minute. I calculated the delay for 2 ms and loaded the Calculated values in TH and TL register. To calculate the values go through the tutorial link given above. Now if i run 2 ms delay for 500 times it will generate 1-Second Delay. Running this 1-Second Delay for 60 Times gives me 1-Minute Delay.

Delay Generation using Timers of 8051(89c51) Microcontroller

8051 microcontroller 1 second delay circuit diagram

The circuit diagram is pretty straight forward. Led is connected to Port-1 Pin#0. Making this pin high and low will make led blink. Main function is easy to understand. The delay() function is generating 1-Minute delay for us. At the top is for loop, Which is running 60 times. To generate 1-Minute delay, Loop is running 60 Times generating 60 seconds. Then while loop is running 500 times to generate 1-Second delay.

The above tutorial is very important to understand the delay function. I calculated values of TH and TL register for 2ms delay and run them for 1ms(500 Times). The code is generating exactly 1ms delay.

Port-1 Pn#0 is connected with led -(Negative) leg. Apply 5 volts to +(Positive) leg of led. Connect Oscillator(11.0592MHz) with PIN# 18 & 19 (XTAL0, XTAL1) of 89c51 Microcontroller. Apply 5 volts to Pin#40 & 31 of 8051(89c51).Ground Pin# 20.

Led with 8051(89c51) Microcontroller

Please take the tutorial if you are not familiar with the internal timer registers of 8051(89c51,89c52) microcontroller. The tutorial will help you in understanding the code below.

8051 TIMER REGISTERS AND THEIR WORKING

I made digital clock with 89c51 microcontroller by utilizing the above time delay technique. You can see the post. Each project code and circuit diagram is free.

Download the Project files, code(c & Hex) compiled in c using keil U-vision4. If you have any questions regarding the post Plz write your queries below.

One Minute Delay Generation with 89c51 Microcontroller