TM4C123GH6PM 调试ADC时遇到的问题

楼主可以参考官方多通道采样的例子。单通道采样时没有问题的么？

请问哪有多通道的例程？

我在采样的时候，一样的输入电压，经常采到差别很大的值，1.65V的电压直接接到PE3，采到的经常在1900和1200之间波动，不知道为什么？

另外，我只接了PE3，为什么其他几路ADC也会采到很大的值，我用示波器测这些引脚，发现都有1-2V的电压，为什么呢

参考tivaware中评估板对应的qs-logger历程。有用两个独立的ADC进行多通道采样的历程。

我在采样的时候，一样的输入电压，经常采到差别很大的值，1.65V的电压直接接到PE3，采到的经常在1900和1200之间波动，不知道为什么？

另外，我只接了PE3，为什么其他几路ADC也会采到很大的值，我用示波器测这些引脚，发现都有1-2V的电压，为什么呢

不用的接地或接高，看是不是对的值，0或者FFF/FFE之类

我试试去，不应该有这么大的误差的，除非你前级的电压本来误差就很大。而且你的这句话，用示波器量这些引脚，你用万用表量看看。

好的，万用表倒是没测过，我试试

不接高不接地，采样值不是000也不是fff，就是随机数

这个是肯定的，因为这个电压是随机的，接VCC或者GND呢，AD的值是什么

TM4C123FH6PM的34、35、36不是xosc0和xosc1，可以使用实时时钟模块吗？文档说“在 RTC 模式中，要求 CCP0 输入时钟为 32.768 KHz。然后将时钟信号分频为 1 Hz，将其传送给计数器的输入端。”   CCP0是1脚或28脚，是不是把这些脚软件上配置成ccp0，硬件上接上晶振就可以呢

TM4C123GH6PM是可以接一个32.768KHZ来使用实时时钟模块的。

一脚应该是不可以的，因为手册上说，要使用32位实时时钟，定时器需要在CCP的偶数管脚上有一个32.768KHz的输入信号。是偶数管脚。

再次看了看手册，TM4C123中有两个RTC，一个是定时器配置为RTC模式，一个需要用到CPP0引脚。一个是休眠模块的RTC，需要用到晶振或者内部振荡器，两者是不一样的。

经过测试，悬空的时候，确实采集到的值会乱跳。AIN0接GND，在0-3之间跳动，接VCC，稳定采集4095，没你说的那么大的误差，也是用的LaunchPad

我再试试，我测的是1.65V，跳的挺大。

//*****************************************************************************
//
// single_ended.c - Example demonstrating how to configure the ADC for
//                  single ended operation.
//
// Copyright (c) 2010-2014 Texas Instruments Incorporated.  All rights reserved.
// Software License Agreement
// 
//   Redistribution and use in source and binary forms, with or without
//   modification, are permitted provided that the following conditions
//   are met:
//
//   Redistributions of source code must retain the above copyright
//   notice, this list of conditions and the following disclaimer.
//
//   Redistributions in binary form must reproduce the above copyright
//   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,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// 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 2.1.0.12573 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>Single Ended ADC (single_ended)</h1>
//!
//! This example shows how to setup ADC0 as a single ended input and take a
//! single sample on AIN0/PE7.
//!
//! This example uses the following peripherals and I/O signals.  You must
//! review these and change as needed for your own board:
//! - ADC0 peripheral
//! - GPIO Port E peripheral (for AIN0 pin)
//! - AIN0 - PE7
//!
//! 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 a single-ended input and a single sample.  Once the
// sample is ready, an interrupt flag will be set.  Using a polling method,
// the data will be read then displayed on the console via UART0.
//
//*****************************************************************************
int
main(void)
{
    //
    // 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];

    //
    // 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.
    //
    SysCtlClockSet(SYSCTL_SYSDIV_10 | SYSCTL_USE_PLL | SYSCTL_OSC_MAIN |
                   SYSCTL_XTAL_16MHZ);

    //
    // 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: Single Ended\n");
    UARTprintf("  Samples: One\n");
    UARTprintf("  Update Rate: 250ms\n");
    UARTprintf("  Input Pin: AIN0/PE7\n\n");

    //
    // The ADC0 peripheral must be enabled for use.
    //
    SysCtlPeripheralEnable(SYSCTL_PERIPH_ADC0);

    //
    // For this example ADC0 is used with AIN0 on port E7.
    // The actual port and pins used may be different on your part, consult
    // the data sheet for more information.  GPIO port E needs to be enabled
    // so these pins can be used.
    // TODO: change this to whichever GPIO port you are using.
    //
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOE);

    //
    // Select the analog ADC function for these pins.
    // Consult the data sheet to see which functions are allocated per pin.
    // TODO: change this to select the port/pin you are using.
    //
    GPIOPinTypeADC(GPIO_PORTE_BASE, GPIO_PIN_3);

    //
    // Enable sample sequence 3 with a processor signal trigger.  Sequence 3
    // will do a single sample when the processor sends a signal 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 channel 0 (ADC_CTL_CH0) in
    // single-ended mode (default) 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_CH0 | 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 AIN0 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);

        //
        // Display the AIN0 (PE7) digital value on the console.
        //
        UARTprintf("AIN0 = %4d\r\n", pui32ADC0Value[0]);

        //
        // This function provides a means of generating a constant length
        // delay.  The function delay (in cycles) = 3 * parameter.  Delay
        // 250ms arbitrarily.
        //
        SysCtlDelay(SysCtlClockGet() / 12);
    }
}

这是我测试的例程，用的是PE3，AIN0

由于串口问题，我只能用的单步调试看的变量的值，我是用杜邦线连接PE3和函数信号发生器，刚刚试了这段代码，循环多次，采样值也是跳动很大，难道是我的测试电路不对吗？  

不知道您是怎么输入电压信号到PE3的？您是通过串口来看采样值的吧

我是通过串口打印输出值的，杜邦线直接连接PE3和VCC和GND打印输出的。你是如何测试的呢？串口不能用的话，CCS单步调试，看这个值的变化吧。

循环多次，值变化蛮大的，来去1000都有

你看，这是我搞定串口后用你给的程序测的。来去已经变小了，但是还是有一两百多

首先怀疑你外部输入的信号波动就是这么大的问题。你接VCC试试，肯定不会这么跳的厉害的。

为什么我的示波器纵轴显示范围一直在86到326？？前半部分的曲线看不到，不管观测值如何变化，超过326和低于86的值就看不到。

重新建立示波器，范围会变化，但是曲线还是会上下的削顶超出范围，而不能全部显示。

按了那个放大镜，应该是自适应，选择了both方向，也没什么用

什么叫做悬空呀，测试的时候不是直接接到PE3吗

我用杜邦线直接连接PE3和GND，输出值是3或4或5，连接VCC是4095，但是直接外接一个电压用万用表测了，电压稳定，输出值是0、4095，中间还加一些其他的数，完全不是我要测的电压，电压在0-3.3的，还是外接的时候要接上其他接口，

您好，我在测4路的时候也遇到这些问题测出的数据不准，调动很大，您是怎么解决的