发表于
2008-8-9 16:30:00
/*******************************************************************************
* 函数名称: I2C_DeInit
* 功能描述: 将I2Cx外设寄存器复位到它们的默认值.
* 输入参数: I2Cx：x可为1或2来选择I2C外设.
* 输出参数: 无
* 返回参数: 无
*******************************************************************************/
void I2C_DeInit(I2C_TypeDef* I2Cx)
{
/* Check the parameters [检查参数]*/
assert_param(IS_I2C_ALL_PERIPH(I2Cx));
switch (*(u32*)&I2Cx)
{
case I2C1_BASE:
/* Enable I2C1 reset state [允许I2C1复位状态]*/
RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C1, ENABLE);
/* Release I2C1 from reset state [解除I2C1复位状态]*/
RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C1, DISABLE);
break;
case I2C2_BASE:
/* Enable I2C2 reset state [允许I2C2复位状态]*/
RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C2, ENABLE);
/* Release I2C2 from reset state [解除I2C2复位状态]*/
RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C2, DISABLE);
break;
default:
break;
}
}
/*******************************************************************************
* 函数名称: I2C_Init
* 功能描述: 按照I2C_InitStruct的特定参数初始化I2C部件.
* 输入参数: (1)I2Cx：x可为1或2来选择I2C部件.
* (2)I2C_InitStruct：指向I2C_InitTypeDef结构，该结构包含了特定I2C部件的配置信息。
* 输出参数: 无
* 返回参数: 无
******************************************************************************/
void I2C_Init(I2C_TypeDef* I2Cx, I2C_InitTypeDef* I2C_InitStruct)
{
u16 tmpreg = 0, freqrange = 0;
u16 result = 0x04;
u32 pclk1 = 8000000;
RCC_ClocksTypeDef rcc_clocks;
/* Check the parameters [检查参数]*/
assert_param(IS_I2C_ALL_PERIPH(I2Cx));
assert_param(IS_I2C_MODE(I2C_InitStruct->I2C_Mode));
assert_param(IS_I2C_DUTY_CYCLE(I2C_InitStruct->I2C_DutyCycle));
assert_param(IS_I2C_OWN_ADDRESS1(I2C_InitStruct->I2C_OwnAddress1));
assert_param(IS_I2C_ACK_STATE(I2C_InitStruct->I2C_Ack));
assert_param(IS_I2C_ACKNOWLEDGE_ADDRESS(I2C_InitStruct->I2C_AcknowledgedAddress));
assert_param(IS_I2C_CLOCK_SPEED(I2C_InitStruct->I2C_ClockSpeed));
/*---------------------------- I2Cx CR2 Configuration ------------------------*/
/* Get the I2Cx CR2 value */
tmpreg = I2Cx->CR2;
/* Clear frequency FREQ[5:0] bits */
tmpreg &= CR2_FREQ_Reset;
/* Get pclk1 frequency value */
RCC_GetClocksFreq(&rcc_clocks);
pclk1 = rcc_clocks.PCLK1_Frequency;
/* Set frequency bits depending on pclk1 value */
freqrange = (u16)(pclk1 / 1000000);
tmpreg |= freqrange;
/* Write to I2Cx CR2 */
I2Cx->CR2 = tmpreg;
/*---------------------------- I2Cx CCR Configuration ------------------------*/
/* Disable the selected I2C peripheral to configure TRISE */
I2Cx->CR1 &= CR1_PE_Reset;
/* Reset tmpreg value */
/* Clear F/S, DUTY and CCR[11:0] bits */
tmpreg = 0;
/* Configure speed in standard mode */
if (I2C_InitStruct->I2C_ClockSpeed <= 100000)
{
/* Standard mode speed calculate */
result = (u16)(pclk1 / (I2C_InitStruct->I2C_ClockSpeed << 1));
/* Test if CCR value is under 0x4*/
if (result < 0x04)
{
/* Set minimum allowed value */
result = 0x04;
}
/* Set speed value for standard mode */
tmpreg |= result;
/* Set Maximum Rise Time for standard mode */
I2Cx->TRISE = freqrange + 1;
}
/* Configure speed in fast mode */
else /*(I2C_InitStruct->I2C_ClockSpeed <= 400000)*/
{
if (I2C_InitStruct->I2C_DutyCycle == I2C_DutyCycle_2)
{
/* Fast mode speed calculate: Tlow/Thigh = 2 */
result = (u16)(pclk1 / (I2C_InitStruct->I2C_ClockSpeed * 3));
}
else /*I2C_InitStruct->I2C_DutyCycle == I2C_DutyCycle_16_9*/
{
/* Fast mode speed calculate: Tlow/Thigh = 16/9 */
result = (u16)(pclk1 / (I2C_InitStruct->I2C_ClockSpeed * 25));
/* Set DUTY bit */
result |= I2C_DutyCycle_16_9;
}
/* Test if CCR value is under 0x1*/
if ((result & CCR_CCR_Set) == 0)
{
/* Set minimum allowed value */
result |= (u16)0x0001;
}
/* Set speed value and set F/S bit for fast mode */
tmpreg |= result | CCR_FS_Set;
/* Set Maximum Rise Time for fast mode */
I2Cx->TRISE = (u16)(((freqrange * 300) / 1000) + 1);
}
/* Write to I2Cx CCR */
I2Cx->CCR = tmpreg;
/* Enable the selected I2C peripheral */
I2Cx->CR1 |= CR1_PE_Set;
/*---------------------------- I2Cx CR1 Configuration ------------------------*/
/* Get the I2Cx CR1 value */
tmpreg = I2Cx->CR1;
/* Clear ACK, SMBTYPE and SMBUS bits */
tmpreg &= CR1_CLEAR_Mask;
/* Configure I2Cx: mode and acknowledgement */
/* Set SMBTYPE and SMBUS bits according to I2C_Mode value */
/* Set ACK bit according to I2C_Ack value */
tmpreg |= (u16)((u32)I2C_InitStruct->I2C_Mode | I2C_InitStruct->I2C_Ack);
/* Write to I2Cx CR1 */
I2Cx->CR1 = tmpreg;
/*---------------------------- I2Cx OAR1 Configuration -----------------------*/
/* Set I2Cx Own Address1 and acknowledged address */
I2Cx->OAR1 = (I2C_InitStruct->I2C_AcknowledgedAddress | I2C_InitStruct->I2C_OwnAddress1);
}
完整stm32f10x_i2c.c
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