[参考译文] TMS320F2800156-Q1：ADC 测量不稳定-在干净的1.65V 输入上的测量值介于2300和4095之间

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https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/1413648/tms320f2800156-q1-adc-measurements-erratic---measuring-between-2300-and-4095-on-a-clean-1-65v-input

器件型号：TMS320F2800156-Q1

工具与软件：

我正在使用2300和4095计数之间的干净1.65V 输入在多个电路板上测量多个 ADC。计数更有可能接近4095或接近2500、在3000秒内的可能性较低。在 CCS 中观察测量值的同时、它们会在这个范围内随机摆动。

产生1.65V 电压的硬件已在多个电路板上进行了测量、以确保清洁干净。我在3个不同的 ADC 引脚上使用有源运算放大器电路和无源分压器创建了此基准电压、结果都是一样的、因此我确信硬件不是问题。

在我的固件中、我使用与示例相同的代码、且每次转换均由软件触发：

//#############################################################################
//
// FILE:   adc_ex1_soc_software.c
//
// TITLE:  ADC Software Triggering
//
//! \addtogroup driver_example_list
//! <h1>ADC Software Triggering</h1>
//!
//! This example converts some voltages on ADCA and ADCC based on a software
//! trigger.
//!
//! The ADCC will not convert until ADCA is complete, so the ADCs will not run
//! asynchronously. However, this is much less efficient than allowing the ADCs
//! to convert synchronously in parallel (for example, by using an ePWM 
//! trigger).
//!
//! \b External \b Connections \n
//!  - A0, A1, C2, and C3 should be connected to signals to convert
//!
//! \b Watch \b Variables \n
//! - \b myADC0Result0 - Digital representation of the voltage on pin A0
//! - \b myADC0Result1 - Digital representation of the voltage on pin A1
//! - \b myADC1Result0 - Digital representation of the voltage on pin C2
//! - \b myADC1Result1 - Digital representation of the voltage on pin C3
//!
//
//#############################################################################
//
//
// $Copyright:
// Copyright (C) 2024 Texas Instruments Incorporated - http://www.ti.com/
//
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 
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//#############################################################################
//

//
// Included Files
//
#include "driverlib.h"
#include "device.h"
#include "board.h"

//
// Globals
//
uint16_t myADC0Result0;
uint16_t myADC0Result1;
uint16_t myADC1Result0;
uint16_t myADC1Result1;

//
// Main
//
void main(void)
{
    //
    // Initialize device clock and peripherals
    //
    Device_init();

    //
    // Disable pin locks and enable internal pullups.
    //
    Device_initGPIO();

    //
    // Initialize PIE and clear PIE registers. Disables CPU interrupts.
    //
    Interrupt_initModule();

    //
    // Initialize the PIE vector table with pointers to the shell Interrupt
    // Service Routines (ISR).
    //
    Interrupt_initVectorTable();

    //
    // Set up ADCs, initializing the SOCs to be triggered by software
    //
    Board_init();

    //
    // Enable Global Interrupt (INTM) and realtime interrupt (DBGM)
    //
    EINT;
    ERTM;

    //
    // Loop indefinitely
    //
    while(1)
    {
        //
        // Convert, wait for completion, and store results
        //
        ADC_forceMultipleSOC(myADC0_BASE, (ADC_FORCE_SOC0 | ADC_FORCE_SOC1));

        //
        // Wait for ADCA to complete, then acknowledge flag
        //
        while(ADC_getInterruptStatus(myADC0_BASE, ADC_INT_NUMBER1) == false)
        {
        }
        ADC_clearInterruptStatus(myADC0_BASE, ADC_INT_NUMBER1);

        ADC_forceMultipleSOC(myADC1_BASE, (ADC_FORCE_SOC0 | ADC_FORCE_SOC1));
        //
        // Wait for ADCC to complete, then acknowledge flag
        //
        while(ADC_getInterruptStatus(myADC1_BASE, ADC_INT_NUMBER1) == false)
        {
        }
        ADC_clearInterruptStatus(myADC1_BASE, ADC_INT_NUMBER1);

        //
        // Store results
        //
        myADC0Result0 = ADC_readResult(ADCARESULT_BASE, ADC_SOC_NUMBER0);
        myADC0Result1 = ADC_readResult(ADCARESULT_BASE, ADC_SOC_NUMBER1);
        myADC1Result0 = ADC_readResult(ADCCRESULT_BASE, ADC_SOC_NUMBER0);
        myADC1Result1 = ADC_readResult(ADCCRESULT_BASE, ADC_SOC_NUMBER1);

        //
        // Software breakpoint. At this point, conversion results are stored in
        // myADC0Result0, myADC0Result1, myADC1Result0, and myADC1Result1.
        //
        // Hit run again to get updated conversions.
        //
        ESTOP0;
    }
}

我与示例代码的唯一偏差是我仅使用 ADCA、而不是两个 ADC。我的 syscfg 中可能与此相关的其他设置包括：

ADC 基准电压=内部、2.5V

ADC 时钟预分频器=时钟/4.0

优先级模式=所有轮询

是否有任何已知的 gotcha 可导致固件出现这种行为？

1 年多前