Timers And Counters In Microcontroller

A timer uses counter which counts at certain speed depending upon the clock frequency.

Timers and counters in microcontroller.

That is a far cry from the 1 000 000 ticks per second that the standard avr microcontroller provides. In the timer mode the register is incremented after every machine cycle. Timer mode control tmod. The timers and counters in 8051 microcontroller has two 16 bit timer counter registers.

Lower 4 bits are used for control operation of timer. However the counter only counts up to to either 256 8 bit counter or 65535 16 bit counter. The figure below shows the prescaler and input selector configuration for a timer counter control registered as used in most avr microcontrollers. 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.

Tmod is an 8 bit register used for selecting timer or counter and mode of timers. Tmod timer mode register and tcon timer control register which are used for activating and configuring timers and counters. They can be used as timers or as event counters. This is responsible for speed.

Counters and timers in 8051 microcontroller contain two special function registers. The timer and counter functions in the microcontroller simply count in sync with the microcontroller clock. Both timers are 16 bits wide. The 8051 has two timers timer 0 and timer 1.

That s far from the 1 000 000 ticks per second that the standard avr microcontroller provides. The timer counter control register tccrx associated with the timer contains the counter select bits csx2 csx1 csx0 that control which input is used with a specific counter. Both timer 0 and timer 1 are 16 bit wide. Thus one can think of it as.

So timer counter is a software designed to count the time interval between events. The 16 bit register of timer 0 is accessed as low and high byte. It counts the cycle of the peripheral clock or an externally supplied clock. All three can be configured to operate either as timers or event counters.

Higher the clock frequency higher will be the processing speed. They can be used either as timers or as counters. The at89s8253 has three timers counters marked t0 t1 and t2. However the counter can only count up to either 256 8 bit counter or 65535 16 bit counter.

Since the 8051 follows an 8 bit architecture each 16 bit is accessed as two separate registers of low byte and high byte. Timer 0 and timer 1. Timers t0 and t1 completely fall under the 8051 standard. The 8051 has two timers.

Every microcontroller has a clock oscillator say in arduino uno it is 16mhz.