stm32专题三：位带操作—GPIO输出和输入

位带操作其实很简单，就是把位带区某寄存器的特定位，用公式给映射到位带别名区的32位地址上，该地址在编译器看来是个立即数，因此需要强制类型转换成32位地址指针，最后对指针取值操作。

特别值得注意的是，在强制类型转换成地址时，一定要加volatile关键词，不然一定会被编译器level-3优化掉，导致程序出错。博主一开始是直接使用(unsigned int *)，然后在这里调试了很久，一直没发现问题所在，突然想到三级优化，加上volatile后程序正常执行。

以下是位带宏定义和输入—输出测试代码，

#include "stm32f10x.h"

#include "bsp_led.h"

#include "bsp_key.h"

/** 

  * @brief 位带操作

  * @cal   ((addr & 0xF0000000) + 0X02000000 + ((addr & 0x00FFFFFF) << 5) + ((bitnum) << 2))

  * @note  上述公式将位带区的寄存器addr第bitnum位，转化为位带别名区的一个32位地址

  * @attention 强制类型时一定要加volatile，不然会被level-3优化掉（ODR正常，IDR错误）

  */

// 位带输出

#define GPIOA_ODR_Addr (GPIOA_BASE + 0X0C)

#define GPIOB_ODR_Addr (GPIOB_BASE + 0X0C)

#define GPIOC_ODR_Addr (GPIOC_BASE + 0X0C)

#define GPIOD_ODR_Addr (GPIOD_BASE + 0X0C)

#define GPIOE_ODR_Addr (GPIOE_BASE + 0X0C)

#define GPIOF_ODR_Addr (GPIOF_BASE + 0X0C)

#define GPIOG_ODR_Addr (GPIOG_BASE + 0X0C)

#define PAout(n) *(volatile unsigned int *)((GPIOA_ODR_Addr & 0xF0000000) + 0X02000000 + ((GPIOA_ODR_Addr & 0x00FFFFFF) << 5) + ((n) << 2))

#define PBout(n) *(volatile unsigned int *)((GPIOB_ODR_Addr & 0xF0000000) + 0X02000000 + ((GPIOB_ODR_Addr & 0x00FFFFFF) << 5) + ((n) << 2))

#define PCout(n) *(volatile unsigned int *)((GPIOC_ODR_Addr & 0xF0000000) + 0X02000000 + ((GPIOC_ODR_Addr & 0x00FFFFFF) << 5) + ((n) << 2)) 

#define PDout(n) *(volatile unsigned int *)((GPIOD_ODR_Addr & 0xF0000000) + 0X02000000 + ((GPIOD_ODR_Addr & 0x00FFFFFF) << 5) + ((n) << 2))

#define PEout(n) *(volatile unsigned int *)((GPIOE_ODR_Addr & 0xF0000000) + 0X02000000 + ((GPIOE_ODR_Addr & 0x00FFFFFF) << 5) + ((n) << 2))

#define PFout(n) *(volatile unsigned int *)((GPIOF_ODR_Addr & 0xF0000000) + 0X02000000 + ((GPIOF_ODR_Addr & 0x00FFFFFF) << 5) + ((n) << 2))

#define PGout(n) *(volatile unsigned int *)((GPIOG_ODR_Addr & 0xF0000000) + 0X02000000 + ((GPIOG_ODR_Addr & 0x00FFFFFF) << 5) + ((n) << 2))

// 位带输入

#define GPIOA_IDR_Addr (GPIOA_BASE + 0X08)

#define GPIOB_IDR_Addr (GPIOB_BASE + 0X08)

#define GPIOC_IDR_Addr (GPIOC_BASE + 0X08)

#define GPIOD_IDR_Addr (GPIOD_BASE + 0X08)

#define GPIOE_IDR_Addr (GPIOE_BASE + 0X08)

#define GPIOF_IDR_Addr (GPIOF_BASE + 0X08)

#define GPIOG_IDR_Addr (GPIOG_BASE + 0X08)

#define PAin(n) *(volatile unsigned int *)((GPIOA_IDR_Addr & 0xF0000000) + 0X02000000 + ((GPIOA_IDR_Addr & 0x00FFFFFF) << 5) + ((n) << 2))

#define PBin(n) *(volatile unsigned int *)((GPIOB_IDR_Addr & 0xF0000000) + 0X02000000 + ((GPIOB_IDR_Addr & 0x00FFFFFF) << 5) + ((n) << 2))

#define PCin(n) *(volatile unsigned int *)((GPIOC_IDR_Addr & 0xF0000000) + 0X02000000 + ((GPIOC_IDR_Addr & 0x00FFFFFF) << 5) + ((n) << 2))

#define PDin(n) *(volatile unsigned int *)((GPIOD_IDR_Addr & 0xF0000000) + 0X02000000 + ((GPIOD_IDR_Addr & 0x00FFFFFF) << 5) + ((n) << 2))

#define PEin(n) *(volatile unsigned int *)((GPIOE_IDR_Addr & 0xF0000000) + 0X02000000 + ((GPIOE_IDR_Addr & 0x00FFFFFF) << 5) + ((n) << 2))

#define PFin(n) *(volatile unsigned int *)((GPIOF_IDR_Addr & 0xF0000000) + 0X02000000 + ((GPIOF_IDR_Addr & 0x00FFFFFF) << 5) + ((n) << 2))

#define PGin(n) *(volatile unsigned int *)((GPIOG_IDR_Addr & 0xF0000000) + 0X02000000 + ((GPIOG_IDR_Addr & 0x00FFFFFF) << 5) + ((n) << 2))

void delay(uint32_t count);

int main(void)

{

LED_GPIO_Config();

KEY_GPIO_Config();

#if 0

while (1)

{

// 位带输出测试

PBout(1) = 1;

delay(0XFFFFF);

PBout(1) = 0;

delay(0XFFFFF);

}

#else

while (1)

{

// 位带输入测试

if (PAin(0) == KEY_ON)

{

while (PAin(0) == KEY_ON);

LED_B_OFF;

LED_R_TOGGLE;

}

if (PCin(13) == KEY_ON)

{

while (PCin(13) == KEY_ON);

LED_R_OFF;

LED_B_TOGGLE;

}

}

#endif

}

void delay(uint32_t count)

{

for (; count != 0; count--);

}