diff --git a/CMakeLists.txt b/CMakeLists.txt
index 87ed163..60c5a22 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -49,6 +49,7 @@ set(TARGET_SOURCES
     "src/app_gpio.c"
     "src/app_reg_if.c"
     "src/app_sys_utils.c"
+    "src/app_uart.c"
     "src/main.c"
 )
 
diff --git a/include/app_uart.h b/include/app_uart.h
new file mode 100644
index 0000000..d3cc79e
--- /dev/null
+++ b/include/app_uart.h
@@ -0,0 +1,10 @@
+#ifndef APP_UART_H
+#define APP_UART_H
+
+#include "fsl_common_arm.h"
+
+void     app_uart_init(void);
+uint16_t app_uart_module_reg_read(uint8_t addr);
+void     app_uart_module_reg_write(uint8_t addr, uint16_t data);
+
+#endif  // APP_UART_H
diff --git a/src/app_reg_if.c b/src/app_reg_if.c
index a2b3655..e0b1ad1 100644
--- a/src/app_reg_if.c
+++ b/src/app_reg_if.c
@@ -3,6 +3,7 @@
 #include "app_dac.h"
 #include "app_gpio.h"
 #include "app_sys_utils.h"
+#include "app_uart.h"
 
 /* Private */
 #include "app_reg_if.h"
@@ -11,7 +12,8 @@
 #define MODULE_ID_GPIO      1
 #define MODULE_ID_ADC       2
 #define MODULE_ID_DAC       3
-#define MODULE_ID_END       4
+#define MODULE_ID_UART      4
+#define MODULE_ID_END       5
 
 typedef uint16_t (*module_reg_read_t)(uint8_t offset);
 typedef void (*module_reg_write_t)(uint8_t offset, uint16_t data);
@@ -42,6 +44,11 @@ static const module_reg_t s_module_regs[MODULE_ID_END] = {
             .read  = app_dac_module_reg_read,
             .write = app_dac_module_reg_write,
         },
+    [MODULE_ID_UART] =
+        {
+            .read  = app_uart_module_reg_read,
+            .write = app_uart_module_reg_write,
+        },
 };
 
 uint16_t app_reg_if_read(uint8_t reg) {
diff --git a/src/app_sys_utils.c b/src/app_sys_utils.c
index 6328ea0..65ae1f3 100644
--- a/src/app_sys_utils.c
+++ b/src/app_sys_utils.c
@@ -13,13 +13,27 @@
 #define APP_SYS_CONST_ID  (0xEACEU)
 #define APP_SYS_CONST_VER (0x0000U)
 
+#define APP_SYS_CFG_GPIO0_FUNC_Pos (0U)
+#define APP_SYS_CFG_GPIO0_FUNC_Msk (3U << APP_SYS_CFG_GPIO0_FUNC_Pos)
+
+#define APP_SYS_CFG_GPIO1_FUNC_Pos (2U)
+#define APP_SYS_CFG_GPIO1_FUNC_Msk (3U << APP_SYS_CFG_GPIO1_FUNC_Pos)
+
+#define APP_SYS_CFG_GPIO2_FUNC_Pos (4U)
+#define APP_SYS_CFG_GPIO2_FUNC_Msk (3U << APP_SYS_CFG_GPIO2_FUNC_Pos)
+
+#define APP_SYS_CFG_GPIO3_FUNC_Pos (6U)
+#define APP_SYS_CFG_GPIO3_FUNC_Msk (3U << APP_SYS_CFG_GPIO3_FUNC_Pos)
+
 #define APP_SYS_CFG_RST_Pos (15U)
 #define APP_SYS_CFG_RST_Msk (1U << APP_SYS_CFG_RST_Pos)
 
 #define APP_SYS_AUX_LED_R_Pos (0U)
 #define APP_SYS_AUX_LED_R_Msk (1U << APP_SYS_AUX_LED_R_Pos)
+
 #define APP_SYS_AUX_LED_G_Pos (1U)
 #define APP_SYS_AUX_LED_G_Msk (1U << APP_SYS_AUX_LED_G_Pos)
+
 #define APP_SYS_AUX_LED_B_Pos (2U)
 #define APP_SYS_AUX_LED_B_Msk (1U << APP_SYS_AUX_LED_B_Pos)
 
@@ -122,7 +136,7 @@ static inline void app_sys_utils_write_reg_aux(uint16_t data) {
         app_led_off(APP_LED_GREEN);
     }
 
-    if (data & APP_LED_BLUE) {
+    if (data & APP_SYS_AUX_LED_B_Msk) {
         app_led_on(APP_LED_BLUE);
     } else {
         app_led_off(APP_LED_BLUE);
diff --git a/src/app_uart.c b/src/app_uart.c
new file mode 100644
index 0000000..7c6671d
--- /dev/null
+++ b/src/app_uart.c
@@ -0,0 +1,11 @@
+#include "app_uart.h"
+
+void app_uart_init(void) {
+}
+
+uint16_t app_uart_module_reg_read(uint8_t addr) {
+    return 0x0000;
+}
+
+void app_uart_module_reg_write(uint8_t addr, uint16_t data) {
+}
\ No newline at end of file
diff --git a/src/main.c b/src/main.c
index 500c7a0..f25568b 100644
--- a/src/main.c
+++ b/src/main.c
@@ -9,6 +9,7 @@
 #include "app_gpio.h"
 #include "app_i2c_if.h"
 #include "app_sys_utils.h"
+#include "app_uart.h"
 
 int main(void) {
     BOARD_InitBootPins();
@@ -18,6 +19,7 @@ int main(void) {
     app_gpio_init();
     app_adc_init();
     app_dac_init();
+    app_uart_init();
     app_i2c_if_init();
 
     for (;;) {