[参考译文] TM4C1294NCPDT：ADC 模拟信号：AIN16-19 (IO PK1-3)在软件中不工作

尊敬的 Tzipi：

 很抱歉我刚从旅行回来。 我在 LaunchPad 上将 PK2连接到3.3V 的情况下为 AIN18运行以下代码。 我可以看到它转换为4096。 请在下面找到这些信息、您能试一下吗？

#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 AIN18/PK2.
//!
//! 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 AIN18 pin)
//! - AIN18 - PK2
//!
//! 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.
//
//*****************************************************************************
#define USER_LED1  GPIO_PIN_2

#define SEQNUM 3
//*****************************************************************************
//
// 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_SYSTEM);

    //
    // 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, 120000000);
}

//*****************************************************************************
//
// 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)
{
    uint32_t ui32SysClock;

    //
    // This array is used for storing the data read from the ADC FIFO.
    //
    uint32_t pui32ADC0Value[0];

    //
    // 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.
    //

    ui32SysClock = SysCtlClockFreqSet((SYSCTL_XTAL_25MHZ |
                                       SYSCTL_OSC_MAIN |
                                       SYSCTL_USE_PLL |
                                       SYSCTL_CFG_VCO_240), 120000000);

    //
    // 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");

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

    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOK);

    /*
     * ADC Clock runs at 30Mhz
     */
//    ADCClockConfigSet(ADC0_BASE, ADC_CLOCK_SRC_PLL, 10);


    /* PK2 - AIN18
     */

    GPIOPinTypeADC(GPIO_PORTK_BASE, GPIO_PIN_2 );

    ADCSequenceConfigure(ADC0_BASE, SEQNUM, ADC_TRIGGER_PROCESSOR, 0);

    ADCSequenceStepConfigure(ADC0_BASE, SEQNUM, 0, ADC_CTL_CH18 | ADC_CTL_IE |
                             ADC_CTL_END);

    ADCSequenceEnable(ADC0_BASE, SEQNUM);

    ADCIntClear(ADC0_BASE, SEQNUM);

    while(1)
    {


        //
        // Trigger the ADC conversion.
        //

        ADCProcessorTrigger(ADC0_BASE, SEQNUM);

        //
        // Wait for conversion to be completed.
        //
        while(!ADCIntStatus(ADC0_BASE, SEQNUM, false))
        {
        }

        //
        // Clear the ADC interrupt flag.
        //
        ADCIntClear(ADC0_BASE, SEQNUM);

        //
        // Read ADC Value.
        //
        ADCSequenceDataGet(ADC0_BASE, SEQNUM, pui32ADC0Value);

        //
        // Display the AIN18 (PK2) digital value on the console.
        //
        UARTprintf("AIN18 = %4d\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(ui32SysClock / 100);

    }
}

对于上面的代码我使用、采样序列3被使用。 以下是与 SS3相关的寄存器设置。