Clock signal for timer Tim3 is 80 MHz. Channel 1 of the timer is configured in input capture counter reset mode (rising edge polarity). The value of TIM3_PSC is 79. The value of Tim3_CCR1 register determined in input capture interrupt handling function is 2000. Determine the period of the incoming signal. Show your work.
To calculate the period of the incoming signal, we first need to determine the frequency of the input signal using the information provided.
The prescaler value (TIM3_PSC) is 79, which means the timer clock frequency is divided by 80 (79+1). So, the effective clock frequency for Timer Tim3 is:
Effective Clock Frequency = Clock Signal / (TIM3_PSC + 1)
Effective Clock Frequency = 80 MHz / (79 + 1)
Effective Clock Frequency = 80 MHz / 80
Effective Clock Frequency = 1 MHz
Next, we can calculate the time taken by the counter to reach the value of Tim3_CCR1.
Time taken = (Tim3_CCR1 + 1) / Effective Clock Frequency
Time taken = (2000 + 1) / 1 MHz
Time taken = 2001 / 1,000,000
Time taken = 0.002001 seconds
Finally, the period of the incoming signal is twice the time taken by the counter to reach the value of Tim3_CCR1, because the timer is in input capture counter reset mode (rising edge polarity), so the timer counts the time it takes for the input signal to rise from 0 to the value in CCR register and then again from that value to the next value.
Period = 2 * Time taken
Period = 2 * 0.002001
Period = 0.004002 seconds
Therefore, the period of the incoming signal is 0.004002 seconds or 4.002 ms.