diff --git a/left/build/kds/.project b/left/build/kds/.project
index 7129608..9b30aed 100644
--- a/left/build/kds/.project
+++ b/left/build/kds/.project
@@ -71,6 +71,16 @@
 			<type>1</type>
 			<locationURI>PARENT-3-PROJECT_LOC/lib/KSDK_2.0_MKL03Z8xxx4/devices/MKL03Z4/drivers/fsl_gpio.h</locationURI>
 		</link>
+		<link>
+			<name>drivers/fsl_i2c.c</name>
+			<type>1</type>
+			<locationURI>PARENT-3-PROJECT_LOC/lib/KSDK_2.0_MKL03Z8xxx4/devices/MKL03Z4/drivers/fsl_i2c.c</locationURI>
+		</link>
+		<link>
+			<name>drivers/fsl_i2c.h</name>
+			<type>1</type>
+			<locationURI>PARENT-3-PROJECT_LOC/lib/KSDK_2.0_MKL03Z8xxx4/devices/MKL03Z4/drivers/fsl_i2c.h</locationURI>
+		</link>
 		<link>
 			<name>drivers/fsl_port.h</name>
 			<type>1</type>
diff --git a/left/src/i2c.h b/left/src/i2c.h
new file mode 100644
index 0000000..4d34f7c
--- /dev/null
+++ b/left/src/i2c.h
@@ -0,0 +1,19 @@
+#ifndef __I2C_H__
+#define __I2C_H__
+
+// Macros:
+
+    #define I2C_BUS_BASEADDR  I2C0
+    #define I2C_BUS_CLK_SRC   I2C0_CLK_SRC
+    #define I2C_BUS_BAUD_RATE 100000 // 100 kHz works even with a 20 meter long bridge cable.
+    #define I2C_BUS_MUX       kPORT_MuxAlt2
+
+    #define I2C_BUS_SDA_PORT  PORTB
+    #define I2C_BUS_SDA_CLOCK kCLOCK_PortB
+    #define I2C_BUS_SDA_PIN   4
+
+    #define I2C_BUS_SCL_PORT  PORTB
+    #define I2C_BUS_SCL_CLOCK kCLOCK_PortB
+    #define I2C_BUS_SCL_PIN   3
+
+#endif
diff --git a/left/src/init_peripherials.c b/left/src/init_peripherials.c
new file mode 100644
index 0000000..bcfaa6e
--- /dev/null
+++ b/left/src/init_peripherials.c
@@ -0,0 +1,36 @@
+#include "fsl_common.h"
+#include "fsl_port.h"
+#include "test_led.h"
+#include "i2c_addresses.h"
+#include "fsl_i2c.h"
+#include "fsl_clock.h"
+#include "i2c.h"
+
+void InitI2c() {
+    port_pin_config_t pinConfig = {
+        .pullSelect = kPORT_PullUp,
+    };
+
+    i2c_master_config_t masterConfig;
+    I2C_MasterGetDefaultConfig(&masterConfig);
+    uint32_t sourceClock;
+
+    // Initialize main bus
+
+    CLOCK_EnableClock(I2C_BUS_SDA_CLOCK);
+    CLOCK_EnableClock(I2C_BUS_SCL_CLOCK);
+
+    pinConfig.mux = I2C_BUS_MUX;
+    PORT_SetPinConfig(I2C_BUS_SDA_PORT, I2C_BUS_SDA_PIN, &pinConfig);
+    PORT_SetPinConfig(I2C_BUS_SCL_PORT, I2C_BUS_SCL_PIN, &pinConfig);
+
+    masterConfig.baudRate_Bps = I2C_BUS_BAUD_RATE;
+    sourceClock = CLOCK_GetFreq(I2C_BUS_CLK_SRC);
+    I2C_MasterInit(I2C_BUS_BASEADDR, &masterConfig, sourceClock);
+}
+
+void InitPeripherials(void)
+{
+    InitTestLed();
+    InitI2c();
+}
diff --git a/left/src/init_peripherials.h b/left/src/init_peripherials.h
new file mode 100644
index 0000000..bb75a64
--- /dev/null
+++ b/left/src/init_peripherials.h
@@ -0,0 +1,8 @@
+#ifndef __INIT_H__
+#define __INIT_H__
+
+// Functions:
+
+    void InitPeripherials();
+
+#endif
diff --git a/left/src/main.c b/left/src/main.c
index 6d31a7a..a6f489d 100644
--- a/left/src/main.c
+++ b/left/src/main.c
@@ -1,8 +1,12 @@
 #include "fsl_gpio.h"
 #include "init_clock.h"
 #include "fsl_port.h"
+#include "fsl_i2c.h"
 #include "key_matrix.h"
 #include "test_led.h"
+#include "i2c_addresses.h"
+#include "i2c.h"
+#include "init_peripherials.h"
 
 #define KEYBOARD_MATRIX_COLS_NUM 7
 #define KEYBOARD_MATRIX_ROWS_NUM 5
@@ -28,13 +32,51 @@ key_matrix_t keyMatrix = {
     }
 };
 
+i2c_slave_config_t slaveConfig;
+i2c_slave_handle_t slaveHandle;
+volatile bool g_SlaveCompletionFlag = false;
+
+static void i2c_slave_callback(I2C_Type *base, i2c_slave_transfer_t *xfer, void *userData)
+{
+    switch (xfer->event)
+    {
+        case kI2C_SlaveTransmitEvent:
+            xfer->data = keyMatrix.keyStates;
+            xfer->dataSize = KEYBOARD_MATRIX_COLS_NUM*KEYBOARD_MATRIX_ROWS_NUM;
+            break;
+        case kI2C_SlaveReceiveEvent:
+            break;
+        case kI2C_SlaveCompletionEvent:
+            g_SlaveCompletionFlag = true;
+            break;
+        case kI2C_SlaveTransmitAckEvent:
+            break;
+        default:
+            g_SlaveCompletionFlag = true;
+            break;
+    }
+}
+
 int main(void)
 {
-    InitTestLed();
     InitClock();
+    InitPeripherials();
 
+    I2C_SlaveGetDefaultConfig(&slaveConfig);
+    slaveConfig.slaveAddress = I2C_ADDRESS_LEFT_KEYBOARD_HALF;
+    slaveConfig.addressingMode = kI2C_Address7bit/kI2C_RangeMatch;
+    I2C_SlaveInit(I2C_BUS_BASEADDR, &slaveConfig);
+    I2C_SlaveTransferCreateHandle(I2C_BUS_BASEADDR, &slaveHandle, i2c_slave_callback, NULL);
+    I2C_SlaveTransferNonBlocking(I2C_BUS_BASEADDR, &slaveHandle, kI2C_SlaveCompletionEvent);
+
+//    while (!g_SlaveCompletionFlag) {}
+//    g_SlaveCompletionFlag = false;
+
+    TEST_LED_OFF();
     KeyMatrix_Init(&keyMatrix);
-    KeyMatrix_Scan(&keyMatrix);
+    while (1) {
+        KeyMatrix_Scan(&keyMatrix);
+    }
 
     while (1)
     {
@@ -48,48 +90,6 @@ int main(void)
 }
 
 /*
-#define I2C_DATA_LENGTH 2
-
-#include "board.h"
-#include "fsl_clock_manager.h"
-#include "fsl_i2c_slave_driver.h"
-#include "fsl_i2c_shared_function.h"
-#include "i2c_addresses.h"
-#include "main.h"
-
-uint8_t isSw2Pressed;
-uint8_t isSw3Pressed;
-uint8_t buffer[I2C_DATA_LENGTH];
-
-void I2C0_IRQHandler(void)
-{
-    I2C_DRV_IRQHandler(I2C0_IDX);
-}
-
-static void i2c_slave_callback(uint8_t instance, i2c_slave_event_t i2cEvent, void *param)
-{
-    i2c_slave_state_t *slaveState = I2C_DRV_SlaveGetHandler(instance);
-
-    switch (i2cEvent) {
-        case kI2CSlaveTxReq:
-            slaveState->txSize = I2C_DATA_LENGTH;
-            slaveState ->txBuff = buffer;
-            slaveState ->isTxBusy = true;
-            buffer[0] = isSw2Pressed;
-            buffer[1] = isSw3Pressed;
-            break;
-
-        case kI2CSlaveTxEmpty:
-            slaveState->isTxBusy = false;
-            break;
-
-        default:
-            break;
-    }
-}
-
-int main(void)
-{
     // Initialize GPIO.
 
     gpio_input_pin_user_config_t inputPin[] =
@@ -157,5 +157,4 @@ int main(void)
         GPIO_DRV_WritePinOutput(kGpioLED1, isSw2Pressed);
         GPIO_DRV_WritePinOutput(kGpioLED3, isSw3Pressed);
     }
-}
 */
diff --git a/right/src/usb_interface_keyboard.c b/right/src/usb_interface_keyboard.c
index 13db19c..799379d 100644
--- a/right/src/usb_interface_keyboard.c
+++ b/right/src/usb_interface_keyboard.c
@@ -3,6 +3,9 @@
 #include "usb_composite_device.h"
 #include "test_led.h"
 #include "key_matrix.h"
+#include "fsl_i2c.h"
+#include "i2c.h"
+#include "i2c_addresses.h"
 
 static usb_device_endpoint_struct_t UsbKeyboardEndpoints[USB_KEYBOARD_ENDPOINT_COUNT] = {{
     USB_KEYBOARD_ENDPOINT_INDEX | (USB_IN << USB_DESCRIPTOR_ENDPOINT_ADDRESS_DIRECTION_SHIFT),
@@ -62,6 +65,9 @@ key_matrix_t keyMatrix = {
     }
 };
 
+#define KEY_STATE_COUNT (5*7)
+uint8_t leftKeyStates[KEY_STATE_COUNT] = {0};
+
 static usb_status_t UsbKeyboardAction(void)
 {
     UsbKeyboardReport.modifiers = 0;
@@ -75,6 +81,16 @@ static usb_status_t UsbKeyboardAction(void)
         UsbKeyboardReport.scancodes[scancodeIdx] = 0;
     }
 
+    i2c_master_transfer_t masterXfer;
+    masterXfer.slaveAddress = I2C_ADDRESS_LEFT_KEYBOARD_HALF;
+    masterXfer.direction = kI2C_Read;
+    masterXfer.subaddress = 0;
+    masterXfer.subaddressSize = 0;
+    masterXfer.data = leftKeyStates;
+    masterXfer.dataSize = KEY_STATE_COUNT;
+    masterXfer.flags = kI2C_TransferDefaultFlag;
+    I2C_MasterTransferBlocking(I2C_MAIN_BUS_BASEADDR, &masterXfer);
+
     scancodeIdx = 0;
     for (uint8_t keyId=0; keyId<KEYBOARD_MATRIX_COLS_NUM*KEYBOARD_MATRIX_ROWS_NUM; keyId++) {
         if (keyMatrix.keyStates[keyId] && scancodeIdx<USB_KEYBOARD_MAX_KEYS) {
@@ -82,6 +98,12 @@ static usb_status_t UsbKeyboardAction(void)
         }
     }
 
+    for (uint8_t keyId=0; keyId<KEY_STATE_COUNT; keyId++) {
+        if (leftKeyStates[keyId] && scancodeIdx<USB_KEYBOARD_MAX_KEYS) {
+            UsbKeyboardReport.scancodes[scancodeIdx++] = keyId + HID_KEYBOARD_SC_A;
+        }
+    }
+
     return USB_DeviceHidSend(UsbCompositeDevice.keyboardHandle, USB_KEYBOARD_ENDPOINT_INDEX,
                              (uint8_t*)&UsbKeyboardReport, USB_KEYBOARD_REPORT_LENGTH);
 }