Timer can be used as a counter as well as for timing operation that depends on the source of clock pulses to counters. The 8051 has two counters timers which can be used either as timer to generate a time delay or as counter to count events happening outside the microcontroller. Timer and counter in 8051 microcontroller slideshare. What is the width of the program counter in an 8051 microcontroller.
There is literally a thin line between timer and counter. What is the reason as i am not getting call to return of delay function. The distinction actually comes from how this result is used. A timer module for an 8051 microcontroller is designed from the ground up. For example, a clock pulse with a duty cycle of 500ms will count 1s per cycle. Both timers consist of 16bit register in which the lower byte is stored in tl and the higher byte is stored in th.
As were a counter only records an overall length of time. Thus this timer is programmable between 1 microsecond and 256 microseconds. In this article, we focus on timerscounters of the 8051 micro controller. If the timer is initialized to a value of 252, for example, it will count just 4 microseconds before overflow. Mode 2 can be thought of as a countdown timer or counter. Timer counter counts up it is incremented by microcontroller timer. This idea can be extended into much smaller or larger time scales. It is used to count the events happening outside the microcontroller.
Embedded systems timercounter a timer is a specialized type of clock which is used to measure time intervals. For example, we could count the number of times that a pushbutton is pressed by connecting it to the input of a timer counter module see figure 11. What is the difference between the dn and en outputs of a timer or counter in a plc. Timer counter special function registerstmod m0 and m1 bits are used to set timer mode the same for timer0 and timer1 8051 delivers 4 timer modes. Since the 8051 follows an 8bit architecture, each 16 bit is accessed as two separate registers of lowbyte and highbyte. What is the difference between timer and counter in. The difference between a timer and a counter is that a timer can be set to record different time intervals. Timer can be used as a counter as well as for timing. Before programming we should know the timer registers. What is the difference between timer and counter in the 8051. Electronics projects, electronic circuit and embedded systems resources with working explanation of diagrams, tutorials and calculation. Many microcontroller application requires the counting of external events such as frequency, time delay.
Gadgetronicx electronics projects, circuit and embedded. M1 m0 mode description 0 0 mode 0 bit timer 0 1 mode 1 16bit timer 1 0 mode 2 8bit auto reload 1 1 mode 3 split timer mode april 10 9. Introduction to timer counter peripherals so what is the difference between a counter and a timer. There are two 16bit timers and counters in 8051 microcontroller. What is the difference between integrated circuit and microcontroller. A counter can be set up to count time intervals, such as the clock pulses. In this article, we focus on timers counters of the 8051 micro controller.
What is the difference between timer and counter in microcontrollers. Both can do the same work but they both are used in different scenarios. Tmod is an 8bit register used to set timer mode of timer0 and timer1. View notes 8051 timer counter from comp 2008 at caltech. Video lecture on timers and counters in 8051 microcontroller from introduction to 8051 microcontroller chapter of 8051 microcontroller and its applications for all. The third timer has some new operation modes not available with the 8051.