diff --git a/dev/adc.c b/device/adc.c
similarity index 99%
rename from dev/adc.c
rename to device/adc.c
index 369ad48..a9044d0 100644
--- a/dev/adc.c
+++ b/device/adc.c
@@ -6,7 +6,7 @@
  * @date 2023-11-06    MacRsh       First version
  */
 
-#include "adc.h"
+#include "include/device/adc.h"
 
 #ifdef MR_USING_ADC
 
diff --git a/dev/dac.c b/device/dac.c
similarity index 99%
rename from dev/dac.c
rename to device/dac.c
index 6d1368e..fb40197 100644
--- a/dev/dac.c
+++ b/device/dac.c
@@ -6,7 +6,7 @@
  * @date 2023-11-08    MacRsh       First version
  */
 
-#include "dac.h"
+#include "include/device/dac.h"
 
 #ifdef MR_USING_DAC
 
diff --git a/dev/gpio.c b/device/gpio.c
similarity index 98%
rename from dev/gpio.c
rename to device/gpio.c
index 59587ec..1715bf5 100644
--- a/dev/gpio.c
+++ b/device/gpio.c
@@ -6,7 +6,7 @@
  * @date 2023-11-08    MacRsh       First version
  */
 
-#include "gpio.h"
+#include "include/device/gpio.h"
 
 #ifdef MR_USING_GPIO
 
diff --git a/dev/i2c.c b/device/i2c.c
similarity index 99%
rename from dev/i2c.c
rename to device/i2c.c
index b67b24d..7d2e3d9 100644
--- a/dev/i2c.c
+++ b/device/i2c.c
@@ -6,7 +6,7 @@
  * @date 2023-11-09    MacRsh       First version
  */
 
-#include "i2c.h"
+#include "include/device/i2c.h"
 
 #ifdef MR_USING_I2C
 
diff --git a/dev/spi.c b/device/spi.c
similarity index 99%
rename from dev/spi.c
rename to device/spi.c
index ec5a23e..f18a97d 100644
--- a/dev/spi.c
+++ b/device/spi.c
@@ -6,12 +6,12 @@
  * @date 2023-11-01    MacRsh       First version
  */
 
-#include "spi.h"
+#include "include/device/spi.h"
 
 #ifdef MR_USING_SPI
 
 #ifdef MR_USING_GPIO
-#include "gpio.h"
+#include "include/device/gpio.h"
 #else
 #warning "Please define MR_USING_GPIO. Otherwise SPI-CS will not work."
 #endif /* MR_USING_GPIO */
diff --git a/dev/timer.c b/device/timer.c
similarity index 98%
rename from dev/timer.c
rename to device/timer.c
index 033d222..69ba624 100644
--- a/dev/timer.c
+++ b/device/timer.c
@@ -6,7 +6,7 @@
  * @date 2023-11-15    MacRsh       First version
  */
 
-#include "timer.h"
+#include "include/device/timer.h"
 
 #ifdef MR_USING_TIMER
 
@@ -53,6 +53,9 @@ static ssize_t mr_timer_write(struct mr_dev *dev, int off, const void *buf, size
         timer->reload = (uint32_t)(((float)timeout / 1000000.0f) * (float)timer->config.freq + 0.5f);
 
         ops->start(timer, timer->prescaler, timer->reload);
+    } else
+    {
+
     }
 
     return wr_size;
diff --git a/dev/uart.c b/device/uart.c
similarity index 99%
rename from dev/uart.c
rename to device/uart.c
index 952ede8..ac05229 100644
--- a/dev/uart.c
+++ b/device/uart.c
@@ -6,7 +6,7 @@
  * @date 2023-10-20    MacRsh       First version
  */
 
-#include "uart.h"
+#include "include/device/uart.h"
 
 #ifdef MR_USING_UART
 
diff --git a/docs/coding_style.md b/document/coding_style.md
similarity index 100%
rename from docs/coding_style.md
rename to document/coding_style.md
diff --git a/drv/mr_drv.h b/driver/mr_drv.h
similarity index 100%
rename from drv/mr_drv.h
rename to driver/mr_drv.h
diff --git a/dev/adc.h b/include/device/adc.h
similarity index 100%
rename from dev/adc.h
rename to include/device/adc.h
diff --git a/dev/dac.h b/include/device/dac.h
similarity index 100%
rename from dev/dac.h
rename to include/device/dac.h
diff --git a/dev/gpio.h b/include/device/gpio.h
similarity index 100%
rename from dev/gpio.h
rename to include/device/gpio.h
diff --git a/dev/i2c.h b/include/device/i2c.h
similarity index 96%
rename from dev/i2c.h
rename to include/device/i2c.h
index 9189607..269ae43 100644
--- a/dev/i2c.h
+++ b/include/device/i2c.h
@@ -41,7 +41,7 @@ extern "C" {
 }
 
 /**
- * @struct I2C configuration structure.
+ * @brief I2C configuration structure.
  */
 struct mr_i2c_config
 {
@@ -68,7 +68,7 @@ struct mr_i2c_bus
 };
 
 /**
- * @struct I2C bus operations structure.
+ * @brief I2C bus operations structure.
  */
 struct mr_i2c_bus_ops
 {
@@ -87,7 +87,7 @@ struct mr_i2c_bus_ops
 #define MR_I2C_ADDR_BITS_10             (10)                        /**< 10 bit address */
 
 /**
- * @struct I2C device structure.
+ * @brief I2C device structure.
  */
 struct mr_i2c_dev
 {
diff --git a/dev/spi.h b/include/device/spi.h
similarity index 99%
rename from dev/spi.h
rename to include/device/spi.h
index 63da912..b6a6a29 100644
--- a/dev/spi.h
+++ b/include/device/spi.h
@@ -127,7 +127,7 @@ struct mr_spi_bus_ops
 #define MR_SPI_CS_ACTIVE_NONE           (2)                         /**< No active */
 
 /**
- * @struct SPI device structure.
+ * @brief SPI device structure.
  */
 struct mr_spi_dev
 {
diff --git a/dev/timer.h b/include/device/timer.h
similarity index 98%
rename from dev/timer.h
rename to include/device/timer.h
index 4352b83..74c6da5 100644
--- a/dev/timer.h
+++ b/include/device/timer.h
@@ -89,6 +89,7 @@ struct mr_timer_ops
     int (*channel_configure)(struct mr_timer *timer, int channel, int mode);
     void (*start)(struct mr_timer *timer, uint32_t prescaler, uint32_t period);
     void (*stop)(struct mr_timer *timer);
+    void (*write_duty)(struct mr_timer *timer);
 };
 
 /**
diff --git a/dev/uart.h b/include/device/uart.h
similarity index 97%
rename from dev/uart.h
rename to include/device/uart.h
index bdcdc96..70859f3 100644
--- a/dev/uart.h
+++ b/include/device/uart.h
@@ -67,7 +67,7 @@ extern "C" {
 }
 
 /**
- * @struct UART configuration structure.
+ * @brief UART configuration structure.
  */
 struct mr_uart_config
 {
@@ -81,7 +81,7 @@ struct mr_uart_config
 };
 
 /**
- * @struct UART structure.
+ * @brief UART structure.
  */
 struct mr_uart
 {
@@ -95,7 +95,7 @@ struct mr_uart
 };
 
 /**
- * @struct UART operations structure.
+ * @brief UART operations structure.
  */
 struct mr_uart_ops
 {
diff --git a/inc/mr_api.h b/include/mr_api.h
similarity index 100%
rename from inc/mr_api.h
rename to include/mr_api.h
diff --git a/inc/mr_def.h b/include/mr_def.h
similarity index 98%
rename from inc/mr_def.h
rename to include/mr_def.h
index 2ae1ad8..38dbd4e 100644
--- a/inc/mr_def.h
+++ b/include/mr_def.h
@@ -192,8 +192,8 @@ struct mr_dev;
 /**
  * @brief Descriptor control command.
  */
-#define MR_CTRL_SET_OFFSET              ((0x01|0x80) << 28)         /**< Set offset */
-#define MR_CTRL_GET_OFFSET              ((0x02|0x00) << 28)         /**< Get offset */
+#define MR_CTRL_SET_OFFSET              ((0x01|0x80) << 24)         /**< Set offset */
+#define MR_CTRL_GET_OFFSET              ((0x02|0x00) << 24)         /**< Get offset */
 
 /**
  * @brief Device control general command.
diff --git a/inc/mr_lib.h b/include/mr_lib.h
similarity index 100%
rename from inc/mr_lib.h
rename to include/mr_lib.h
diff --git a/inc/mr_service.h b/include/mr_service.h
similarity index 100%
rename from inc/mr_service.h
rename to include/mr_service.h
diff --git a/src/dev.c b/source/device.c
similarity index 100%
rename from src/dev.c
rename to source/device.c
diff --git a/src/service.c b/source/service.c
similarity index 99%
rename from src/service.c
rename to source/service.c
index f8377d9..940e347 100644
--- a/src/service.c
+++ b/source/service.c
@@ -151,7 +151,7 @@ MR_WEAK int mr_printf_output(const char *buf, size_t size)
  */
 int mr_printf(const char *fmt, ...)
 {
-    char buf[256] = {0};
+    char buf[128] = {0};
     va_list args = MR_NULL;
 
     va_start(args, fmt);