diff --git a/main/CMakeLists.txt b/main/CMakeLists.txt
index 20a3a6b..111cffb 100644
--- a/main/CMakeLists.txt
+++ b/main/CMakeLists.txt
@@ -8,6 +8,7 @@ idf_component_register(SRCS
     "impl/impl_dht.c"
     "impl/impl_epd.c"
     "impl/impl_lvgl.c"
+    "impl/impl_sdfs.c"
     "interface/if_standby.c"
     "interface/if_wifi.c"
     "lib/epd-spi/src/epd_common.c"
@@ -165,6 +166,7 @@ idf_component_register(SRCS
     "lib/lvgl/src/widgets/lv_switch.c"
     "lib/lvgl/src/widgets/lv_table.c"
     "lib/lvgl/src/widgets/lv_textarea.c"
+    "service/service_battery.c"
     "service/service_clock.c"
     "service/service_dht.c"
     "service/service_wifi.c"
diff --git a/main/impl/impl_epd.c b/main/impl/impl_epd.c
index 1ee6a87..c66a271 100644
--- a/main/impl/impl_epd.c
+++ b/main/impl/impl_epd.c
@@ -8,7 +8,7 @@
 #define EPD_GPIO_RES          GPIO_NUM_10
 #define EPD_GPIO_DC           GPIO_NUM_12
 
-#define EPD_SPI_HOST          SPI2_HOST
+#define EPD_SPI_HOST          SPI3_HOST
 #define EPD_SPI_SPEED         (16 * 1000 * 1000) /* 16MHz */
 #define EPD_SPI_MAX_XFER_SIZE (1024)
 
diff --git a/main/impl/impl_sdfs.c b/main/impl/impl_sdfs.c
new file mode 100644
index 0000000..3dab56a
--- /dev/null
+++ b/main/impl/impl_sdfs.c
@@ -0,0 +1,18 @@
+#include "impl_sdfs.h"
+
+#include "lvgl.h"
+
+lv_fs_res_t impl_sdfs_open(lv_fs_drv_t *drv, void *file_p, const char *path, lv_fs_mode_t mode) {
+    //
+    return LV_FS_RES_OK;
+}
+
+lv_fs_res_t impl_sdfs_close(lv_fs_drv_t *drv, void *file_p) {
+    //
+    return LV_FS_RES_OK;
+}
+
+esp_err_t impl_sdfs_init(void) {
+    //
+    return ESP_OK;
+}
\ No newline at end of file
diff --git a/main/impl/impl_sdfs.h b/main/impl/impl_sdfs.h
new file mode 100644
index 0000000..9ff4b1f
--- /dev/null
+++ b/main/impl/impl_sdfs.h
@@ -0,0 +1,6 @@
+#ifndef IMPL_SDFS_H
+#define IMPL_SDFS_H
+
+#include "esp_system.h"
+
+#endif
\ No newline at end of file
diff --git a/main/lib/ltc2941/ltc2941.c b/main/lib/ltc2941/ltc2941.c
index e69de29..189d10d 100644
--- a/main/lib/ltc2941/ltc2941.c
+++ b/main/lib/ltc2941/ltc2941.c
@@ -0,0 +1,42 @@
+#include "ltc2941.h"
+
+#define LTC2941_REG_STATUS  0x00
+#define LTC2941_REG_CONTROL 0x01
+#define LTC2941_REG_CHARGE_MSB 0x02
+#define LTC2941_REG_CHARGE_LSB 0x03
+
+ltc2941_ret_t ltc2941_init(ltc2941_t *bat) {
+
+    uint8_t control_reg = 
+        ((bat->config.alert_mode & 0x03U) << 0x01U) |
+        ((bat->config.prescaler & 0x07U) << 0x03U) |
+        ((bat->config.alert_level & 0x03U) << 0x06U);
+
+    bat->cb.write_register_cb(bat->user_data, LTC2941_REG_CONTROL, control_reg);
+    return LTC2941_OK;
+}
+
+ltc2941_ret_t ltc2941_read_status(ltc2941_t *bat, uint8_t *status) {
+    return bat->cb.read_register_cb(bat->user_data, LTC2941_REG_STATUS, status);
+}
+
+ltc2941_ret_t ltc2941_read_charge(ltc2941_t *bat, uint16_t *charge) {
+    uint8_t reg = 0x00;
+    bat->cb.read_register_cb(bat->user_data, LTC2941_REG_CHARGE_MSB, &reg);
+    *charge = reg << 0x08U;
+
+    bat->cb.read_register_cb(bat->user_data, LTC2941_REG_CHARGE_LSB, &reg);
+    *charge |= reg;
+
+    return LTC2941_OK;
+}
+
+ltc2941_ret_t ltc2941_write_charge(ltc2941_t *bat, uint16_t charge) {
+    uint8_t reg = (charge >> 0x08U); // MSB
+    bat->cb.write_register_cb(bat->user_data, LTC2941_REG_CHARGE_MSB, reg);
+
+    reg = (charge & 0xFFU); // LSB
+    bat->cb.write_register_cb(bat->user_data, LTC2941_REG_CHARGE_LSB, reg);
+
+    return LTC2941_OK;
+}
\ No newline at end of file
diff --git a/main/lib/ltc2941/ltc2941.h b/main/lib/ltc2941/ltc2941.h
index e69de29..b32deed 100644
--- a/main/lib/ltc2941/ltc2941.h
+++ b/main/lib/ltc2941/ltc2941.h
@@ -0,0 +1,64 @@
+#ifndef __LTC2941_BATTERY_H
+#define __LTC2941_BATTERY_H
+
+#include <stdint.h>
+
+typedef enum {
+    LTC2941_OK,
+    LTC2941_ERROR
+} ltc2941_ret_t;
+
+typedef enum {
+    LTC2941_ALERT_3_0V = 0x03,
+    LTC2941_ALERT_2_9V = 0x02,
+    LTC2941_ALERT_2_8V = 0x01,
+    LTC2941_ALERT_OFF  = 0x00
+} ltc2941_battery_alert_t;
+
+typedef enum {
+    LTC2941_PRE_1   = 0x00,
+    LTC2941_PRE_2   = 0x01,
+    LTC2941_PRE_4   = 0x02,
+    LTC2941_PRE_8   = 0x03,
+    LTC2941_PRE_16  = 0x04,
+    LTC2941_PRE_32  = 0x05,
+    LTC2941_PRE_64  = 0x06,
+    LTC2941_PRE_128 = 0x07
+} ltc2941_prescale_t;
+
+typedef enum {
+    LTC2941_ALERT_DISABLED = 0x00,
+    LTC2941_ALERT_CC = 0x01,
+    LTC2941_ALERT_AL = 0x02
+} ltc2941_alert_mode_t;
+
+typedef struct {
+    ltc2941_ret_t (*write_register_cb)(void * handle, uint8_t reg, uint8_t value);
+    ltc2941_ret_t (*read_register_cb)(void *handle, uint8_t reg, uint8_t *value);
+} ltc2941_cb_t;
+
+typedef struct {
+    ltc2941_prescale_t prescaler;
+    ltc2941_alert_mode_t alert_mode;
+    ltc2941_battery_alert_t alert_level; 
+} ltc2941_config_t;
+
+typedef struct {
+    ltc2941_cb_t cb;
+    ltc2941_config_t config;
+    void *user_data;
+} ltc2941_t;
+
+#define LTC2941_STATUS_CHIPID    (1 << 7U)
+#define LTC2941_STATUS_OVERFLOW  (1 << 5U)
+#define LTC2941_STATUS_ALRT_HIGH (1 << 3U)
+#define LTC2941_STATUS_ALRT_LOW  (1 << 2U)
+#define LTC2941_STATUS_ALRT_VBAT (1 << 1U)
+#define LTC2941_STATUS_ALRT_UVLO 1U
+
+ltc2941_ret_t ltc2941_init(ltc2941_t *bat);
+ltc2941_ret_t ltc2941_read_status(ltc2941_t *bat, uint8_t *status);
+ltc2941_ret_t ltc2941_read_charge(ltc2941_t *bat, uint16_t *charge);
+ltc2941_ret_t ltc2941_write_charge(ltc2941_t *bat, uint16_t charge);
+
+#endif
\ No newline at end of file
diff --git a/main/service/service_battery.c b/main/service/service_battery.c
new file mode 100644
index 0000000..e69de29
diff --git a/main/service/service_battery.h b/main/service/service_battery.h
new file mode 100644
index 0000000..e69de29
diff --git a/main/service/service_clock.c b/main/service/service_clock.c
index 5ff2706..33b4a7c 100644
--- a/main/service/service_clock.c
+++ b/main/service/service_clock.c
@@ -10,7 +10,7 @@
 
 static TaskHandle_t s_clock_task_handle;
 
-static const char *s_wday_array[] = {"SUN", "MON", "TUE", "WED", "THU", "FRI"};
+static const char *s_wday_array[] = {"SUN", "MON", "TUE", "WED", "THU", "FRI", "SAT"};
 
 void clock_task(void *pvParameters) {
     struct tm timeinfo;
diff --git a/main/service/service_wifi.c b/main/service/service_wifi.c
index d6264f7..073346e 100644
--- a/main/service/service_wifi.c
+++ b/main/service/service_wifi.c
@@ -24,14 +24,36 @@ static QueueHandle_t s_service_wifi_event_queue;
 static uint8_t s_retry_count = 0;
 
 typedef enum {
-    SERVICE_WIFI_EVENT_CONNECTING,
-    SERVICE_WIFI_EVENT_DISCONNECTED,
-    SERVICE_WIFI_EVENT_CONNECTED,
-    SERVICE_WIFI_EVENT_START_DPP,
+    SERVICE_WIFI_EV_STATE_CHANGE,
 } service_wifi_event_t;
 
+typedef enum {
+    SERVICE_WIFI_STATE_DISABLED,
+    SERVICE_WIFI_STATE_DPP,
+    SERVICE_WIFI_STATE_CONNECTING,
+    SERVICE_WIFI_STATE_CONNECTED,
+    SERVICE_WIFI_STATE_IP_READY,
+} service_wifi_state_t;
+
+typedef struct {
+    service_wifi_event_t ev;
+    void                *payload;
+} service_wifi_request_t;
+
+static esp_err_t service_wifi_update_state(service_wifi_state_t new_state) {
+    service_wifi_request_t req = {
+        .ev      = SERVICE_WIFI_EV_STATE_CHANGE,
+        .payload = (void *)new_state,
+    };
+
+    if(xQueueSend(s_service_wifi_event_queue, &req, 0) != pdPASS) {
+        return ESP_FAIL;
+    }
+
+    return ESP_OK;
+}
+
 static void service_wifi_event_handler(void *arg, esp_event_base_t event_base, int32_t event_id, void *event_data) {
-    service_wifi_event_t service_ev;
     if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_START) {
         esp_wifi_connect();
     } else if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_DISCONNECTED) {
@@ -41,8 +63,7 @@ static void service_wifi_event_handler(void *arg, esp_event_base_t event_base, i
         }
     } else if (event_base == IP_EVENT && event_id == IP_EVENT_STA_GOT_IP) {
         s_retry_count = 0;
-        service_ev    = SERVICE_WIFI_EVENT_CONNECTED;
-        xQueueSend(s_service_wifi_event_queue, &service_ev, 0);
+        service_wifi_update_state(SERVICE_WIFI_STATE_IP_READY);
     }
 }
 
@@ -89,15 +110,18 @@ void service_wifi_task(void *pvParameters) {
     ESP_ERROR_CHECK(esp_wifi_set_config(WIFI_IF_STA, &wifi_config));
     ESP_ERROR_CHECK(esp_wifi_start());
 
-    service_wifi_event_t queue_event;
+    service_wifi_request_t request;
     for (;;) {
-        if (xQueueReceive(s_service_wifi_event_queue, &queue_event, portMAX_DELAY) == pdPASS) {
-            switch (queue_event) {
-                case SERVICE_WIFI_EVENT_CONNECTED:
-                    if_standby_component_update(IF_STANDBY_COMPONENT_WIFI, "\U000F0928");
-                    break;
-                default:
-                    break;
+        if (xQueueReceive(s_service_wifi_event_queue, &request, portMAX_DELAY) == pdPASS) {
+            if (request.ev == SERVICE_WIFI_EV_STATE_CHANGE) {
+                service_wifi_state_t state = (service_wifi_state_t)request.payload;
+                switch (state) {
+                    case SERVICE_WIFI_STATE_IP_READY:
+                        if_standby_component_update(IF_STANDBY_COMPONENT_WIFI, "\U000F0928");
+                        break;
+                    default:
+                        break;
+                }
             }
         }
     }
@@ -114,7 +138,7 @@ esp_err_t service_wifi_init(void) {
     ESP_ERROR_CHECK(esp_event_handler_register(WIFI_EVENT, ESP_EVENT_ANY_ID, service_wifi_event_handler, NULL));
     ESP_ERROR_CHECK(esp_event_handler_register(IP_EVENT, IP_EVENT_STA_GOT_IP, service_wifi_event_handler, NULL));
 
-    s_service_wifi_event_queue = xQueueCreate(2, sizeof(service_wifi_event_t));
+    s_service_wifi_event_queue = xQueueCreate(2, sizeof(service_wifi_request_t));
     if (s_service_wifi_event_queue == NULL) {
         return ESP_FAIL;
     }
@@ -126,3 +150,7 @@ esp_err_t service_wifi_init(void) {
 
     return ESP_OK;
 }
+
+esp_err_t service_wifi_notify() {
+    return ESP_OK;
+}
diff --git a/main/service/service_wifi.h b/main/service/service_wifi.h
index 4eaad6c..d4b3b1b 100644
--- a/main/service/service_wifi.h
+++ b/main/service/service_wifi.h
@@ -3,6 +3,13 @@
 
 #include "esp_system.h"
 
+typedef enum {
+    SERVICE_WIFI_NOTIFY_STANDBY_REFRESH,
+    SERVICE_WIFI_NOTIFY_SETTINGS_REFRESH,
+} service_wifi_notify_t;
+
 esp_err_t service_wifi_init(void);
+esp_err_t service_wifi_notify();
+
 
 #endif
\ No newline at end of file