I don't know why STM32F427 I2C3 will send the byte repeat?

[yongjie989]

Posted on March 04, 2016 at 17:38

Hi all,

Are there have any one know this problem, I have to trying send only one byte via I2C3, butI don't know why STM32F427 I2C3 will send the byte repeat? uint32_t I2C_WrBuf(I2C_TypeDef* I2Cx, uint8_t DevAddr, uint8_t *buf, uint32_t cnt) {    I2Cx->CR1 |= I2C_CR1_START;  I2Cx->DR = (DevAddr << 1) | I2C_Direction_Transmitter;    I2Cx->DR = 0x30;             /* Here is very simple to send one byte */  I2Cx->CR1 |= I2C_CR1_STOP;Below is I2C3 config.    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA , ENABLE);    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC , ENABLE);    GPIO_PinAFConfig(GPIOA, GPIO_PinSource8, GPIO_AF_I2C3);    GPIO_PinAFConfig(GPIOC, GPIO_PinSource9, GPIO_AF_I2C3);    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;    GPIO_InitStructure.GPIO_OType = GPIO_OType_OD;    GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_UP;    GPIO_Init(GPIOA, &GPIO_InitStructure);    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;    GPIO_Init(GPIOC, &GPIO_InitStructure);    RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C3, ENABLE);    RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C3, ENABLE);    RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C3, DISABLE);    I2C_InitStructure.I2C_Mode = I2C_Mode_I2C;    I2C_InitStructure.I2C_DutyCycle = I2C_DutyCycle_2;    I2C_InitStructure.I2C_OwnAddress1 = 0x00;     I2C_InitStructure.I2C_Ack = I2C_Ack_Enable;    I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;    I2C_InitStructure.I2C_ClockSpeed = 50000;     I2C_Init(I2Cx, &I2C_InitStructure);    I2C_Cmd(I2Cx, ENABLE); #stm32f427 #i2c3

[Tesla DeLorean]

Posted on March 04, 2016 at 18:55

Wouldn't you need to wait for the register to free up before jamming in the next value?

[yongjie989]

Posted on March 05, 2016 at 07:58I have try to wait, but still show same result. But if I use I2C1, I2C1 is no this issue.