[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
//

您好！

更简单的一点是：如果 ADC ISR 运行时间太长、则 ADC 将有时间覆盖结果寄存器、然后 CPU 才能获取该值。 在这种情况下、ADCRESULTx 寄存器将被覆盖。 在我发布的示例中、ISR 必须在少于20个 ADCCLK 周期的时间内执行。 如果 ISR 太长、您可以减慢 ADCCLK 速度或执行其他操作来减慢 ADC 转换速度。  

此致、

Ben Collier

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。