Timers And Counters In Microcontroller

They can be used as timers or as event counters.

Timers and counters in microcontroller.

The at89s8253 has three timers counters marked t0 t1 and t2. The 8052 has these two plus one more. Both timers are 16 bits wide. That s far from the 1 000 000 ticks per second that the standard avr microcontroller provides.

All three can be configured to operate either as timers or event counters. Every microcontroller has a clock oscillator say in arduino uno it is 16mhz. Timer 0 and timer 1. Thus one can think of it as.

It counts the cycle of the peripheral clock or an externally supplied clock. Timers t0 and t1 completely fall under the 8051 standard. The 16 bit register of timer 0 is accessed as low and high byte. The timer and counter functions in the microcontroller simply count in sync with the microcontroller clock.

Timer mode control tmod. The 8051 has two timers timer 0 and timer 1. That is a far cry from the 1 000 000 ticks per second that the standard avr microcontroller provides. The timer and counter functions in the microcontroller count in sync with the microcontroller clock.

The figure below shows the prescaler and input selector configuration for a timer counter control registered as used in most avr microcontrollers. However the counter can only count up to either 256 8 bit counter or 65535 16 bit counter. They can be used either as timers or as 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.

Counters and timers in 8051 microcontroller contain two special function registers. Tmod is an 8 bit register used for selecting timer or counter and mode of timers. A timer uses counter which counts at certain speed depending upon the clock frequency. So timer counter is a software designed to count the time interval between events.

In arduino uno it takes 1 16000000 seconds or 62nano seconds to make a single count. In the timer mode the register is incremented after every machine cycle. Higher the clock frequency higher will be the processing speed. The 8051 has two timers.

Lower 4 bits are used for control operation of timer. 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. Tmod timer mode register and tcon timer control register which are used for activating and configuring timers and counters. The timers and counters in 8051 microcontroller has two 16 bit timer counter registers.

Both timer 0 and timer 1 are 16 bit wide.