How is FOSC calculated?
Fosc = your oscillator frequency (for example, 16 MHz). Tosc = 1/Fosc = the period of your oscillator (for example, 62.5 ns in the case of Fosc = 16 MHz).
What is the formula to calculate the count for the timer?
The clock frequency is divided by 12 and used by the timer unit. Thus if a 11.0592MHz external crystal is used, the timer uses a frequency of 921KHz. Thus timer increments every (1/921Khz) = 1.085μ seconds. The C/Ṫ = 0 bit of TMOD register selects operation of Timer/counter unit as timer.
How do you calculate timer prescaler?
PIC Timer 0 : Calculation example Selecting a prescaler ratio of 1:128 gives the following interrupt period (with Fosc/4 or 4MHz/4 = 1MHz) and using the maximum overflow from Timer 0. This is the period of time for each count in Timer 0 i.e. This is the number of counts required after which the interrupt is generated.
What is Tosc in microcontroller?
Tosc is the internal oscillator. Tosc is derived from the external or internal frequency generating device + PLL/dividers. Crystal = 16MHz. PLL = 4X. FOSC = 16MHz x 4 = 64MHz.
What is a clock prescaler?
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.
How high can an 8-bit timer count?
255
8-bit Timers can only count up to 255. Be sure to select a prescalar such that your OCR value will fit in 8-bits.
How do you calculate stopwatch time?
Look at the two smaller numbers after the second. Those numbers move much faster because they are the “hundredths of seconds” used. Combine the number for your full time used. For instance 11:14:01 would be 11 minutes, 14 seconds and 01 hundredths of a second.
What is clock prescaler?
How do you calculate timer interrupt time?
Run the timer at a multiple of your target frequency (10x is easy) Count the number of times the interrupt triggers. When the interrupt has triggered 10 times (if using a 10x faster timer) then reset the count to 0 and trigger your real ISR code.
What is FOSC in microcontroller?
The oscillator configuration register is used for adjusting the clock of the microcontroller. Besides the internal RC oscillator, it is possible to use an external crystal resonator as a source of the clock.
What is prescaler and Postscaler?
A prescaler is an electronic circuit used to reduce a high frequency electrical signal to a low frequency by integer division. Postscaler: A circuit that slows the rate of the interrupt generation(or WDT reset)from a counter/timer by dividing it down.