[参考译文] TMS320F28069M：ADC 中的同步采样模式

Hi Dev、

遗憾的是、没有现有的示例可用于同步、但我已对 Adsome wiex-example 进行了快速修改、以回答您的第二个问题。 在此消息的底部、我包含了一个新的.c 文件、您可以使用它来替换 Adexc 示例中的2806xAdc.c 文件。  

使用新文件、我启用了 SOC0和 SOC1的同步采样、两者都由来自 ePWM 的相同信号触发。 SOC0对 ADCINA2/ADCINB2进行采样、而 SOC1对 ADCINA4/ADCINB4进行采样。 当任一 SOC 完成 ADCINA 转换时、结果存储在 ADCRESULT0中、而 ADCINB 转换存储在 ADCRESULT1中。

我已经设置了一个名为 ADC_ISR 的 ADC 中断、该中断由 EOC1信号触发。 使用 INTPULSEPOS 寄存器、EOC1设置为在 ADCRESULT1锁存并准备就绪时触发 ADC_ISR、这始终在 ADCRESULT0准备就绪后触发。 数据表中的图8-27和下面的屏幕截图显示了该时序。  

ADC_ISR 仅从 ADCRESULT0获取结果、并将其放入称为 Voltage1的数组中、然后将 ADCRESULT1放入 Voltage2中。 由于 SOC0和 SOC1将始终同时触发、因此每个"电压"阵列中的结果在 SOC0和 SOC1之间交替变化。 在我的示例中、我将采样引脚从 SOC0接地、同时将 SOC1连接到3.3V。 这使得数组中的值在高电平(~4000)和低电平(~0)之间交替、如下所示。  

在我的示例中、我已使用跳线连接：

ADCINA2 => GPIO14 (低电平)  

ADCINB2 => GPIO15 (低电平)

ADCINA4 => GPIO11 (高电平)

ADCINB4 => GPIO12 (高电平)

只要您将 ADC 输入连接到正确的高电压和低电压、您就应该在 Voltage1和 Voltage2数组中看到交替值。 这显示了 ADC_ISR 在 ADCRESULT 寄存器被覆盖之前将 ADC 结果保存在存储器的其他位置。  

此致、
Ben Collier

//###########################################################################
//
// FILE:   Example_2806xAdcSoc.c
//
// TITLE:  ADC Start of Conversion Example
//
//! \addtogroup f2806x_example_list
//! <h1> ADC Start of Conversion (adc_soc)</h1>
//! 
//! This ADC example uses ePWM1 to generate a periodic ADC SOC - ADCINT1.
//! Two channels are converted, ADCINA4 and ADCINA2.
//! 
//! \b Watch \b Variables \n
//! - Voltage1[10]    - Last 10 ADCRESULT0 values
//! - Voltage2[10]    - Last 10 ADCRESULT1 values
//! - ConversionCount - Current result number 0-9
//! - LoopCount       - Idle loop counter
//
//###########################################################################
// $TI Release: $
// $Release Date: $
// $Copyright:
// Copyright (C) 2009-2022 Texas Instruments Incorporated - http://www.ti.com/
//
// 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.
// $
//###########################################################################

//
// Included Files
//
#include "DSP28x_Project.h"     // Device Headerfile and Examples Include File

//
// Function Prototypes
//
__interrupt void adc_isr(void);
void Adc_Config(void);

//
// Globals
//
Uint16 LoopCount;
Uint16 ConversionCount;
Uint16 Voltage1[100];
Uint16 Voltage2[100];

//
// Main
// 
void main(void)
{
    //
    // Step 1. Initialize System Control:
    // PLL, WatchDog, enable Peripheral Clocks
    // This example function is found in the F2806x_SysCtrl.c file.
    //
    InitSysCtrl();

    //
    // Step 2. Initialize GPIO:
    // This example function is found in the F2806x_Gpio.c file and
    // illustrates how to set the GPIO to it's default state.
    //
    // InitGpio();  // Skipped for this example

    //
    // Step 3. Clear all interrupts and initialize PIE vector table:
    // Disable CPU interrupts
    //
    DINT;

    //
    // Initialize the PIE control registers to their default state.
    // The default state is all PIE interrupts disabled and flags
    // are cleared.
    // This function is found in the F2806x_PieCtrl.c file.
    //
    InitPieCtrl();

    //
    // Disable CPU interrupts and clear all CPU interrupt flags:
    //
    IER = 0x0000;
    IFR = 0x0000;

    //
    // Initialize the PIE vector table with pointers to the shell Interrupt
    // Service Routines (ISR).
    // This will populate the entire table, even if the interrupt
    // is not used in this example.  This is useful for debug purposes.
    // The shell ISR routines are found in F2806x_DefaultIsr.c.
    // This function is found in F2806x_PieVect.c.
    //
    InitPieVectTable();

    //
    // Interrupts that are used in this example are re-mapped to
    // ISR functions found within this file.
    //
    EALLOW;  // This is needed to write to EALLOW protected register
    PieVectTable.ADCINT1 = &adc_isr;
    EDIS;    // This is needed to disable write to EALLOW protected registers

    //
    // Step 4. Initialize all the Device Peripherals:
    // This function is found in F2806x_InitPeripherals.c
    // InitPeripherals(); // Not required for this example
    //
    InitAdc();  // For this example, init the ADC
    AdcOffsetSelfCal();

    //
    // Step 5. User specific code, enable interrupts:
    //

    //
    // Enable ADCINT1 in PIE
    //
    PieCtrlRegs.PIEIER1.bit.INTx1 = 1; // Enable INT 1.1 in the PIE
    IER |= M_INT1; 					   // Enable CPU Interrupt 1
    EINT;          					   // Enable Global interrupt INTM
    ERTM;          					   // Enable Global realtime interrupt DBGM

    LoopCount = 0;
    ConversionCount = 0;

    //
    // Configure ADC
    //
    EALLOW;

    //
    // Enable an GPIO output on GPIO14 and GPIO15, set it high
    //
    GpioCtrlRegs.GPAPUD.bit.GPIO14 = 1;   // Enable pullup on GPIO14
    GpioDataRegs.GPASET.bit.GPIO14 = 0;   // Load output latch
    GpioCtrlRegs.GPAMUX1.bit.GPIO14 = 0;  // GPIO14 = GPIO14
    GpioCtrlRegs.GPADIR.bit.GPIO14 = 1;   // GPIO14 = output

    GpioCtrlRegs.GPAPUD.bit.GPIO15 = 1;   // Enable pullup on GPIO15
    GpioDataRegs.GPASET.bit.GPIO15 = 0;   // Load output latch
    GpioCtrlRegs.GPAMUX1.bit.GPIO15 = 0;  // GPIO15 = GPIO15
    GpioCtrlRegs.GPADIR.bit.GPIO15 = 1;   // GPIO15 = output

    GpioCtrlRegs.GPAPUD.bit.GPIO11 = 0;   // Enable pullup on GPIO11
    GpioDataRegs.GPASET.bit.GPIO11 = 1;   // Load output latch
    GpioCtrlRegs.GPAMUX1.bit.GPIO11 = 0;  // GPIO11 = GPIO11
    GpioCtrlRegs.GPADIR.bit.GPIO11 = 1;   // GPIO11 = output

    GpioCtrlRegs.GPAPUD.bit.GPIO12 = 0;   // Enable pullup on GPIO12
    GpioDataRegs.GPASET.bit.GPIO12 = 1;   // Load output latch
    GpioCtrlRegs.GPAMUX1.bit.GPIO12 = 0;  // GPIO12 = GPIO12
    GpioCtrlRegs.GPADIR.bit.GPIO12 = 1;   // GPIO12 = output

    //
    // Enable Simultaneous Sampling
    //
    AdcRegs.ADCSAMPLEMODE.bit.SIMULEN0 = 1;

    //
    // Set SOC0 and SOC1 to high priority
    //
    //AdcRegs.SOCPRICTL.bit.SOCPRIORITY = 2;



    AdcRegs.ADCCTL2.bit.ADCNONOVERLAP = 1; // Enable non-overlap mode
    
    //
    // ADCINT1 trips after AdcResults latch, called "Late Interrupt Pulse" in datasheet / TRM
    //
    AdcRegs.ADCCTL1.bit.INTPULSEPOS	= 1;
    
    AdcRegs.INTSEL1N2.bit.INT1E     = 1;  // Enabled ADCINT1
    AdcRegs.INTSEL1N2.bit.INT1CONT  = 0;  // Disable ADCINT1 Continuous mode
    
    //
    // setup EOC1 to trigger ADCINT1 to fire
    //
    AdcRegs.INTSEL1N2.bit.INT1SEL 	= 1;
    
    AdcRegs.ADCSOC0CTL.bit.CHSEL 	= 2;  // set SOC0 channel select to ADCINA2
    AdcRegs.ADCSOC1CTL.bit.CHSEL 	= 4;  // set SOC1 channel select to ADCINA4
    
    //
    // set SOC0 start trigger on EPWM1A, due to round-robin SOC0 converts
    // first then SOC1
    //
    AdcRegs.ADCSOC0CTL.bit.TRIGSEL 	= 5;
    
    //
    // set SOC1 start trigger on EPWM1A, due to round-robin SOC0 converts 
    // first then SOC1
    //
    AdcRegs.ADCSOC1CTL.bit.TRIGSEL 	= 5;
    
    //
    // set SOC0 S/H Window to 7 ADC Clock Cycles, (6 ACQPS plus 1)
    //
    AdcRegs.ADCSOC0CTL.bit.ACQPS 	= 6;
    
    //
    // set SOC1 S/H Window to 7 ADC Clock Cycles, (6 ACQPS plus 1)
    //    
    AdcRegs.ADCSOC1CTL.bit.ACQPS 	= 6;
    EDIS;

    //
    // Assumes ePWM1 clock is already enabled in InitSysCtrl();
    //
    EPwm1Regs.ETSEL.bit.SOCAEN	= 1;		// Enable SOC on A group
    EPwm1Regs.ETSEL.bit.SOCASEL	= 4;		// Select SOC from CMPA on upcount
    EPwm1Regs.ETPS.bit.SOCAPRD 	= 1;		// Generate pulse on 1st event
    EPwm1Regs.CMPA.half.CMPA 	= 0x0080;	// Set compare A value
    EPwm1Regs.TBPRD 			= 0xFFFF;	// Set period for ePWM1
    EPwm1Regs.TBCTL.bit.CTRMODE	= 0;		// count up and start

    //
    // Wait for ADC interrupt
    //
    for(;;)
    {
        LoopCount++;
    }
}

//
// adc_isr - 
//
__interrupt void
adc_isr(void)
{
    Voltage1[ConversionCount] = AdcResult.ADCRESULT0;
    Voltage2[ConversionCount] = AdcResult.ADCRESULT1;
    
    //
    // If 20 conversions have been logged, start over
    //
    if(ConversionCount == 99)
    {
        ConversionCount = 0;
    }
    else
    {
        ConversionCount++;
    }

    //
    // Clear ADCINT1 flag reinitialize for next SOC
    //
    AdcRegs.ADCINTFLGCLR.bit.ADCINT1 = 1;
    
    PieCtrlRegs.PIEACK.all = PIEACK_GROUP1;   // Acknowledge interrupt to PIE

    return;
}

//
// End of File
//

Hi Dev、

很抱歉、我们花了很长时间才回复您。 我仍在努力寻找这个问题的原因、我在本周五与更多 ADC 专家举行了另一次会议。 当我们找到解决方案时、我会告诉您。

此致、

Ben Collier

Hi Dev、

是否可以尝试在 SOC 14而非15末尾触发中断？ 如果这不起作用、我可以发送我编辑过的示例、该示例成功地使用相同的触发器触发和采样所有 SOC。

此致、

Ben Collier

您好 Benjamin、

没问题。 我们可以在将来对此进行讨论。 如果我们将 EOC14保持为 ADCINT 的中断源、则根据最新更新。 一切都按预期正常工作。