在STM32上直接使用ODR寄存器 [英] Using the ODR register directly On STM32

问题描述

修改WriteLED()的代码以直接使用ODR寄存器.该代码应读取当前 寄存器的值，然后写回修改的值，具体取决于要点亮的LED 开启或关闭.

Modify the code for WriteLED() to use the ODR register directly. The code should read the current value of the register and then write back a modified value depending on what LEDs are to be turns on or off.

提供给我的示例代码

void HAL_GPIO_TogglePin(GPIO_TypeDef* GPIOx, uint16_t GPIO_Pin)
{
/* Check the parameters */
assert_param(IS_GPIO_PIN(GPIO_Pin));
GPIOx->ODR ˆ= GPIO_Pin;
}

需要更改的代码

WriteLED (uint8_t LED, uint8_t State)
{
  // Check for correct state
 if ((State != LED_OFF) && (State != LED_ON))
  {
    return;
  }

  // Turn on/off the LED
  switch (LED)
    {
    case 'L':
      HAL_GPIO_WritePin (LD4_GPIO_Port, LD4_Pin, State);
      break;
    case 'T':
      HAL_GPIO_WritePin (LD3_GPIO_Port, LD3_Pin, State);
      break;
    case 'B':
      HAL_GPIO_WritePin (LD6_GPIO_Port, LD6_Pin, State);
      break;
    case 'R':
      HAL_GPIO_WritePin (LD5_GPIO_Port, LD5_Pin, State);
      break;
    }

  return;
}

以上代码在输出到ODR寄存器时应该是什么样子

What should the above code look like when outputting to ODR register

推荐答案

您需要了解C按位运算.这三个是^(异或)，&(按位与)，|(按位或)

You need to understand C bitwise operations. The three are ^ (exclusive OR), & (bitwise and), | (bitwise or)

要清除一点 GPIO->ODR &= ~pin_mask;

要设置一点 GPIO->ODR |= pin_mask;

这应该为您提供足够的信息.

This should give you enough information.

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