* Question
| What is the operating principle of the input capture function? |
* Answer
| The block diagram of the input capture module is shown in Figure 4.2. It consists of a 16-bit free-running counter register TCNT, a 16-bit channel register TCH, input signal edge detection logic, and interrupt logic.In the timer module of the MC68HC08 family of microcontrollers, each timer has two independent input capture/output compare channels, each of which can be used as both an input capture function and an output compare function.This channel register is the output compare register.The input capture register and the output compare register share the same register in time sharing.
When used as an input capture, the channel register is used as an input capture register, which is a read-only register, and the upper 8 bits and lower 8 bits of the register are read separately.Therefore, when the input capture function is used to measure the input signal, there is a limit on the frequency of the input signal, and signals above this upper limit frequency cannot be accurately measured. |
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