The specific method is similar to this.

Calculate the number of cycles according to the number of microseconds to be delayed.

This calculation ratio is 5/4 in this example, probably 1.25.

In other words, it takes about 0.8 microseconds to execute a for loop.

In this way, if a delay of 1000 microseconds is required, a cycle of 1000/0.8 is required, that is, 1000*5/4. When the delay value is not a multiple of 4, the calculation will have an error.

The maximum error is 3 cycles, that is, 3*0.8=2.4 microseconds. Generally speaking, such an error should be acceptable.

As for the specific value of this parameter, it depends on the time required to execute a for loop operation, that is, the time to add and judge once.

This should be calculated according to the CPU frequency and can also be measured.