[原创] LM3S8962学习(四) -- 温度传感器

上次使用学习了一下Timer，每隔1秒钟中断一次，现在准备实现每隔1S钟读取一下内部的温度值，并在LCD上显示出来。

从手册288页上可以看出，LM3S8962的内部温度传感器有两个目的：

1．  防止温度过高或过低，影响系统芯片正常运行

2．  校准RTC，这个以后想玩玩，看看实际的效果

实现读取内部传感器值，需要有以下几步：

1．  使能ADC，内部传感器的值是通过ADC获取的

    SysCtlPeripheralEnable( SYSCTL_PERIPH_ADC );

SysCtlADCSpeedSet( SYSCTL_ADCSPEED_250KSPS );

2．  配置ADC

    ADCReferenceSet(ADC_BASE, ADC_REF_INT);//设置ADC参考电压为内部电压

    ADCSequenceDisable(ADC_BASE, 3); //禁止ADC采样

    ADCSequenceConfigure(ADC_BASE, 3, ADC_TRIGGER_PROCESSOR, 0);//设置ADC为处理器事件

    ADCSequenceStepConfigure(ADC_BASE, 3, 0, (ADC_CTL_TS | ADC_CTL_END | ADC_CTL_IE));//采样温度值结束后并申请中断

ADCSequenceEnable(ADC_BASE, 3);//使能ADC采样

3．  触发一次ADC采样

ADCProcessorTrigger(ADC_BASE, 3);

要不然得不到正确的温度值

通过以上的配置，配合Timer中断，我们在LCD上可以看到如下显示：

Temp is

00026

如果要使得效果更叫的明显一点，可以对这芯片哈口气，数值会剧烈变化，哈哈

实验代码如下：

#include "inc/hw_ints.h"

#include "inc/hw_memmap.h"

#include "inc/hw_types.h"

#include "driverlib/debug.h"

#include "driverlib/gpio.h"

#include "driverlib/interrupt.h"

#include "driverlib/sysctl.h"

#include "driverlib/timer.h"

#include "drivers/rit128x96x4.h"

#include "inc/hw_adc.h"

#include "driverlib/ADC.h"

 #define LED GPIO_PIN_0

unsigned long cnt, adc_val;

unsigned long adc_isr_ret;

char bcd[10];

void

Timer0IntHandler(void)

{                

 TimerIntClear(TIMER0_BASE, TIMER_TIMA_TIMEOUT);

           GPIOPinWrite(GPIO_PORTF_BASE, LED, LED^GPIOPinRead(GPIO_PORTF_BASE,LED));    

    ADCProcessorTrigger(ADC_BASE, 3);

          ADCSequenceDataGet(ADC_BASE, 3, &adc_val);

    adc_val = (151040 - 225 * adc_val) / 1024;    

    bcd[0] = (unsigned char)(adc_val / 10000 + 0x30);

    bcd[1] = (unsigned char)((adc_val % 10000) / 1000 + 0x30);

    bcd[2] = (unsigned char)((adc_val % 1000) / 100 + 0x30);

    bcd[3] = (unsigned char)((adc_val % 100) / 10 + 0x30);

    bcd[4] = (unsigned char)((adc_val % 10)  + 0x30);

    RIT128x96x4StringDraw("Temp is:", 10, 40, 10);

    RIT128x96x4StringDraw(bcd, 10, 55, 10);

}

int

main(void)

{

    SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER0);

    SysCtlPeripheralEnable( SYSCTL_PERIPH_ADC );

    SysCtlADCSpeedSet( SYSCTL_ADCSPEED_250KSPS );

          SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);

          GPIODirModeSet(GPIO_PORTF_BASE,LED,GPIO_DIR_MODE_OUT);

          GPIOPadConfigSet(GPIO_PORTF_BASE,LED,GPIO_STRENGTH_4MA, GPIO_PIN_TYPE_STD);

    ADCReferenceSet(ADC_BASE, ADC_REF_INT);

    ADCSequenceDisable(ADC_BASE, 3);

    ADCSequenceConfigure(ADC_BASE, 3, ADC_TRIGGER_PROCESSOR, 0);

    ADCSequenceStepConfigure(ADC_BASE, 3, 0, (ADC_CTL_TS | ADC_CTL_END | ADC_CTL_IE));

    ADCSequenceEnable(ADC_BASE, 3);

    TimerConfigure(TIMER0_BASE, TIMER_CFG_32_BIT_PER);

    TimerLoadSet(TIMER0_BASE, TIMER_A, SysCtlClockGet()/4);

    IntEnable(INT_TIMER0A);

    TimerIntEnable(TIMER0_BASE, TIMER_TIMA_TIMEOUT);

    TimerEnable(TIMER0_BASE, TIMER_A);

          IntMasterEnable();

    RIT128x96x4Init(1000000);

    RIT128x96x4Clear();

    ADCProcessorTrigger(ADC_BASE, 3);

    while(1)

    {  

    }

}