diff --git a/src/main.c b/src/main.c
index 7d86220..eaf2a50 100644
--- a/src/main.c
+++ b/src/main.c
@@ -47,6 +47,8 @@ enum MODES {
 #define SCAN_BOOTLD_BTN     (1 << 3)
 #define BLE_NEXT_STEP       (1 << 4)
 
+#define CHARGE_STT_PIN      GPIO_Pin_0 // PA0
+
 static tmosTaskID common_taskid = INVALID_TASK_ID ;
 
 volatile uint16_t fb[LED_COLS] = {0};
@@ -104,6 +106,8 @@ void poweroff()
 	// Configure wake-up
 	GPIOA_ModeCfg(KEY1_PIN, GPIO_ModeIN_PD);
 	GPIOA_ITModeCfg(KEY1_PIN, GPIO_ITMode_RiseEdge);
+	GPIOA_ModeCfg(CHARGE_STT_PIN, GPIO_ModeIN_PU);
+	GPIOA_ITModeCfg(CHARGE_STT_PIN, GPIO_ITMode_FallEdge);
 	PFIC_EnableIRQ(GPIO_A_IRQn);
 	PWR_PeriphWakeUpCfg(ENABLE, RB_SLP_GPIO_WAKE, Long_Delay);
 
@@ -310,6 +314,93 @@ static void debug_init()
 	UART1_BaudRateCfg(921600);
 }
 
+uint16_t adcBuff[40];
+static int read_batt_raw()
+{
+	int ret = 0;
+	/* adc 1 - pa5 */
+	PRINT("\n2.Single channel sampling...\n");
+	GPIOA_ModeCfg(GPIO_Pin_5, GPIO_ModeIN_Floating);
+	ADC_ExtSingleChSampInit(SampleFreq_3_2, ADC_PGA_0);
+
+	int16_t RoughCalib_Value = ADC_DataCalib_Rough();
+	PRINT("RoughCalib_Value =%d \n", RoughCalib_Value);
+
+	ADC_ChannelCfg(1);
+
+	for(int i = 0; i < 20; i++) {
+		adcBuff[i] = ADC_ExcutSingleConver() + RoughCalib_Value;
+		ret += adcBuff[i];
+	}
+	for(int i = 0; i < 20; i++) {
+		PRINT("%d \n", adcBuff[i]);
+	}
+
+	return ret / 20;
+}
+
+static int is_charging()
+{
+	GPIOA_ModeCfg(CHARGE_STT_PIN, GPIO_ModeIN_PU);
+	return GPIOA_ReadPortPin(CHARGE_STT_PIN) == 0;
+}
+
+static void disp_bat_stt(int bat_percent, int col, int row)
+{
+	if (bat_percent < 0) {
+		xbm2fb(&batwarn_xbm, fb, col, row);
+		return;
+	}
+
+	xbm2fb(&bat_xbm, fb, col, row);
+	bat_percent /= 10;
+	for (int i=1; i <= bat_percent; i++) {
+		fb[col + i] = fb[col];
+	}
+}
+
+#define ZERO_PERCENT_THRES      (3.3)
+#define _100_PERCENT_THRES      (4.2)
+#define ADC_MAX_VAL             (4096.0) // 12 bit
+#define ADC_MAX_VOLT            (2.1)   // Volt
+#define R1                      (182.0) // kOhm
+#define R2                      (100.0) // kOhm
+#define PERCENT_RANGE           (_100_PERCENT_THRES - ZERO_PERCENT_THRES)
+#define VOLT_DIV(v)             ((v) / (R1 + R2) * R2) // Voltage divider
+#define VOLT_DIV_INV(v)         ((v) / R2 * (R1 + R2)) // .. Inverse
+#define ADC2VOLT(raw)           ((raw) / ADC_MAX_VAL * ADC_MAX_VOLT)
+#define VOLT2ADC(volt)          ((volt) / ADC_MAX_VOLT * ADC_MAX_VAL)
+
+static int bat_raw2percent(int r)
+{
+	float vadc = ADC2VOLT(r);
+	float vbat = VOLT_DIV_INV(vadc);
+	float strip = vbat - ZERO_PERCENT_THRES;
+	if (strip < PERCENT_RANGE) {
+		// Negative values meaning the battery is not connected or died
+		return (int)(strip / PERCENT_RANGE * 100.0);
+	}
+	return 100;
+}
+
+static void disp_charging()
+{
+	int blink = 0;
+	while (1) {
+		int percent = bat_raw2percent(read_batt_raw());
+
+		if (is_charging()) {
+			disp_bat_stt(blink ? percent : 0, 7, 2);
+			blink = !blink;
+			DelayMs(300);
+		} else {
+			disp_bat_stt(percent, 7, 2);
+			DelayMs(500);
+			return;
+		}
+	}
+}
+
 int main()
 {
 	SetSysClock(CLK_SOURCE_PLL_60MHz);
@@ -327,6 +418,8 @@ int main()
 	PFIC_EnableIRQ(TMR0_IRQn);
 
 	bmlist_init(LED_COLS * 4);
+
+	disp_charging();
 	
 	play_splash(&splash, 0, 0);
 
diff --git a/src/res/bat-icon.xbm b/src/res/bat-icon.xbm
new file mode 100644
index 0000000..c62e206
--- /dev/null
+++ b/src/res/bat-icon.xbm
@@ -0,0 +1,5 @@
+#define bat_icon_width 13
+#define bat_icon_height 7
+static unsigned char bat_icon_bits[] = {
+   0xff, 0x0f, 0x01, 0x08, 0x01, 0x18, 0x01, 0x18, 0x01, 0x18, 0x01, 0x08,
+   0xff, 0x0f };
diff --git a/src/res/bat-warn-icon.xbm b/src/res/bat-warn-icon.xbm
new file mode 100644
index 0000000..6c0276b
--- /dev/null
+++ b/src/res/bat-warn-icon.xbm
@@ -0,0 +1,5 @@
+#define bat_warn_icon_width 13
+#define bat_warn_icon_height 7
+static unsigned char bat_warn_icon_bits[] = {
+   0xff, 0x0f, 0x01, 0x08, 0x01, 0x18, 0xf5, 0x1b, 0x01, 0x18, 0x01, 0x08,
+   0xff, 0x0f };
diff --git a/src/resource.c b/src/resource.c
index ed4766b..a8f8d14 100644
--- a/src/resource.c
+++ b/src/resource.c
@@ -2,6 +2,8 @@
 
 #include "res/bluetooth.xbm"
 #include "res/foss-asia-2.xbm"
+#include "res/bat-icon.xbm"
+#include "res/bat-warn-icon.xbm"
 
 xbm_t bluetooth = {
 	.bits = bluetooth_bits, 
@@ -15,4 +17,18 @@ xbm_t splash = {
 	.w = foss_asia_2_width, 
 	.h = foss_asia_2_height,
 	.fh = 11
+};
+
+xbm_t bat_xbm = {
+	.bits = bat_icon_bits, 
+	.w = bat_icon_width, 
+	.h = bat_icon_height,
+	.fh = 11
+};
+
+xbm_t batwarn_xbm = {
+	.bits = bat_warn_icon_bits, 
+	.w = bat_warn_icon_width, 
+	.h = bat_warn_icon_height,
+	.fh = 11
 };
\ No newline at end of file
diff --git a/src/resource.h b/src/resource.h
index df91e37..968d725 100644
--- a/src/resource.h
+++ b/src/resource.h
@@ -6,5 +6,7 @@
 
 extern xbm_t bluetooth;
 extern xbm_t splash;
+extern xbm_t bat_xbm;
+extern xbm_t batwarn_xbm;
 
 #endif /* __RES_H__ */