驱动I2C操作研究
typedef struct
{
uint32 id; 设备逻辑ID
uint32 freq; 频率
uint32 bus; 总线，这里不用理会，自动分配
uint8 slave_addr; 从设备地址
uint8 reg_addr_num; IIC内部寄存器长度
uint8 check_ack; 应答信号，１检查 ０不检查
uint8 no_stop; 停止位
} I2C_DEV;
API
I2C_HAL_OPEN :初始化I2C设备控制器，并返回从设备句柄，必须要调用I2C_HAL_Close来释放。
参数：dev: I2C从设备指针
返回值：大于等于０ 成功返回句柄
小于０ 出错
I2C_HAL_CLOSE :关闭I2C控制器
参数：Handle: 已初始化的I2C handle
返回值：成功 0
失败 -1
I2C_HAL_Read :I2C控制器读数据
参数：Handle : 已初始化的I2C handle
reg_addr ：从设备寄存器地址
buffer ：从从设备里读取的数据保存在buffer里
bytes ：读多少位
返回值：成功 返回读取的数量
失败 0
I2C_HAL_Write :I2C控制器写数据
参数：Handle : 已初始化的I2C handle
reg_addr ：从设备寄存器地址
buffer ：往从设备里写保存在buffer里的数据
bytes ：写多少位
返回值：成功 返回写的数量
失败 0
I2C_HAL_Ioctl :设备读取I2C控制器状态
参数：Handle : 已初始化的I2C handle
cmd ：i2c_drvapi.h里定义的命令
arg ：命令参数
返回值：没有返回值
API 例子
操作一个8位寄存器设备
1写
[开始][从设备地址][写][应答][设备寄存器地址7:0][应答][数据][应答][停止]
2读
[开始][从设备地址][写][应答][设备寄存器地址7:0][应答][重复起始][设备寄存器地址7:0][读][读到的数据][非应答][停止]
sample code
#include "i2c_drvapi.h"
/*define the i2c slave device handle*/
uint32 i2c_handle_device;
void i2c_device_init(void)
{
……
/*init i2c*/
I2C_DEV dev;
dev.id = 0; //this i2c slave device is connected to i2c bus 0.
dev.freq = 100*1000; //100KHz
dev.slave_addr = 0x60; //8-bit write address
dev.reg_addr_num = 1; // i2c slave device register’s length is 8-bits
dev.check_ack = 1; //check ack signal
dev.no_stop = 0; //send stop
i2c_handle_device = I2C_HAL_Open(&dev);
/*other init process*/
……
}
uint32 device_set_some_para (void)
{
……
uint8 addr = 0x30; //register address
uint8 buffer = 0x10; //data buffer
I2C_HAL_Write(i2c_handle_device, &addr, &buffer, 1);
……
}
uint32 device_get_some_para (void)
{
……
uint8 addr = 0x30; //register address
uint8 buffer = 0; //data buffer
I2C_HAL_Read(i2c_handle_device, &addr, &buffer, 1);
……
}
void i2c_device_exit(void)
{
……
I2C_HAL_Close(i2c_handle_device);
……
}
操作一个16位寄存器设备
1写
[开始][从设备地址][写][应答][从设备寄存器(15:8)][应答][设备寄存器地址7:0][应答][数据][应答][停止]
2读
[开始][从设备地址][写][应答][从设备寄存器(15:8)][应答][设备寄存器地址7:0][应答][重复起始][从设备地址][读][读到的数据][非应答][停止]
sample code
#include "i2c_drvapi.h"
/*define the i2c slave device handle*/
uint32 i2c_handle_device;
void i2c_device_init(void)
{
……
/*init i2c*/
I2C_DEV dev;
dev.id = 0; //this i2c slave device is connected to i2c bus 0.
dev.freq = 100*1000; //100KHz
dev.slave_addr = 0x30; //8-bit write address
dev.reg_addr_num = 2; // i2c slave device register’s length is 16-bits
dev.check_ack = 1; //check ack signal
dev.no_stop = 0; //send stop
i2c_handle_device = I2C_HAL_Open(&dev);
/*other init process*/
……
}
uint32 device_set_some_para (void)
{
……
uint8 addr[2] = {0}; //register address
uint8 buffer[2] = {0}; //data buffer
addr[0] = 0x30; //high 8 bits of the register address
addr[1] = 0x90; //low 8 bits of the register address
buffer[0] = 0x10; //high 8 bits of the data value
buffer[1] = 0x20; //low 8 bits of the data value
I2C_HAL_Write(i2c_handle_device, addr, buffer, 2);
……
}
uint32 device_get_some_para (void)
{
……
uint8 addr[2] = {0}; //register address
uint8 buffer[2] = {0}; //data buffer
addr[0] = 0x30; //high 8 bits of the register address
addr[1] = 0x90; //low 8 bits of the register address
I2C_HAL_Read(i2c_handle_device, addr, buffer, 2);
……
}
void i2c_device_exit(void)
{
……
I2C_HAL_Close(i2c_handle_device);
……
}
-----------------------------多设备
#include "i2c_drvapi.h"
/*define the i2c slave device handle*/
uint32 i2c_handle_device;
void i2c_device_init(void)
{
……
/*init i2c*/
I2C_DEV dev;
dev.id = 1; //this i2c slave device is connected to i2c bus 1.
dev.freq = 100*1000; //100KHz
dev.slave_addr = 0x2c; //8-bit write address
dev.reg_addr_num = 0; // i2c slave device is simple
dev.check_ack = 1; //check ack signal
dev.no_stop = 0; //send stop
i2c_handle_device = I2C_HAL_Open(&dev);
/*other init process*/
……
}
uint32 device_set_some_para (void)
{
……
uint8 buffer[2] = {0}; //data buffer
buffer[0] = 0x10; //high 8 bits of the data value
buffer[1] = 0x20; //low 8 bits of the data value
I2C_HAL_Write(i2c_handle_device, NULL, buffer, 2);
……
}
uint32 device_get_some_para (void)
{
……
uint8 buffer[2] = {0}; //data buffer
I2C_HAL_Read(i2c_handle_device, NULL, buffer, 2);
……
}
void i2c_device_exit(void)
{
……
I2C_HAL_Close(i2c_handle_device);
……
}
----------------------------------------------
APPLICATION EXAMPLE
PUBLIC ERR_I2C_E PCM1774_WriteRegister(uint8 reg_addr,uint8 data)
{
uint8 cmd[2];
cmd[0] = reg_addr;
cmd[1] = data;
return I2C_WriteCmdArr(PCM1774_ADDRESS_WR, cmd, 2, SCI_TRUE);
}
