C51 software accurate delay (us level)-EEWORLD

The C language code is as follows:

/*----------------------------------------------------------------------

Function: Software precise delay

Descripton: One is to use the three single-cycle instructions of C51, assignment, comparison, and decrement, to implement software delay;

Another method is to use the C51 library function _nop_() software to delay a machine cycle.

System crystal frequency: 11.0592MHz

Author: Zhang Kaizhou

Date: 2019-6-19 11:51:55

-----------------------------------------------------------------------*/

#include

#define uchar unsigned char

#define uint unsigned int

void main(){

uint i; // The delay length range can be expanded by changing the data type of i

i = 100; while(i) i--;

Delay length = 10.85 + (i - 1) * 8.68;

Then i = ((delay length - 10.85) / 8.68) + 1;

For example: if the delay is 60us, then i = (60 - 10.85) / 8.68 + 1 = 7;

(When the value of i is rounded up, the delay will be slightly longer than the target duration [2 machine cycles];

(When the value of i is rounded down, the delay will be slightly less than the target duration [2 machine cycles])

_nop_(); // Delay one machine cycle 1.08us

while(1);

}

Keywords：C51 Reference address：C51 software accurate delay (us level)

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