[Linux项目实践] 物联网单板测试：LPC11C14 IIC_Init

I2CInit

IIC初始化步骤：

1、复位外设：LPC_SYSCON->PRESETCTRL |= (0x1<<1);

2、时钟使能：LPC_SYSCON->SYSAHBCLKCTRL |= (1<<5);

3、定义GPIO管脚，选择IIC功能管脚SCL、SDA：

LPC_IOCON->PIO0_4 &= ~0x3F; /* I2C I/O config */

LPC_IOCON->PIO0_4 |= 0x01; /* I2C SCL */

LPC_IOCON->PIO0_5 &= ~0x3F;

LPC_IOCON->PIO0_5 |= 0x01; /* I2C SDA */

4、清空IIC寄存器

LPC_I2C->CONCLR = I2CONCLR_AAC | I2CONCLR_SIC | I2CONCLR_STAC | I2CONCLR_I2ENC;

5、设置高低电平寄存器

LPC_I2C->SCLL

LPC_I2C->SCLH

6、设置从地址寄存器

7、中断使能

NVIC_EnableIRQ(I2C_IRQn);

8、接口使能

LPC_I2C->CONSET = I2CONSET_I2EN;

具体步骤完成如下：

1、 IIC复位外设

LPC_SYSCON->PRESETCTRL |= (0x1<<1);

LPC_SYSCON：系统控制

#define LPC_SYSCON ((LPC_SYSCON_TypeDef *) LPC_SYSCON_BASE)

#define LPC_SYSCON_BASE (LPC_APB0_BASE + 0x48000) //APB外设系统控制地址

#define LPC_APB0_BASE (0x40000000UL) //APB外设在系统中的地址



1.1、外设复位控制，复位取消

LPC_SYSCON->PRESETCTRL |= (0x1<<1); //IIC复位取消





LPC_SYSCON_TypeDef->PRESETCTRL //默认值

__IO uint32_t PRESETCTRL; /*!< Offset: 0x004 Peripheral reset control (R/W) */

2、使能IIC时钟(AHBCLKCTRL寄存器控制系统和外设寄存器接口的时钟使能)

LPC_SYSCON->SYSAHBCLKCTRL |= (1<<5);





#define LPC_SYSCON ((LPC_SYSCON_TypeDef *) LPC_SYSCON_BASE)

__IO uint32_t SYSAHBCLKCTRL; /*!< Offset: 0x080 System AHB clock control (R/W) */

3、定义GPIO管脚，选择IIC功能管脚SCL、SDA

#define LPC_IOCON ((LPC_IOCON_TypeDef *) LPC_IOCON_BASE )

#define LPC_IOCON_BASE (LPC_APB0_BASE + 0x44000)

#define LPC_APB0_BASE (0x40000000UL)



3.1、LPC_IOCON->PIO0_4 &= ~0x3F; /* I2C I/O config [5:0]=0*/

3.2、LPC_IOCON->PIO0_4 |= 0x01; /* I2C SCL */

__IO uint32_t PIO0_4; /*!< Offset: 0x030 I/O configuration for pin PIO0_4/SCL (R/W) */









3.3、LPC_IOCON->PIO0_5 &= ~0x3F; /* I2C I/O config [5:0]=0*/

3.4、LPC_IOCON->PIO0_5 |= 0x01; /* I2C SDA */





4、清空IIC寄存器

4.1、#define LPC_I2C ((LPC_I2C_TypeDef *) LPC_I2C_BASE)

#define LPC_I2C_BASE (LPC_APB0_BASE + 0x00000)

#define LPC_APB0_BASE (0x40000000UL)



/*--- Clear flags ---*/

I2CONCLR寄存器控制对I2CON寄存器中的位的清零，这些位控制I2C接口的操作。向该寄存器写入1会清零寄存器中对应的位，向这个寄存器中写入0无效

LPC_I2C->CONCLR = I2CONCLR_AAC | I2CONCLR_SIC | I2CONCLR_STAC | I2CONCLR_I2ENC;

__O uint32_t CONCLR; /*!< Offset: 0x018 I2C Control Clear Register ( /W) */

#define I2CONCLR_AAC 0x00000004 /*[2:0]=0000 0100*/ /* I2C Control clear Register */

#define I2CONCLR_SIC 0x00000008 /*[3:0]=0000 1000*/

#define I2CONCLR_STAC 0x00000020 /*[5:0]=0010 0000*/

#define I2CONCLR_I2ENC 0x00000040 /*[6:0]=0100 0000*/











5、设定IIC时钟高低电平时间比

#if FAST_MODE_PLUS

5.1、LPC_IOCON->PIO0_4 |= (0x1<<9);

5.2、LPC_IOCON->PIO0_5 |= (0x1<<9);



5.1、LPC_I2C->SCLL = I2SCLL_HS_SCLL; // IIC时钟的低电平时间

5.2、LPC_I2C->SCLH = I2SCLH_HS_SCLH; //IIC时钟的高电平时

__IO uint32_t SCLH; /*!< Offset: 0x010 SCH Duty Cycle Register High Half Word (R/W) */

__IO uint32_t SCLL; /*!< Offset: 0x014 SCL Duty Cycle Register Low Half Word (R/W) */



#define I2SCLH_HS_SCLH 0x00000020 /* Fast Plus I2C SCL Duty Cycle High Reg */

#define I2SCLL_HS_SCLL 0x00000020 /* Fast Plus I2C SCL Duty Cycle Low Reg */

#else

5.3、LPC_I2C->SCLL = I2SCLL_SCLL;

5.4、LPC_I2C->SCLH = I2SCLH_SCLH;

#endif

#define I2SCLH_SCLH 0x00000180 /* I2C SCL Duty Cycle High Reg */

#define I2SCLL_SCLL 0x00000180 /* I2C SCL Duty Cycle Low Reg */

6、设置从地址寄存器

if ( I2cMode == I2CSL***E )

{

LPC_I2C->ADR0 = slaveAddr;

}

#define I2CSL***E 0x02

__IO uint32_t ADR0; /*!< Offset: 0x00C I2C Slave Address Register 0 (R/W) */









7、IIC中断使能

/* Enable the I2C Interrupt */

NVIC_EnableIRQ(I2C_IRQn);

/**

* @brief Enable Interrupt in NVIC Interrupt Controller

* @param IRQn The positive number of the external interrupt to enable

* Enable a device specific interupt in the NVIC interrupt controller.

* The interrupt number cannot be a negative value.

*/

static __INLINE void NVIC_EnableIRQ(IRQn_Type IRQn)

{

NVIC->ISER[0] = (1 << ((uint32_t)(IRQn) & 0x1F)); /* enable interrupt */

}

#define NVIC ((NVIC_Type *) NVIC_BASE) /*!< NVIC configuration struct */

#define NVIC_BASE (SCS_BASE + 0x0100) /*!< NVIC Base Address */

#define SCS_BASE (0xE000E000) /*!< System Control Space Base Address */



8、IIC接口使能

LPC_I2C->CONSET = I2CONSET_I2EN;

#define LPC_I2C ((LPC_I2C_TypeDef *) LPC_I2C_BASE)

__IO uint32_t CONSET; /*!< Offset: 0x000 I2C Control Set Register (R/W) */



#define I2CONSET_I2EN 0x00000040 /*[6:0]=0100 0000*/ /* I2C Control Set Register */