TM4C123x 内部温度传感器 精度问题

  使用TM4C1231D5PZ内部温度传感器对-20℃~70℃的环境进行测量，测得的温度始终比实际环境温度低4~11℃不等；使用LM3S9B92（内部温度传感器）进行同样的测量结果好一些（低3~6℃不等）。想请问：

1、按理来说，芯片在运行时其内部温度应比环境温度高，为何TM4C123x测得的温度比实际温度低？而且LM3S也有相同的现象？

2、有什么方法可以提高TM4C1231D5PZ内部温度传感器的测量精度？（±3℃以内）

原始数据如下：

 ——>以上数据是在温度试验箱内测得，每个温度点都经过足够保温时间，确保芯片温度与环境温度一致。

 ——>以上两个芯片的测量温度都是使用各自datasheet的内部温度传感器计算公式算得。

Susan Yang：

请问您是否有尝试使用TI的示例代码测试呢？您现在的时钟是怎样的？是否有使用PLL？

Susan Yang：

我在办公室测试了一下，官网的例程配合EK-TM4C123GXL

结果还算稳定，23度上下

代码如下

//*****************************************************************************
//
// temperature_sensor.c - Example demonstrating the internal ADC temperature
//sensor.
//
// Copyright (c) 2010-2017 Texas Instruments Incorporated.All rights reserved.
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//notice, this list of conditions and the following disclaimer in the
//documentation and/or other materials provided with the//distribution.
////Neither the name of Texas Instruments Incorporated nor the names of
//its contributors may be used to endorse or promote products derived
//from this software without specific prior written permission.
//// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//// This is part of revision 2.1.4.178 of the Tiva Firmware Development Package.
//
//*****************************************************************************#include <stdbool.h>
#include <stdint.h>
#include "inc/hw_memmap.h"
#include "driverlib/adc.h"
#include "driverlib/gpio.h"
#include "driverlib/pin_map.h"
#include "driverlib/sysctl.h"
#include "driverlib/uart.h"
#include "utils/uartstdio.h"//*****************************************************************************
//
//! \addtogroup adc_examples_list
//! <h1>ADC Temperature Sensor (temperature_sensor)</h1>
//!
//! This example shows how to setup ADC0 to read the internal temperature
//! sensor.
//!
//! NOTE: The internal temperature sensor is not calibrated.This example
//! just takes the raw temperature sensor sample and converts it using the
//! equation found in the LM3S9B96 datasheet.
//!
//! This example uses the following peripherals and I/O signals.You must
//! review these and change as needed for your own board:
//! - ADC0 peripheral
//!
//! The following UART signals are configured only for displaying console
//! messages for this example.These are not required for operation of the
//! ADC.
//! - UART0 peripheral
//! - GPIO Port A peripheral (for UART0 pins)
//! - UART0RX - PA0
//! - UART0TX - PA1
//!
//! This example uses the following interrupt handlers.To use this example
//! in your own application you must add these interrupt handlers to your
//! vector table.
//! - None.
//
//*****************************************************************************//*****************************************************************************
//
// This function sets up UART0 to be used for a console to display information
// as the example is running.
//
//*****************************************************************************
void
InitConsole(void)
{//// Enable GPIO port A which is used for UART0 pins.// TODO: change this to whichever GPIO port you are using.//SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);//// Configure the pin muxing for UART0 functions on port A0 and A1.// This step is not necessary if your part does not support pin muxing.// TODO: change this to select the port/pin you are using.//GPIOPinConfigure(GPIO_PA0_U0RX);GPIOPinConfigure(GPIO_PA1_U0TX);//// Enable UART0 so that we can configure the clock.//SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);//// Use the internal 16MHz oscillator as the UART clock source.//UARTClockSourceSet(UART0_BASE, UART_CLOCK_PIOSC);//// Select the alternate (UART) function for these pins.// TODO: change this to select the port/pin you are using.//GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);//// Initialize the UART for console I/O.//UARTStdioConfig(0, 115200, 16000000);
}//*****************************************************************************
//
// Configure ADC0 for the temperature sensor input with a single sample.Once
// the sample is done, an interrupt flag will be set, and the data will be
// read then displayed on the console via UART0.
//
//*****************************************************************************
int
main(void)
{
#if defined(TARGET_IS_TM4C129_RA0) ||\defined(TARGET_IS_TM4C129_RA1) ||\defined(TARGET_IS_TM4C129_RA2)uint32_t ui32SysClock;
#endif//// 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 pui32ADC0Value[1];//// These variables are used to store the temperature conversions for// Celsius and Fahrenheit.//uint32_t ui32TempValueC;uint32_t ui32TempValueF;//// Set the clocking to run at 20 MHz (200 MHz / 10) using the PLL.When// using the ADC, you must either use the PLL or supply a 16 MHz clock// source.// TODO: The SYSCTL_XTAL_ value must be changed to match the value of the// crystal on your board.//
#if defined(TARGET_IS_TM4C129_RA0) ||\defined(TARGET_IS_TM4C129_RA1) ||\defined(TARGET_IS_TM4C129_RA2)ui32SysClock = SysCtlClockFreqSet((SYSCTL_XTAL_25MHZ |SYSCTL_OSC_MAIN |SYSCTL_USE_PLL |SYSCTL_CFG_VCO_480), 20000000);
#elseSysCtlClockSet(SYSCTL_SYSDIV_10 | SYSCTL_USE_PLL | SYSCTL_OSC_MAIN |SYSCTL_XTAL_16MHZ);
#endif//// Set up the serial console to use for displaying messages.This is just// for this example program and is not needed for ADC operation.//InitConsole();//// 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);//// 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, pui32ADC0Value);//// Use non-calibrated conversion provided in the data sheet.Make// sure you divide last to avoid dropout.//ui32TempValueC = ((1475 * 1023) - (2250 * pui32ADC0Value[0])) / 10230;//// Get Fahrenheit value.Make sure you divide last to avoid dropout.//ui32TempValueF = ((ui32TempValueC * 9) + 160) / 5;//// Display the temperature value on the console.//UARTprintf("Temperature = %3d*C or %3d*F\r", ui32TempValueC,ui32TempValueF);//// This function provides a means of generating a constant length// delay.The function delay (in cycles) = 3 * parameter.Delay// 250ms arbitrarily.//
#if defined(TARGET_IS_TM4C129_RA0) ||\defined(TARGET_IS_TM4C129_RA1) ||\defined(TARGET_IS_TM4C129_RA2)SysCtlDelay(ui32SysClock / 12);
#elseSysCtlDelay(SysCtlClockGet() / 12);
#endif}
}

灰小子：

可以通过手工校准来提高测量精度

user5960408：

回复 Susan Yang:

不知道你的办公室室温是多少？我也用这个官方例程配合EK-TM4C123GXL试过，稳定在22、23℃，但我的室温是29℃。

user5960408：

回复 Susan Yang:

1、没有使用TI示例代码，但也差不多；时钟使用PLL，4分频，即50Hz；

2、用TI示例代码配合EK-TM4C123GXL得到的温度（23）也比实际室温（29）低6℃左右；

TM4C1231D5PZ具体代码如下结构；

首先初始化：

ROM_SysCtlClockSet( SYSCTL_SYSDIV_4 | SYSCTL_USE_PLL | SYSCTL_OSC_MAIN | SYSCTL_XTAL_25MHZ );

ROM_SysCtlPeripheralEnable( SYSCTL_PERIPH_ADC0 );

/* configure internal ADC ONLY used for internal temperature */

ROM_ADCSequenceConfigure( ADC0_BASE, 0, ADC_TRIGGER_PROCESSOR, 0 );  /* ADC module 0, sequence 0 ,processor trigger, highest priority */

ROM_ADCHardwareOversampleConfigure( ADC0_BASE, 64 );    /*set 64x hardware oversampling */

ROM_ADCSequenceStepConfigure( ADC0_BASE, 0, 0, ADC_CTL_END | ADC_CTL_TS ); 

ROM_ADCSequenceEnable( ADC0_BASE, 0 ); /*  enable sequence */

 

然后在主循环中触发和读取：

While(1)

{

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ul_loop_count++;

If(ul_loop_count >= 10000)

{

ul_loop_count = 0;

}

switch( ul_loop_count )

{

case 1:

ROM_ADCProcessorTrigger( ADC0_BASE, 0 );

break;

case 200:

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break;

case 500:

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break;

case 700:

ROM_ADCSequenceDataGet( ADC0_BASE, 0, &ul_ADC0_values[ 0 ] );

break;

case 1000:

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break;

}

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}

 

user5960408：

回复 灰小子:

没别的办法话只能通过我测出来的曲线去校准了。。

xyz549040622：

回复 user5960408:

本来就是测芯片温度的，用这个测环境温度还是算了。