diff --git a/modbus.c b/modbus.c
index 8af3c24..48981ca 100644
--- a/modbus.c
+++ b/modbus.c
@@ -25,6 +25,8 @@ static uint16_t dev_id = DEFAULT_DEVICE_MODBUS_ID;
 const uint16_t com_dev_id = 247;
 
 static void (*ModbusUartSendByte)(USART_TypeDef*, unsigned char);
+static void (*ModbusTimEnable)(TIM_TypeDef*);
+static void (*ModbusTimDisable)(TIM_TypeDef*);
 static int32_t (*ModbusTcpSendByte)(uint8_t, unsigned char*, uint16_t);
 static void (*ModbusRIRPoll)(void);
 static void (*ModbusRHRPoll)(void);
@@ -34,6 +36,12 @@ static void (*ModbusWSRPoll)(uint16_t, uint16_t);
 void modbus_connect_callback_send_byte(void (*s)(USART_TypeDef*, unsigned char)) {
     ModbusUartSendByte = s;
 }
+void modbus_connect_callback_tim_en(void (*s)(TIM_TypeDef*)) {
+    ModbusTimEnable = s;
+}
+void modbus_connect_callback_tim_dis(void (*s)(TIM_TypeDef*)) {
+    ModbusTimDisable = s;
+}
 #endif
 
 #ifdef CURRENT_OPERATION_MODE_TCP
@@ -388,29 +396,19 @@ void modbus_poll(void) {
 }
 //======================= UART HANDLERS =========================//
 #ifdef CURRENT_OPERATION_MODE_UART
-void Modbus_UART_IRQHandler(void) {
-    if (USART_GetITStatus(Modbus_UART, USART_IT_RXNE) != RESET) {
-        while(USART_GetFlagStatus(Modbus_UART,USART_FLAG_RXNE) == RESET) {}
-        if (rx_buf_ptr < 128) {
-            rx_buf[rx_buf_ptr++] = (unsigned char)Modbus_UART -> DR;
-        } else {
-            Modbus_UART -> DR;
-        }
-        USART_ClearITPendingBit(Modbus_UART, USART_IT_RXNE);
-        
-        if (timer_state == 0) {
-            timer_state = 1;
-            Modbus_TIM -> CNT = 0;
-            TIM_Cmd(Modbus_TIM, ENABLE);
-        }
+void Modbus_GetByte(unsigned char byte) {
+    if (rx_buf_ptr < 128) {
+        rx_buf[rx_buf_ptr++] = byte;
+    }
+    
+    if (timer_state == 0) {
+        timer_state = 1;
+        ModbusTimEnable(Modbus_TIM);
     }
 }
 
-void Modbus_TIM_IRQHandler(void) {
-    if (TIM_GetITStatus(Modbus_TIM, TIM_IT_Update) != RESET)
-        TIM_ClearITPendingBit(Modbus_TIM, TIM_IT_Update);
-    
-    TIM_Cmd(Modbus_TIM, DISABLE);
+void Modbus_TIM_Handler(void) {
+    ModbusTimDisable(Modbus_TIM);
     timer_state = 0;
     rx_flag = 1;
 }
diff --git a/modbus.h b/modbus.h
index faac8bd..51f98a1 100644
--- a/modbus.h
+++ b/modbus.h
@@ -28,10 +28,14 @@ void set_modbus_id(unsigned char);
 
 
 void modbus_connect_callback_send_byte(void (*s)(USART_TypeDef*, unsigned char));
+void modbus_connect_callback_tim_en(void (*s)(TIM_TypeDef*));
+void modbus_connect_callback_tim_dis(void (*s)(TIM_TypeDef*));
 void modbus_connect_callback_send_buf_tcp(int32_t (*s)(uint8_t, unsigned char*, uint16_t));
 void modbus_connect_callback_rir_poll(void (*s)(void));
 void modbus_connect_callback_rhr_poll(void (*s)(void));
 void modbus_connect_callback_wsr_poll(void (*s)(uint16_t, uint16_t));
+void Modbus_GetByte(unsigned char);
+void Modbus_TIM_Handler(void);
 void modbus_poll(void);
 void modbus_reset(void);
 
diff --git a/modbus_constants_example.h b/modbus_constants_example.h
index 85d0ecf..d87279e 100644
--- a/modbus_constants_example.h
+++ b/modbus_constants_example.h
@@ -6,28 +6,28 @@
 
 // MCU Includes
 
+#include "stm32f4xx_ll_lptim.h"
 #include "stm32f4xx_ll_gpio.h"
+#include "stm32f4xx_ll_tim.h"
 
 
 // Needed Constants
 
 #define DEFAULT_DEVICE_MODBUS_ID        1
-#define CURRENT_OPERATION_MODE_TCP
+#define CURRENT_OPERATION_MODE_UART
 
 #define Modbus_LED                  GPIOB
-#define Modbus_LED_Pin              LL_GPIO_PIN_9
+#define Modbus_LED_Pin              LL_GPIO_PIN_2
 #define MODBUS_LED_ON               LL_GPIO_SetOutputPin(Modbus_LED, Modbus_LED_Pin);
 #define MODBUS_LED_OFF              LL_GPIO_ResetOutputPin(Modbus_LED, Modbus_LED_Pin);
 
 #ifdef CURRENT_OPERATION_MODE_UART
-    #define RS485_GPIO                  GPIOB
-    #define RS485_GPIO_Pin              GPIO_Pin_6
-    #define MODBUS_TX_EN                GPIO_WriteBit(RS485_GPIO, RS485_GPIO_Pin, Bit_SET);
-    #define MODBUS_TX_DIS               GPIO_WriteBit(RS485_GPIO, RS485_GPIO_Pin, Bit_RESET);
-    #define Modbus_UART                 USART2
+    #define MODBUS_TX_EN                LL_GPIO_SetOutputPin(RS485_GPIO, RS485_GPIO_Pin);
+    #define MODBUS_TX_DIS               LL_GPIO_ResetOutputPin(RS485_GPIO, RS485_GPIO_Pin);
+    #define RS485_GPIO                  GPIOA
+    #define RS485_GPIO_Pin              LL_GPIO_PIN_11
+    #define Modbus_UART                 USART1
     #define Modbus_TIM                  TIM2
-    #define Modbus_UART_IRQHandler      USART2_IRQHandler
-    #define Modbus_TIM_IRQHandler       TIM2_IRQHandler
 #endif