diff --git a/README.md b/README.md
index 96a63bb..775f699 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,51 @@
 # zh_avr_i2c
 
 AVR library for I2C bus.
+
+#include "avr/io.h"
+#include "stdio.h"
+#include "zh_avr_i2c.h"
+
+#define BAUD_RATE 9600
+#define BAUD_PRESCALE (F_CPU / 16 / BAUD_RATE - 1)
+
+int usart(char byte, FILE *stream)
+{
+	while ((UCSR0A & (1 << UDRE0)) == 0)
+	{
+	}
+	UDR0 = byte;
+	return 0;
+}
+FILE uart = FDEV_SETUP_STREAM(usart, NULL, _FDEV_SETUP_WRITE);
+
+void i2c_example_task(void *pvParameters)
+{
+	zh_avr_i2c_master_init(false);
+	avr_err_t err = zh_avr_i2c_master_probe(0x38, 100 / portTICK_PERIOD_MS);
+	switch (err)
+	{
+	case AVR_OK:
+		printf("Slave Answered.\n");
+		break;
+	case AVR_ERR_INVALID_RESPONSE:
+		printf("Slave Not Answer.\n");
+		break;
+	default:
+		printf("Bus Error.\n");
+		break;
+	}
+	vTaskDelete(NULL);
+}
+
+int main(void)
+{
+	UBRR0H = (BAUD_PRESCALE >> 8);
+	UBRR0L = BAUD_PRESCALE;
+	UCSR0B = (1 << RXEN0) | (1 << TXEN0);
+	UCSR0C = (1 << UCSZ01) | (1 << UCSZ00);
+	stdout = &uart;
+	xTaskCreate(i2c_example_task, "i2c example task", configMINIMAL_STACK_SIZE, NULL, tskIDLE_PRIORITY, NULL);
+	vTaskStartScheduler();
+	return 0;
+}
\ No newline at end of file
diff --git a/zh_avr_i2c.c b/zh_avr_i2c.c
index 0471eed..3b0974c 100644
--- a/zh_avr_i2c.c
+++ b/zh_avr_i2c.c
@@ -11,7 +11,7 @@
 #define I2C_COLLISION 0x04
 #define I2C_BUS_FAIL 0x08
 
-#define TWCR_START ((1 << TWINT) | (1 << TWEN) | (1 << TWIE))
+#define I2C_START ((1 << TWINT) | (1 << TWEN) | (1 << TWIE))
 #define I2C_MASTER_READ 1
 #define I2C_MASTER_WRITE 0
 
@@ -47,7 +47,7 @@ avr_err_t zh_avr_i2c_master_probe(const uint8_t addr, TickType_t xTicksToWait)
 {
 	_work_mode = MASTER_PR;
 	_target_i2c_address = addr;
-	TWCR = TWCR_START | (1 << TWSTA);
+	TWCR = I2C_START | (1 << TWSTA);
 	EventBits_t bits = xEventGroupWaitBits(_event_group_handle, I2C_OK | I2C_NACK | I2C_COLLISION | I2C_BUS_FAIL, pdTRUE, pdFALSE, xTicksToWait);
 	if (bits & I2C_OK)
 	{
@@ -106,12 +106,13 @@ uint8_t WorkIndex = 0; // Индекс лога
 
 ISR(TWI_vect) // Прерывание TWI Тут наше все.
 {
+	BaseType_t xHigherPriorityTaskWoken = pdFALSE;
 	switch (TWSR & 0xF8) // Отсекаем биты прескалера
 	{
 	case 0x00: // Bus error.
 		printf("00\n");
-		TWCR = TWCR_START | (1 << TWSTO);
-		xEventGroupSetBitsFromISR(_event_group_handle, I2C_BUS_FAIL, NULL);
+		TWCR = I2C_START | (1 << TWSTO);
+		xEventGroupSetBitsFromISR(_event_group_handle, I2C_BUS_FAIL, &xHigherPriorityTaskWoken);
 		break;
 	case 0x08: // A START condition has been transmitted.
 		printf("08\n");
@@ -125,7 +126,7 @@ ISR(TWI_vect) // Прерывание TWI Тут наше все.
 			break;
 		case MASTER_PR:
 			TWDR = (_target_i2c_address << 1) | I2C_MASTER_READ;
-			TWCR = TWCR_START;
+			TWCR = I2C_START;
 			break;
 		default:
 			break;
@@ -133,7 +134,7 @@ ISR(TWI_vect) // Прерывание TWI Тут наше все.
 		break;
 	case 0x10: // A repeated START condition has been transmitted.
 		printf("10\n");
-		TWCR = TWCR_START | (1 << TWSTO);
+		TWCR = I2C_START | (1 << TWSTO);
 		break;
 	case 0x18: // SLA+W has been transmitted. ACK has been received.
 		printf("18\n");
@@ -149,6 +150,8 @@ ISR(TWI_vect) // Прерывание TWI Тут наше все.
 		break;
 	case 0x38: // Arbitration lost in SLA+W or data bytes. Arbitration lost in SLA+R or NOT ACK bit.
 		printf("38\n");
+		TWCR = I2C_START | (1 << TWSTO);
+		xEventGroupSetBitsFromISR(_event_group_handle, I2C_COLLISION, &xHigherPriorityTaskWoken);
 		break;
 	case 0x40: // SLA+R has been transmitted. ACK has been received.
 		printf("40\n");
@@ -161,8 +164,8 @@ ISR(TWI_vect) // Прерывание TWI Тут наше все.
 		case MASTER_TX_RX:
 			break;
 		case MASTER_PR:
-			TWCR = TWCR_START | (1 << TWSTO);
-			xEventGroupSetBitsFromISR(_event_group_handle, I2C_OK, NULL);
+			TWCR = I2C_START | (1 << TWSTO);
+			xEventGroupSetBitsFromISR(_event_group_handle, I2C_OK, &xHigherPriorityTaskWoken);
 			break;
 		default:
 			break;
@@ -170,21 +173,8 @@ ISR(TWI_vect) // Прерывание TWI Тут наше все.
 		break;
 	case 0x48: // SLA+R has been transmitted. NOT ACK has been received.
 		printf("48\n");
-		switch (_work_mode)
-		{
-		case MASTER_TX:
-			break;
-		case MASTER_RX:
-			break;
-		case MASTER_TX_RX:
-			break;
-		case MASTER_PR:
-			TWCR = TWCR_START | (1 << TWSTO);
-			xEventGroupSetBitsFromISR(_event_group_handle, I2C_NACK, NULL);
-			break;
-		default:
-			break;
-		}
+		TWCR = I2C_START | (1 << TWSTO);
+		xEventGroupSetBitsFromISR(_event_group_handle, I2C_NACK, &xHigherPriorityTaskWoken);
 		break;
 	case 0x50: // Data byte has been received. ACK has been returned.
 		printf("50\n");
@@ -681,6 +671,10 @@ ISR(TWI_vect) // Прерывание TWI Тут наше все.
 	default:
 		break;
 	}
+	if (xHigherPriorityTaskWoken == pdTRUE)
+	{
+		portYIELD();
+	};
 }
 
 void DoNothing(void) // Функция пустышка, затыкать несуществующие ссылки