y=expf(x); Why does "x" change and affect "LPC_TMR16B1->TC"?

[Wei_Lang]

//  y=expf(x); Why does "x" change and affect "LPC_TMR16B1->TC"?

#include <LPC112x.h>

#include "wdt.h"

#include "math.h"

volatile uint32_t msTicks;/* counts 10ms timeTicks */

volatile uint32_t jishuzhi=0;/* 计数值 */

int32_t clk[12]={0};

int32_t mV0,mV50,mV100,t14,t750;

float c_o2,vo2,tt;

float vo2b,k82,k0,k_299,vt,outmA;

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

  SysTick_Handler

#define __SYSTEM_CLOCK  (__MAIN_CLOCK / SYSAHBCLKDIV_Val)

__XTAL_CLK * 4  (__MAIN_CLOCK / 1)

#define __MAIN_CLOCK    (__SYS_PLLCLKOUT)

#define __SYS_PLLCLKOUT (__SYS_PLLCLKIN * ((SYSPLLCTRL_Val & 0x01F) + 1))

(__SYS_PLLCLKIN * (3+1))

#define __SYS_PLLCLKIN  (__SYS_OSC_CLK)

#define __SYS_OSC_CLK   (   __XTAL_CLK)=11059200

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

void SysTick_Handler(void) {

  msTicks++;

}

/*****************************************************

**函数名称：TIMER16_1_IRQHandler()

**函数功能：定时/计数器1中断服务程序

******************************************************/

void TIMER16_1_IRQHandler(void)//UART1

{

LPC_TMR16B1->IR=(1UL << 5);

}

void CT16B1_Initialize(void)

{

LPC_IOCON->PIO3_5 = 0xD1;//PIO3_5 CT16B1_CAP1

LPC_SYSCON->SYSAHBCLKCTRL |= (1UL << 8);/* enable clock for CT16B1 */

LPC_TMR16B1->IR=(1UL << 5);

LPC_TMR16B1->TCR=3;//Enable and Reset

LPC_TMR16B1->PR=0;//4x11059200不分频

LPC_TMR16B1->CCR = 0;//((1UL << 3) | (1UL << 5));//Interrupt on CT16Bn_CAP1 event

LPC_TMR16B1->CTCR=5;//计数器,上升沿,CT16B1_CAP1

LPC_TMR16B1->TCR=1;//Enable and Go

NVIC_EnableIRQ(17);

}

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

  delays number of tick Systicks (1-250 ms)

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

void Delay (uint32_t dlyTicks) {

  uint32_t curTicks;

  curTicks = msTicks;

  while ((msTicks - curTicks) < dlyTicks) { __NOP(); }

}

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

  delays number of tick Systicks (3276800约1.195s)

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

void Delay1 (uint32_t dlyTicks) {

  for(;dlyTicks > 0;dlyTicks--) { __NOP(); }

}

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

  MAIN function

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

int main (void) {

__disable_irq();

k0=0.0;

  SystemCoreClockUpdate();                      /* Get Core Clock Frequency   */

msTicks=0;

  if (SysTick_Config(SystemCoreClock / 800)) {  /* SysTick 1/800 s interrupts */

    while (1) __NOP();                          /* Capture error               */

  }

Delay1 (400);

Wdt_Initialize();

CT16B1_Initialize();

msTicks=0;

__enable_irq();

  while(1) {

if(msTicks>=200) {

msTicks=0;

clk[0]=LPC_TMR16B1->TC;//PIO3_5 CT16B1_CAP1

LPC_TMR16B1->TCR=3;

Delay1 (4);

LPC_TMR16B1->TCR=1;

c_o2=expf(k0);

if((k0>=-6.0 && k0<-5.0) || (k0>=2.5 && k0<3.5)) k0+=0.1;

else if(k0==-5.0) k0=2.5;

else if(k0==3.5) k0=-6.0;

else k0=-6.0;

Wdt_Feed();

}

}

}

[Harry_Zhang]

Hi @Wei_Lang 

Do you mean that the variation of LPC_TMR16B1->TC is determined by the number of rising edges of the external input to PIO3_5 pin?

BR

Harry

[Wei_Lang]

Thank you for your reply！

1. PIO3_5 CT16B1_CAP1

void CT16B1_Initialize(void)
{
LPC_IOCON->PIO3_5 = 0xD1;//PIO3_5 CT16B1_CAP1
LPC_SYSCON->SYSAHBCLKCTRL |= (1UL << 8);/* enable clock for CT16B1 */
LPC_TMR16B1->IR=(1UL << 5);
LPC_TMR16B1->TCR=3;//Enable and Reset
LPC_TMR16B1->PR=0;//4x11059200不分频
LPC_TMR16B1->CCR = 0;//((1UL << 3) | (1UL << 5));//Interrupt on CT16Bn_CAP1 event
LPC_TMR16B1->CTCR=5;//计数器,上升沿,CT16B1_CAP1
LPC_TMR16B1->TCR=1;//Enable and Go
NVIC_EnableIRQ(17);
}

//It has the problem

2. PIO3_5 GPIO3_5  EINT3

void EINT3_Initialize()

{

LPC_IOCON->PIO3_5 = 0xD0;//GPIO3_5 Pull-up resistor enabled

LPC_SYSCON->SYSAHBCLKCTRL |= (1UL << 6);     /* enable clock for GPIO      */

LPC_GPIO3->DIR  &= ~(1UL << 5);

LPC_GPIO3->IS   &= ~(1UL << 5);

LPC_GPIO3->IBE  &=~(1UL << 5);

LPC_GPIO3->IEV  &= ~(1UL << 5);

LPC_GPIO3->IE   |=  (1UL << 5);

LPC_GPIO3->IC   |=  (1UL << 5);

NVIC_EnableIRQ(28);

// NVIC_SetPriority (19, 2);  /* set Priority for Systick Interrupt */

}

//It also has the problem.

3.

After I changed

     "LPC_GPIO3->IBE  &=~(1UL << 5);"   in 2

to "LPC_GPIO3->IBE |= (1UL << 5);",

it looked fine, but I don't understand why.