我正在浏览文档，并将指出一些您可能遗漏的细节。您能否提供LED的当前行为？是否只有一种颜色被激活（红色，绿色，蓝色）变亮，没有颜色被激活或RGB组件之间的混合被激活？

1. P1.1和P1.4都需要使能上拉电阻

转到schematics of the launchpad并查找与微控制器的按钮连接，我们可以在**图29原理图（2/6）**中看到，连接到P1.1和P1.4的按钮都接地：

• Button topology in the board schematics的

因此，应根据MSP432P4xx SimpleLink™ Microcontrollers Technical Reference Manual第12.2.4节的表12.1在两个I/O处启用上拉电阻：

• Table 12.1 of MSP432P4xx SimpleLink™ Microcontrollers Technical Reference Manual的

按钮接地且存在上拉电阻器的这种拓扑的结果是负逻辑：如果按钮被按下，则输入接地，因此MCU读取0;如果按钮未被按下，则输入经由上拉电阻器从VCC获得信号，因此MCU读取1;总之：按下按钮= 0，打开按钮= 1。

2.无需为LED输出启用电阻

回到图29中的schematics of the launchpad，在那里我们可以看到连接到P2.0的LED，P2.1和P2.2已经在阳极中有一个电阻，我不认为需要有上拉或下拉电阻。没有电阻你应该很好：

• LED topology in the board schematics
  3.您可能需要在输出端口启用高驱动强度

由于LED以共阴极方式排列，因此MSP 432 I/O引脚将需要驱动电流以点亮LED（与共阳极配置中发生的情况相反）。因此，您需要激活引脚P2.0的高强度驱动器，P2.1和P2.2。再次回到MSP432P4xx SimpleLink™ Microcontrollers Technical Reference Manual，在第**12.2.5节输出驱动强度选择寄存器（PxDS）**中，我们可以看到需要设置BIT 0，P2 DS寄存器中的BIT 1和BIT 2，以允许它们使用高强度IO驱动程序

TheMulittle做了一个很好的帖子解释了很多。我将给予3个代码示例如何使用按钮

按下按钮时打开LED

// This program will turn off a red LED when a button is pressed

#include "msp.h"
#include <stdint.h>

int main(void) {
  // configure P1.0 and P1.1 as GPIO
  P1->SEL0 &= ~0x03;
  P1->SEL1 &= ~0x03;

  // set P1.0 as output and P1.1 as input
  P1->DIR |= 0x1;  // set P1.0 as output
  P1->DIR &= ~0x2; // set P1.1 as input

  // enable pull-up/pull-down resistors for P1.1
  P1->REN |= 0x2;

  // enable pull-up resistor for P1.1
  P1->OUT |= 0x2;

  while (1) {
    // check if the button connected to P1.1 is pressed
    if ((P1->IN & 0x2) == 0x2) {
      // if the button is not pressed, turn on the red LED connected to P1.0
      P1->OUT |= 0x1;
    } else {
      // if the button is pressed, turn off the red LED connected to P1.0
      P1->OUT &= ~0x1;
    }
  }
}

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按下按钮时关闭LED

// This program will turn off a red LED when a button is pressed

#include "msp.h"
#include <stdint.h>

int main(void) {
  // configure P1.0 and P1.1 as GPIO
  P1->SEL0 &= ~(BIT0 | BIT1);
  P1->SEL1 &= ~(BIT0 | BIT1);

  // set P1.0 as output and P1.1 as input
  P1->DIR |= BIT0;  // set P1.0 as output
  P1->DIR &= ~BIT1; // set P1.1 as input

  // enable pull-up/pull-down resistors for P1.1
  P1->REN |= BIT1;

  // enable pull-up resistor for P1.1
  P1->OUT |= BIT1;

  while (1) {
    // check if the button connected to P1.1 is pressed
    if ((P1->IN & BIT1) == BIT1) {
      // if the button is not pressed, turn on the red LED connected to P1.0
      P1->OUT |= BIT0;
    } else {
      // if the button is pressed, turn off the red LED connected to P1.0
      P1->OUT &= ~BIT0;
    }
  }
}

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检测按钮按下（也是一个很酷的uart功能）

void uart_init(void) {
  EUSCI_A0->CTLW0 |= 0X1;
  EUSCI_A0->MCTLW  = 0X0;
  EUSCI_A0->CTLW0 |= 0x80;
  EUSCI_A0->BRW    = 0x34;
  EUSCI_A0->CTLW0 &= ~0x01;
  P1->SEL0        |= 0x0C;
  P1->SEL1        &= ~0x0C;
}

void uart_send_str(const char *str) {
  uint32_t i = 0;
  while (str[i] != '\0') {
    EUSCI_A0->TXBUF = str[i];
    while ((EUSCI_A0->IFG & 0x02) == 0) {}
    i++;
  }
}

// Use the other code examples with this function:
void digital_input(void) {
  bool button1 = (P1->IN & BIT1) == 0;
  bool button2 = (P1->IN & BIT4) == 0;
  if (button1 && button2) {
    uart_send_str("Buttons 1 and 2 are pressed\r\n");
  } else if (button1) {
    uart_send_str("Buttons 1 is pressed\r\n");
  } else if (button2) {
    uart_send_str("Button 2 is pressed\r\n");
  } else {
    uart_send_str("No Buttons are pressed\r\n");
  }
}

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