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16位 MSP430FR2353 芯片P1.7引脚配置成VREF+输出2.5V 如何配置？

user5707170
Intellectual 580 points
Other Parts Discussed in Thread: MSP430FR2353

16位  MSP430FR2353 芯片P1.7引脚配置成VREF+输出2.5V 如何配置？

下面是我的配置

  WDTCTL = WDTPW + WDTHOLD;                 // Stop watchdog timer
  PM5CTL0 &= ~LOCKLPM5;                     // Disable the GPIO power-on default high-impedance mode
                                            // to activate previously configured port settings
  P1SEL0 |= BIT7;
  P1SEL1 |= BIT7;
  // Configure reference module
  PMMCTL0_H = PMMPW_H;                                      // Unlock the PMM registers
  PMMCTL2 = INTREFEN | REFVSEL_2 | EXTREFEN_1;              // Enable internal 2.5V reference
  while(!(PMMCTL2 & REFGENRDY));                            // Poll till internal reference settles
，但是测量时仅仅测量出来1.2V 我想输出2.5V 不知道怎么配置下  能否提供下例程
  • 0
    TI__Guru**** 252096 points
    您现在是想配置为外部参考电压2.5V？

    您可以参考数据手册

    www.ti.com/.../msp430fr2353.pdf

    The device contains three on-chip references:
    • Internal shared reference (1.5 V, 2.0 V, or 2.5 V)
    • 1.2 V for external reference (VREF pin)
    • 1.2 V low-power reference for eCOMP

    P1.7/UCA0TXD/UCA0SIMO/TB0.2/TDO/OA1+/A7/VREF+ can support a buffered external 1.2-V output when EXTREFEN = 1 in the PMMCTL2 register
  • 0 回复 Susan Yang
    Intellectual 580 points

    我想直接通过这个引脚直接输出2.5V ，作为外部的参考电压

    PMMCTL2 = INTREFEN | REFVSEL_2 | EXTREFEN_1;              // Enable internal 2.5V reference  选择了2.5V 但是输出是2.5V也对这个寄存器操作了

    下面的操作配置还是输出1.2V

    WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer

    PM5CTL0 &= ~LOCKLPM5; // Disable the GPIO power-on default high-impedance mode
    // to activate previously configured port settings
    P1SEL0 |= BIT7;
    P1SEL1 |= BIT7;
    // Configure reference module
    PMMCTL0_H = PMMPW_H; // Unlock the PMM registers
    PMMCTL2 = INTREFEN | REFVSEL_2 | EXTREFEN; // Enable internal 2.5V reference

    while(!(PMMCTL2 & REFGENRDY)); // Poll till internal reference settles

    ADCMCTL0 = ADCINCH_7 | ADCSREF_0; // A1 ADC input select = OA0 output
    // Vref = DVCC

    如果配置ADC/DAC的内部参考电压是可以的，我仅仅是将1.7引脚配置输出2.5V是失败的，也通过ADC通道的选择

    非常感谢你的回答

  • 0 回复 Susan Yang
    Intellectual 580 points
    是不是只能输出1.2V 不能输出2.5V 我看的是这么说的
  • 0 回复 user5707170
    TI__Guru**** 252096 points
    是的 1.2 V for external reference (VREF pin)
  • 0
    Guru 67475 points

    msp430内部的2.5v基准电压，可以在内部使用，但不能输出。