Hi, I use internal sensor of TM4C1294NCPDT. When i read positive degrees it works fine but when i want to read negative degrees it always shows zero degree. What is my mistake?
#define PART_TM4C129
#include <stdint.h>
#include <stdbool.h>
#include "stdlib.h"
#include "inc/hw_ints.h"
#include "inc/hw_memmap.h"
#include "inc/hw_uart.h"
#include "inc/hw_gpio.h"
#include "inc/hw_pwm.h"
#include "inc/hw_types.h"
#include "driverlib/adc.h"
#include "driverlib/timer.h"
#include "driverlib/gpio.h"
#include "driverlib/interrupt.h"
#include "driverlib/pin_map.h"
#include "driverlib/rom.h"
#include "driverlib/rom_map.h"
#include "driverlib/sysctl.h"
#include "driverlib/uart.h"
#include "driverlib/udma.h"
#include "driverlib/pwm.h"
#include "driverlib/ssi.h"
#include "driverlib/systick.h"
#include "driverlib/adc.h"
#include <string.h>
void setup() {
Serial.begin(9600);
}
void loop(){
// SysCtlClockSet(SYSCTL_SYSDIV_2_5|SYSCTL_USE_PLL|SYSCTL_OSC_MAIN|SYSCTL_XTAL_16MHZ);
// InitConsole();
//
// This array is used for storing the data read from the ADC FIFO. It
// must be as large as the FIFO for the sequencer in use. This example
// uses sequence 3 which has a FIFO depth of 1. If another sequence
// was used with a deeper FIFO, then the array size must be changed.
//
uint32_t ADCValues[1];
//
// These variables are used to store the temperature conversions for
// Celsius and Fahrenheit.
//
uint32_t TempValueC ;
uint32_t TempValueF ;
//
// Display the setup on the console.
//
/* UARTprintf("ADC ->\n");
UARTprintf(" Type: Internal Temperature Sensor\n");
UARTprintf(" Samples: One\n");
UARTprintf(" Update Rate: 250ms\n");
UARTprintf(" Input Pin: Internal temperature sensor\n\n");*/
//
// The ADC0 peripheral must be enabled for use.
//
SysCtlPeripheralEnable(SYSCTL_PERIPH_ADC0);
SysCtlDelay(3);
//
// Enable sample sequence 3 with a processor signal trigger. Sequence 3
// will do a single sample when the processor sends a singal to start the
// conversion. Each ADC module has 4 programmable sequences, sequence 0
// to sequence 3. This example is arbitrarily using sequence 3.
//
ADCSequenceConfigure(ADC0_BASE, 3, ADC_TRIGGER_PROCESSOR, 0);
//
// Configure step 0 on sequence 3. Sample the temperature sensor
// (ADC_CTL_TS) and configure the interrupt flag (ADC_CTL_IE) to be set
// when the sample is done. Tell the ADC logic that this is the last
// conversion on sequence 3 (ADC_CTL_END). Sequence 3 has only one
// programmable step. Sequence 1 and 2 have 4 steps, and sequence 0 has
// 8 programmable steps. Since we are only doing a single conversion using
// sequence 3 we will only configure step 0. For more information on the
// ADC sequences and steps, reference the datasheet.
//
ADCSequenceStepConfigure(ADC0_BASE, 3, 0, ADC_CTL_TS | ADC_CTL_IE |
ADC_CTL_END);
//
// Since sample sequence 3 is now configured, it must be enabled.
//
ADCSequenceEnable(ADC0_BASE, 3);
//
// Clear the interrupt status flag. This is done to make sure the
// interrupt flag is cleared before we sample.
//
ADCIntClear(ADC0_BASE, 3);
//
// Sample the temperature sensor forever. Display the value on the
// console.
//
while(1)
{
//
// Trigger the ADC conversion.
//
ADCProcessorTrigger(ADC0_BASE, 3);
//
// Wait for conversion to be completed.
//
while(!ADCIntStatus(ADC0_BASE, 3, false))
{
}
//
// Clear the ADC interrupt flag.
//
ADCIntClear(ADC0_BASE, 3);
//
// Read ADC Value.
//
ADCSequenceDataGet(ADC0_BASE, 3, ADCValues);
//
// Use non-calibrated conversion provided in the data sheet. I use floats in intermediate
// math but you could use intergers with multiplied by powers of 10 and divide on the end
// Make sure you divide last to avoid dropout.
//
TempValueC = (uint32_t)(147.5 - ((75.0*3.3 *(float)ADCValues[0])) / 4096.0);
//
// Get Fahrenheit value. Make sure you divide last to avoid dropout.
//
TempValueF = ((TempValueC * 9) + 160) / 5;
//
// Display the temperature value on the console.
//
Serial.print("Temperature = C ");
Serial.print(TempValueC, DEC);
Serial.println(" ");
Serial.print("Temperature = F ");
Serial.print(TempValueF, DEC);
//
// This function provides a means of generating a constant length
// delay. The function delay (in cycles) = 3 * parameter. Delay
// 250ms arbitrarily.
//
SysCtlDelay(80000000 / 12);
}
}
