I2C. address is not transmitted after START condition
Hi, I'm trying to write i2c ISR by myself with LL. But after START condition address don't transfer(I see it in my oscilloscope), although I write to I2C1->DR address of slave and read reference manual with attention for proper handling.
I generate initialization code with CubeMX, so there should not be errors in this part.
Here's my code of freertos task:
oid i2cLCD(void *arg) { // just FreeRTOS task
while (1) {
// wait for button to be pressed
xEventGroupWaitBits(btnE, BUTTON_TASK_BIT, pdTRUE, pdTRUE, portMAX_DELAY);
//enable i2c event interrupt
LL_I2C_EnableIT_EVT(I2C1);
// generate start condition
LL_I2C_GenerateStartCondition(I2C1);
//wait for transfer to complete
xEventGroupWaitBits(btnE, I2C_TASK_BIT, pdTRUE, pdTRUE, portMAX_DELAY);
i2c_data = i2c_data ^ 0xff;
}
}Here's code of ISR:
void I2C1_EV_IRQHandler(void)
{
static BaseType_t wake = pdFALSE;
if (I2C1->SR1 & I2C_SR1_SB) {
I2C1->DR = 0x4e; //address of pcf8574
return;
}
if (LL_I2C_IsActiveFlag_ADDR(I2C1)) {
LL_I2C_TransmitData8(I2C1, 0xff);
LL_I2C_ClearFlag_ADDR(I2C1);
return;
}
if (LL_I2C_IsActiveFlag_BTF(I2C1)) {
LL_I2C_GenerateStopCondition(I2C1);
xEventGroupSetBitsFromISR(btnE, I2C_TASK_BIT, &wake);
return;
}
}As I said, on SCL line I see falling edge and no pulses. On SDA nothing occurs - high level remains. I tried debugging - interrupt really occurs and condition on 5th line of code passes and 6th line executes. After that interrupt don't want to fire anymore and address just doesn't get transmitted. Maybe somebody encountered this kind of error? I'm trying to follow reference manual precisely, but can't get result. Thank you in advance!