Use this embedded-systems calculation to configure or check a timer, serial bus, ADC, PWM, buffer, power mode, flash budget, or watchdog from known clock and device parameters.

Clock Hertz (Hz)

Required number input.

Prescaler

Required integer input.

Reload Value

Required integer input.

Nominal watchdog timeout for an inclusive reload counter. Prescaler is the effective watchdog-clock divisor; verify the device's register encoding and oscillator tolerance. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Timeout Seconds (s)

The resulting timeout seconds returned as a number.

• Register widths, clock trees, prescalers, oscillator tolerance, interrupt latency, peripheral modes, voltage references, quantization, sleep states, endurance conditions, and silicon errata are device-specific.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Confirm equations against the exact datasheet and reference manual, derive register values with integer rounding visible, and verify timing or voltage on hardware.

• Timer Overflow Period

  Overflow interval for a free-running N-bit timer with a zero-based counter. Prescaler is the effective clock divisor, not necessarily the raw register value.

• PWM Frequency

  Edge-aligned PWM frequency with an inclusive auto-reload value and effective prescaler divisor. On timers whose PSC register divides by PSC+1, enter PSC+1.

• Timer Compare Frequency

  Compare-event rate for an up-counter that resets after an inclusive compare value. Enter the effective prescaler divisor; devices with a PSC register may divide by PSC+1.