What is a prescaler in timer?

What is a prescaler in timer?

A prescaler is an electronic counting circuit used to reduce a high frequency electrical signal to a lower frequency by integer division. The purpose of the prescaler is to allow the timer to be clocked at the rate a user desires.

What are the two types of AVR timer mode?

In AVR, timers are of two types: 8-bit and 16-bit timers. In an 8-bit timer, the register used is 8-bit wide whereas in 16-bit timer, the register width is of 16 bits. This means that the 8-bit timer is capable of counting 2^8=256 steps from 0 to 255 as demonstrated below.

Which timer has both options of prescaler and Postscaler?

Timer2 is an 8-bit timer with a prescaler, a postscaler, and a period register. Using the prescaler and postscaler at their maximum settings, the overflow time is the same as a 16-bit timer.

What is the difference between prescaler and timer timer?

Timers. When using the prescaler you can achieve greater timer values, while precision goes down. The prescaler can be set to 8, 64, 256 or 1024 compared to the system clock. An AVR at 8 MHz and a timer prescaler can count (when using a 16-bit timer) (0xFFFF + 1) * 1024 clock cycles = 67108864 clock cycles which is 8.388608 seconds.

How many clock cycles does an AVR have?

An AVR at 8 MHz and a timer prescaler can count (when using a 16-bit timer) (0xFFFF + 1) * 1024 clock cycles = 67108864 clock cycles which is 8.388608 seconds.

What is the advantage of using a prescaler?

When using the prescaler you can achieve greater timer values, while precision goes down. The prescaler can be set to 8, 64, 256 or 1024 compared to the system clock. An AVR at 8 MHz and a timer prescaler can count (when using a 16-bit timer) (0xFFFF + 1) * 1024 clock cycles = 67108864 clock cycles which is 8.388608 seconds.

How accurate is a 16 bit timer with a 1024 prescale?

But if you set the timer to /1024 prescale now your accuracy is just 62.5ns * 1024 = 64us so you can only change the timer in steps of 64us but the counting range is much extended. At /1 a 16 bit timer can only count to 65536 * 62.5ns which is 0.004 of a second.