case    TIC_STATE_POS_STOP:
            I2C2->CR1 = I2C_CR1_PE | I2C_CR1_STOP;
            tic_state = TIC_STATE_FILL_START;
            break;

        case    TIC_STATE_FILL_START:
            s1 = 0;
            while(I2C2->SR1 !=0 ) s1++;
            I2C2->CR1 = I2C_CR1_PE | I2C_CR1_START;
            tic_state = TIC_STATE_FILL;
            break;

#define TUNER_ADDR_NATIVE_SEQ 0x10 //RDA5807 mode, sequential register address
#define TUNER_ADDR_NATIVE_RND 0x11 //RDA5807 mode, random access mode.
#define TUNER_ADDR_COMPATIBLE 0x60 //TEA5767 compatible mode
#define FRAM_ADDR             0x53 //адрес FRAM-памяти FM31T37x
#define RTC_ADDR              0x6B //адрес RTC FM31T37x
#define TSC_ADDR              0x41 //адрес touchscreen controller STMPE811

enum {OPTION_DUPLEX_RS, OPTION_DUPLEX_SS, OPTION_2BYTE, OPTION_TIMER, OPTION_SA};
..
extern "C" void Isr()
{
u32 i0 = i2cU->SR[0], i1;
if (!i0) return;
switch (isrStep) {
case IS_RESTART: //передан повторный START
if (!(i0 &= ~(1 << SR0_BTF | 1 << SR0_TXE))) return;
case IS_START: //передан START
if (i0 != 1 << SR0_SB) fault(i0);
i0 = i2cU->SR[1];
if ((i0 & (1 << SR1_MSL | 1 << SR1_BUSY | 1 << SR1_TRA)) !=
(1 << SR1_MSL | 1 << SR1_BUSY)) fault(i0 | ERR_BAD_START << 16);
if (saddr & 1)
if (cnt + 1 < 0) i2cU->CR[0] = 1 << CR0_ENA | 1 << CR0_ACK;
i2cU->DR = saddr;
if (option & 1 << OPTION_TIMER) actTimer = HrTimerGet();
isrStep = IS_SADDR;
return;
case IS_SADDR: //передан Slave Address
...
case IS_CMD1: //передана вся стартовая последовательность
if (i0 == 1 << SR0_TXE) return;
if (i0 != (1 << SR0_BTF | 1 << SR0_TXE)) fault(i0);
if (option & (1 << OPTION_DUPLEX_SS | 1 << OPTION_DUPLEX_RS)) {
saddr++;
i2cU->CR[0] = (option >> OPTION_DUPLEX_SS & 1) << CR0_STOP |
1 << CR0_START | 1 << CR0_ENA;
isrStep = IS_RESTART;
return;
} else if (cnt) {
i1 = IS_TX;
...

// HW_ExchangeTransmitData - функция отправки данных по внешнему каналу обмена.
// Параметры:
// Buffer - указатель на буфер передаваемых данных;
// Size - объем данных в байтах.
// Возвращаемое значение:
// HW_EXCHANGE_TRANSMIT_OK - отправка успешно запущена;
// HW_EXCHANGE_TRANSMIT_ERROR_TIMEOUT - канал обмена занят транзакцией данных.
unsigned int HW_ExchangeTransmitData(void *Buffer, unsigned int Size)
{
HW_EXCHANGE_TIMER_START(65535);

while(I2C_GetFlagStatus(I2C1, I2C_FLAG_BUSY) && !ExchangeBusyStatus);
HW_EXCHANGE_TIMER_STOP();

unsigned int PhysicalBusy = ExchangeBusyStatus;
ExchangeBusyStatus = 0;

if(PhysicalBusy)
return HW_EXCHANGE_TRANSMIT_ERROR_TIMEOUT;
else
{
ExchangeTxDataQuantity = Size;

DMA_MemoryTargetConfig(DMA1_Stream6, (unsigned int)Buffer, DMA_Memory_0);
DMA_SetCurrDataCounter(DMA1_Stream6, ExchangeTxDataQuantity);

I2C_GenerateSTART(I2C1, ENABLE);

HW_EXCHANGE_TIMER_START(1);

return HW_EXCHANGE_TRANSMIT_OK;
}
}

void I2C1_EV_IRQHandler(void)
{
if(I2C_GetITStatus(I2C1, I2C_IT_SB) == SET)
{
ExchangeDirection = HW_EXCHANGE_DIRECTION_TRANSMITTER;

HW_EXCHANGE_TIMER_STOP();

I2C_Send7bitAddress(I2C1, HW_EXCHANGE_I2C_ADDRESS_ABONENT, I2C_Direction_Transmitter);

HW_EXCHANGE_TIMER_START(1);

return;
}

if(ExchangeDirection == HW_EXCHANGE_DIRECTION_RECEIVER)
{
BaseType_t xHigherPriorityTaskWoken = pdFALSE;

if(I2C_GetITStatus(I2C1, I2C_IT_ADDR) == SET)
{
if(!ExchangeOverrunStatus)
{
ExchangeOverrunStatus = 1;

DMA_MemoryTargetConfig(DMA1_Stream0, ExchangeRxDataBuffer, DMA_Memory_0);
DMA_SetCurrDataCounter(DMA1_Stream0, ExchangeRxBufferSize);

DMA_ClearFlag(DMA1_Stream0, DMA_FLAG_TCIF0);

DMA_Cmd(DMA1_Stream0, ENABLE);
}
else
System.ExchangeStatus |= SYSTEM_EXCHANGE_STATUS_RX_ERROR_DATA_OVERRUN;

(void)I2C_GetFlagStatus(I2C1, I2C_FLAG_TRA);
}

if(I2C_GetITStatus(I2C1, I2C_IT_BTF) == SET)
{
(void)I2C_ReceiveData(I2C1);

System.ExchangeStatus |= SYSTEM_EXCHANGE_STATUS_RX_ERROR_BUFFER_OVERFLOW;
}

if(I2C_GetITStatus(I2C1, I2C_IT_STOPF) == SET)
{
if(DMA_GetCmdStatus(DMA1_Stream0) == ENABLE)
DMA_Cmd(DMA1_Stream0, DISABLE);

if(I2C_GetFlagStatus(I2C1, I2C_FLAG_RXNE) == SET)
{
(void)I2C_ReceiveData(I2C1);

System.ExchangeStatus |= SYSTEM_EXCHANGE_STATUS_RX_ERROR_BUFFER_OVERFLOW;
}

*ExchangeRxDataQuantity = ExchangeRxBufferSize - DMA_GetCurrDataCounter(DMA1_Stream0);

xSemaphoreGiveFromISR(ExchangeRxSemaphoreHandle, &xHigherPriorityTaskWoken);

I2C_GenerateSTOP(I2C1, DISABLE);
}

portYIELD_FROM_ISR(xHigherPriorityTaskWoken);
}
else
{
BaseType_t xHigherPriorityTaskWoken = pdFALSE;

if(I2C_GetITStatus(I2C1, I2C_IT_ADDR) == SET)
{
HW_EXCHANGE_TIMER_STOP();

DMA_ClearFlag(DMA1_Stream6, DMA_FLAG_TCIF6);

DMA_Cmd(DMA1_Stream6, ENABLE);

(void)I2C_GetFlagStatus(I2C1, I2C_FLAG_TRA);

HW_EXCHANGE_TIMER_START(ExchangeTxDataQuantity + 1);
}
else if(I2C_GetITStatus(I2C1, I2C_IT_BTF) == SET)
{
HW_EXCHANGE_TIMER_STOP();

I2C_GenerateSTOP(I2C1, ENABLE);

ExchangeDirection = HW_EXCHANGE_DIRECTION_RECEIVER;

xSemaphoreGiveFromISR(ExchangeTxSemaphoreHandle, &xHigherPriorityTaskWoken);
}

portYIELD_FROM_ISR(xHigherPriorityTaskWoken);
}
}

while(ожидание флага);