Realizing Soft Timer Using Timer Interrupt of Single Chip Microcomputer-EEWORLD

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The following code has been tested and used in the project and can be used with confidence

Author : I am from Qi

#include "reg52.h"

#include "Intrins.h"

#include "TypeDef.h"

#include "CPUPin_Def.h"

#include "VarDef.h"

#define TIME_BASE_2MS 2

#define TIME_BASE_500MS 250

#define TIME_BASE_10MS 5

#define F_OSC 110592 //Define this to calculate the value of TH0 TL0 according to the 11.0592MHZ crystal oscillator by default. Mode 1 16-bit timer

//Note that this writing method is only useful when the crystal oscillator is doubled.

//Because the 51 MCU hardware does not support floating point operations, 12/11.0592 = 1 is rounded down to the same crystal value as 11.0592.

// If floating-point operations are supported, there will be special hardware floating-point operation instructions inside the chip. This writing method is not acceptable and the type must be forced to convert

//For example, (double)12/(double)11.0592 needs to be converted to a floating point number.

// Currently, there is hardware support for floating point and software floating point , which means that software can also implement floating point operations. For example, when the compiler sees special code, it will turn to

//A special function to handle. 51 STM32 microcontrollers currently do not seem to support hardware floating point numbers

void Timer0() interrupt 1 using 1

{

//Using static variables, this will only be executed once, no matter how many interrupts occur because it is a static variable

//But it cannot be written as

//If the actual crystal oscillator is 12MHZ, change it to F_OSC / 120000 because TH0 TL0 is calculated according to 11.0592

static uchar TimeBase2ms = TIME_BASE_2MS * (F_OSC / 110592);

//If the crystal oscillator is 11.0592 , then the value is 1. If it is 12.00MHZ , then the value is 1.085xxxx. If the crystal oscillator runs fast, the value should be larger.

//Just change the F_OSC macro directly. No need to change other

static uchar idata TimeBase500ms = TIME_BASE_500MS * (F_OSC / 110592);

static uchar TimeBase10ms = TIME_BASE_10MS *(F_OSC / 110592);

static unsigned char CountSignalDelay = 0;

//The above will only execute once static definition declaration initialization

uchar i;

TH0=0xfc; // Total timing is 1000 microseconds, it takes 12 cycles to enter the interrupt, so the actual timing is 1000 - 12 * 12 / F

TL0=0x72 ;

//The tool calculates here that it should be FC 66 FC72-FC66 = 12

//Let the loaded number use 12 fewer cycles to enter the interrupt because entering the interrupt requires 12 cycles plus exactly 1ms

_push_( SCONF ) ;

if( --TimeBase2ms == 0 ){

TimeBase2ms = TIME_BASE_2MS * (F_OSC / 110592);

//0--3 is a timer with a time base of 2 milliseconds

for( i = 0; i < 4; i++ )

{

if( TimerNo[ i ] != 0 ){

if( --( TimerNo[ i ] ) == 0 ){//Time is up

fTimer |= 0x01 << i; //set to timeout

}

if( --TimeBase10ms == 0 )

{

TimeBase10ms = TIME_BASE_10MS * ( F_OSC / 110592 );

ScanCopierSignal() ;//Function that is called once every 10 milliseconds

}

if( --TimeBase500ms == 0 )

{

TimeBase500ms = TIME_BASE_500MS * ( F_OSC / 110592 );

//Processing timer with 500ms as time base

for( i = 4; i < 8; i++ )

{

if( TimerNo[ i ] != 0 ){

if( -- ( TimerNo[ i ] ) == 0 ) {

fTimer |= 0x01 << i;

}

_pop_(SCONF);

}

Keywords：MCU Reference address：Realizing Soft Timer Using Timer Interrupt of Single Chip Microcomputer

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