Arduino Timer Calculator

Select Timer0 Mode: Normal Mode CTC Mode Fast PWM Mode Phase Correct PWM Mode

Normal Mode

Inputs CPU Freq. (F_osc) Hz KHz MHz Time Delay (T_d) us ms Pre-Scalar (N) clk (No Prescalar) clk/8 clk/64 clk/256 clk/1024 Results TCNT0 (C) Timer Period (T_CPU) Clocks Reqd. (N_c)

About Arduino Timer 0 Calculator

The Normal Mode calculator helps you calculate the timer/counter 0 count value (C) to load into the TCNT0 register for a given CPU frequency and required time delay. It also calculates the CPU time period and number of clock ticks required. Suitable for ATmega328P based boards such as Arduino Uno and Nano.

Equations Used

\(C=256-\frac{F_{CPU}}{N F_{d}}\)   where N is the pre-scalar value
\(F_d=\frac{1}{T_d}\)   where \(T_d\) is the required time delay
\(T_{CPU}=N\times\frac{1}{F_{CPU}}\)
\(N_c=\frac{T_d}{T_{CPU}}\)

CTC Mode

Inputs CPU Freq. (F_osc) Hz KHz MHz Wave Freq. (F_w) Hz KHz MHz Pre-Scalar (N) clk (No Prescalar) clk/8 clk/64 clk/256 clk/1024 Results OCR0 Timer Freq. (F_d) Timer Delay (T_d)

About Arduino Timer 0 CTC Mode Calculator

The CTC Mode calculator helps you calculate the timer/counter 0 count value (C) to load into the OCR0 register for a given CPU frequency and desired output wave frequency.

Equations Used

\(C=\frac{F_{osc}}{2 N F_{w}}-1\)
where F_osc is the CPU frequency, F_w is the output square wave frequency and N is the pre-scalar value.

Fast PWM Mode

Non-Inverted Mode CPU Freq. (F_osc) Hz KHz MHz Duty Cycle % Pre-Scalar (N) clk (No Prescalar) clk/8 clk/64 clk/256 clk/1024 Results OCR0 Wave Freq. (F_w) Wave Period (T_w)

Inverted Mode

CPU Freq. (F_osc) Hz KHz MHz Duty Cycle % Pre-Scalar (N) clk (No Prescalar) clk/8 clk/64 clk/256 clk/1024 Results OCR0 Wave Freq. (F_w) Wave Period (T_w)

About Arduino Timer 0 Fast PWM Mode Calculator

The Fast PWM calculator calculates the wave frequency and OCR0 register value for both non-inverted and inverted modes.

Equations Used

\(F_{w}=\frac{F_{osc}}{256N}\)
\(OCR0_{non\text{-}inv} = \frac{256D}{100} - 1\)
\(OCR0_{inv} = 255 - \frac{256D}{100}\)

Phase Correct PWM Mode

Non-Inverted Mode CPU Freq. (F_osc) Hz KHz MHz Duty Cycle % Pre-Scalar (N) clk (No Prescalar) clk/8 clk/64 clk/256 clk/1024 Results OCR0 Wave Freq. (F_w) Wave Period (T_w)

Inverted Mode

CPU Freq. (F_osc) Hz KHz MHz Duty Cycle % Pre-Scalar (N) clk (No Prescalar) clk/8 clk/64 clk/256 clk/1024 Results OCR0 Wave Freq. (F_w) Wave Period (T_w)

About Arduino Timer 0 Phase Correct PWM Mode Calculator

The Phase Correct PWM calculator calculates the wave frequency and OCR0 register value for both non-inverted and inverted modes.

Equations Used

\(F_{w}=\frac{F_{osc}}{510N}\)
\(OCR0_{non\text{-}inv} = \frac{255D}{100}\)
\(OCR0_{inv} = 255 - \frac{255D}{100}\)