I am using the STM32F30x_DSP_StdPeriph_Lib_V1.2.3 library following instructions given in stm32f30x_12c.c for the initilization:
#define I2C_SHORT_TIMEOUT ((uint32_t)0x1000)
#define I2C_LONG_TIMEOUT ((uint32_t) (10 * I2C_SHORT_TIMEOUT))
#define I2Cx_RCC RCC_APB1Periph_I2C1
#define I2Cx I2C1
#define I2C_GPIO_RCC RCC_AHBPeriph_GPIOB
#define I2C_GPIO GPIOB
#define I2C_PIN_SDA GPIO_Pin_7
#define I2C_PIN_SCL GPIO_Pin_6
#define I2C_AF GPIO_AF_4
//#define SLAVE_ADDRESS 0x08
static uint32_t i2cTimeout;
void I2C_LowLevel_Init(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
/* Configure the I2C clock source. The clock is derived from the SYSCLK */
RCC_I2CCLKConfig(RCC_I2C1CLK_SYSCLK);
/* I2C_SCL_GPIO_CLK and I2C_SDA_GPIO_CLK Periph clock enable */
RCC_AHBPeriphClockCmd(I2C_GPIO_RCC, ENABLE);
/* I2C Periph clock enable */
RCC_APB1PeriphClockCmd(I2Cx_RCC, ENABLE);
GPIO_PinAFConfig(I2C_GPIO, I2C_PIN_SCL, I2C_AF);
/* Connect PXx to I2C_SDA*/
GPIO_PinAFConfig(I2C_GPIO, I2C_PIN_SDA, I2C_AF);
/* GPIO configuration */
/* Configure I2C MEMS pins: SCL */
GPIO_InitStructure.GPIO_Pin = I2C_PIN_SCL | I2C_PIN_SDA;
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_NOPULL; // External Pull Up
GPIO_Init(I2C_GPIO, &GPIO_InitStructure);
}
void i2c_init()
{
I2C_InitTypeDef I2C_InitStructure;
I2C_LowLevel_Init();
/*!< I2C configuration */
/* sEE_I2C configuration */
I2C_InitStructure.I2C_Mode = I2C_Mode_I2C;
I2C_InitStructure.I2C_AnalogFilter = I2C_AnalogFilter_Enable;
I2C_InitStructure.I2C_DigitalFilter = 0x01;
I2C_InitStructure.I2C_OwnAddress1 = 0x00;
I2C_InitStructure.I2C_Ack = I2C_Ack_Enable;
I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;
I2C_InitStructure.I2C_Timing = 0x50330309; // 0x50330309 400 KHz, use 0xC062121F for 100KHz
/* MEMS_I2C Peripheral Enable */
I2C_Cmd(I2Cx, ENABLE);
/* Apply MEMS_I2C configuration after enabling it */
I2C_Init(I2Cx, &I2C_InitStructure);
/* NVIC Configuration */
// NVIC_Config();
/*!< Select the EEPROM address */
MEMS_Address = 0x68;
}
I am using I2C1 with PB6 & PB7, AF4 and address 0x68
Later, when I try to read a register using the following code:
uint8_t i2c_read(I2C_TypeDef* i2cx, uint8_t address, uint8_t reg, uint8_t len, uint8_t* buf)
{
address <<= 1;
/* Test on BUSY Flag */
i2cTimeout = I2C_LONG_TIMEOUT;
while (I2C_GetFlagStatus(i2cx, I2C_ISR_BUSY) != RESET) {
if ((i2cTimeout--) == 0) {
return i2cTimeoutUserCallback();
}
}
/* Configure slave address, nbytes, reload, end mode and start or stop generation */
I2C_TransferHandling(i2cx, address, 1, I2C_SoftEnd_Mode, I2C_Generate_Start_Write);
/* Wait until TXIS flag is set */
i2cTimeout = I2C_LONG_TIMEOUT;
while (I2C_GetFlagStatus(i2cx, I2C_ISR_TXIS) == RESET) { // was I2C_ISR_TXIS
if ((i2cTimeout--) == 0) {
return i2cTimeoutUserCallback();
}
}
/* Send Register address */
I2C_SendData(i2cx, (uint8_t) reg);
/* Wait until TC flag is set */
i2cTimeout = I2C_LONG_TIMEOUT;
while (I2C_GetFlagStatus(i2cx, I2C_ISR_TC) == RESET) { // was I2C_ISR_TC
if ((i2cTimeout--) == 0) {
return i2cTimeoutUserCallback();
}
}
/* Configure slave address, nbytes, reload, end mode and start or stop generation */
I2C_TransferHandling(i2cx, address, len, I2C_AutoEnd_Mode, I2C_Generate_Start_Read);
/* Wait until all data are received */
while (len) {
/* Wait until RXNE flag is set */
i2cTimeout = I2C_LONG_TIMEOUT;
while (I2C_GetFlagStatus(i2cx, I2C_ISR_RXNE) == RESET) {
if ((i2cTimeout--) == 0) {
return i2cTimeoutUserCallback();
}
}
/* Read data from RXDR */
*buf = I2C_ReceiveData(i2cx);
/* Point to the next location where the byte read will be saved */
buf++;
/* Decrement the read bytes counter */
len--;
}
/* Wait until STOPF flag is set */
i2cTimeout = I2C_LONG_TIMEOUT;
while (I2C_GetFlagStatus(i2cx, I2C_ISR_STOPF) == RESET) {
if ((i2cTimeout--) == 0) {
return i2cTimeoutUserCallback();
}
}
/* Clear STOPF flag */
I2C_ClearFlag(i2cx, I2C_ICR_STOPCF);
/* If all operations OK */
return 1;
}
It times out sfter the asttempt to send a start sequence.
I've tried everything!! I made sure that the bits are actually the ones I'm physically using, Initializing andd setting first PB6 then PB7 to "0". They have pull up resistors so I made sure I could pull them down.
I have a digital analyzer on the I2C buss, and during the sequence to start both line remain high.
Don't know what else to try. On an STM32F10x had no problem... but of course the code and configuration is different.
