[参考译文] MSPM0G1506：DAC：CALCTL CALSEL 位

尊敬的 Zane：

启用 CALON 位允许用户校准任何偏移误差、从而实现 DAC 的出色性能。  

CALSEL 位使用户能够选择是否使用出厂修整值、即 一次调整 在最终测试期间或在客户用户案例中使用自校准来校准最佳修整值。 默认为 Factory TRIM、但使用自校准修整将获得更好的结果。

为了实现最佳结果、我们希望使 CALON 位能够启动失调电压误差校准、并使 CALSEL 位能够进行自校准、以校准到最佳修整、从而补偿失调电压误差。 因此、在 Driverlib 中、我们设置  DAC12_CALCTL_CALSEL_SELFCALIBRATIONTRIM。

此致、

Bill

尊敬的 Bill：

我对 M0G1507-LP 进行一些测试、并导入 DAC12_FIXED_VOLTAGE_Vref_INTERNAL_LP_MSPM0G3507_nortos_ticlang 演示、使用万用表测量 PA15 和 GND。

我使用以下代码测试 ADC 校准功能：

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#include "ti_msp_dl_config.h"

/*
 * DAC12 Reference Voltage in mV
 *  Adjust this value according to DAC12 reference settings in SysConfig
 *    Or, in registers CTL1.REFSN and CTL1.REFSP
 */
#define DAC12_REF_VOLTAGE_mV (2500)
/*
 * DAC12 static output voltage in mV
 *  Adjust output as needed and check in DAC_OUT pin
 */
#define DAC12_OUTPUT_VOLTAGE_mV (100)

int main(void)
{
    uint32_t DAC_value;
    uint32_t DAC_CALDATA;

    uint32_t realdata;



    SYSCFG_DL_init();

    DL_DAC12_performSelfCalibrationBlocking(DAC0);

    DAC_CALDATA = DL_DAC12_getCalibrationData(DAC0);



    /* Set output voltage:
     *  DAC value (12-bits) = DesiredOutputVoltage x 4095
     *                          -----------------------
     */
    DAC_value = (DAC12_OUTPUT_VOLTAGE_mV * 4095) / DAC12_REF_VOLTAGE_mV;

    realdata = DAC_value + DAC_CALDATA;

    DL_DAC12_output12(DAC0, realdata);
    DL_DAC12_enable(DAC0);

    while (1) {
        __WFI();
    }
}

何时 #define DAC12_OUTPUT_VOLTAGE_mV (1000)

不执行校准：PA15 电压为 0.991V

执行校准并添加 CALDATA：PA15 电压为 1.030V

当#define 时 DAC12_OUTPUT_VOLTAGE_mV (100)

不执行校准：PA15 电压为 99.1mV

执行校准并添加 CALDATA：PA15 电压为 138.4mV

从测试结果可以看出：DAC 校准后、DAC 输出精度会变差。

尊敬的 Zane：

我对您在上面提供的代码做了一些调整。

#include "ti_msp_dl_config.h"

/*
 * DAC12 Reference Voltage in mV
 *  Adjust this value according to DAC12 reference settings in SysConfig
 *    Or, in registers CTL1.REFSN and CTL1.REFSP
 */
#define DAC12_REF_VOLTAGE_mV (2500)
/*
 * DAC12 static output voltage in mV
 *  Adjust output as needed and check in DAC_OUT pin
 */
#define DAC12_OUTPUT_VOLTAGE_mV (2000)



int main(void)
{
    uint32_t DAC_value;
    uint32_t DAC_CALDATA;
    uint32_t realdata;

    SYSCFG_DL_init();
    // DL_DAC12_performSelfCalibrationBlocking(DAC0);

    // DAC_CALDATA = DL_DAC12_getCalibrationData(DAC0);
    /* Set output voltage:
     *  DAC value (12-bits) = DesiredOutputVoltage x 4095
     *                          -----------------------
     *                              ReferenceVoltage
     */
    DAC_value = (DAC12_OUTPUT_VOLTAGE_mV * 4095) / DAC12_REF_VOLTAGE_mV;
    DL_DAC12_enable(DAC0);
    
    DL_DAC12_performSelfCalibrationBlocking(DAC0);
    DAC_CALDATA = DL_DAC12_getCalibrationData(DAC0);
    realdata = DAC_value - DAC_CALDATA;
    DL_DAC12_output12(DAC0, realdata);
    // DL_DAC12_output12(DAC0, DAC_value);

    while (1) {
        __WFI();
    }
}

未经过校准且使用电压输出 1000mV PA15  测量值： 1.012V  

校准后：PA15 电压为 1.008V

未经校准和电压输出 2000mV、 测得 PA15：2.010V

校准后：PA15 电压为：2.006 V

希望这对您有所帮助。

此致、

Bill