diff --git a/src/W800_SDK_v1.00.10/include/driver/wm_pmu.h b/src/W800_SDK_v1.00.10/include/driver/wm_pmu.h
index 9ea6955..8f14a69 100644
--- a/src/W800_SDK_v1.00.10/include/driver/wm_pmu.h
+++ b/src/W800_SDK_v1.00.10/include/driver/wm_pmu.h
@@ -146,6 +146,16 @@ void tls_pmu_sdio_isr_register(tls_pmu_irq_callback callback, void *arg);
  */
 void tls_pmu_clk_select(u8 bypass);
 
+/**
+ * @brief           Starts the internal 32K oscillator calibration cycle.
+ * 
+ * @param           None
+ * 
+ * @return          None
+ * 
+ */
+void tls_pmu_clk_calibrate(void);
+
 
 /**
  * @brief          	This function is used to start pmu timer0