What is the difference between 430 timer capture and compare?

ljk926

What is the difference between 430 timer capture and compare? [Copy link]

What is the difference between 430 timer capture and compare?

wstt

Capture simply means capturing the count value at the time of an event. For example, when measuring the period of a square wave, the count values corresponding to the two rising edges will be captured. Comparison is to compare the value of the counter with the value of the comparison register, which is generally used for PWM output.

ljk926

Can it be understood like this: Capture is when the event occurs (such as a jump), and then the count value at the time of the event is recorded. Compare is to set the value in the register first, and then compare the value of the counter with the value in the register, similar to the initial value setting of the timer of the 51 microcontroller?

huo_hu

Yes, absolutely correct.

ljk926

Then, do we need to subtract the two jump values recorded in the capture by software to get the pulse width of the test?

huo_hu

Counting is a periodic cycle. When it reaches a certain value, it will be 0 (such as one-way). Therefore, the result of simple subtraction is the signed value of the difference. Assume that T1 comes first and T2 comes later if (T2>T1) xxx=T2-T1; else xxx=T2+period-T1;

ljk926

Will it be like this: the pulse width is relatively long, first the T1 counter cycles twice and then T2.

ljk926

How to determine how many times the counter has cycled

huo_hu

It is possible. The maximum count value is 65535. The 72 MHz main frequency is no more than 1ms. If it is not large enough, period = count * 65536 will do. Count is the count when overflow occurs.

ljk926

Oh, that makes sense.

蓦然回首；

Learned

李小川希比

Learned

Sisyphus--

I learned something. Thanks.

zhangxiajoa

Top post, well said :)