diff --git a/nrf5/hal/hal_pwm.h b/nrf5/hal/hal_pwm.h
index f60fb707d8..739a0b6829 100644
--- a/nrf5/hal/hal_pwm.h
+++ b/nrf5/hal/hal_pwm.h
@@ -31,11 +31,9 @@
 
 #include "nrf.h"
 
-#if NRF51
+// TODO: nrf51 series need Soft PWM. Not part of HAL.
 
-// TODO: create software PWM.
-
-#elif NRF52
+#if NRF52
 
 #define PWM0  ((NRF_PWM_Type *)NRF_PWM0_BASE)
 #define PWM0_IRQ_NUM PWM1_IRQn
@@ -58,4 +56,17 @@ typedef struct {
     uint8_t pwm_pin;
 } hal_pwm_init_t;
 
+/**
+  * @brief  PWM handle Structure definition
+  */
+typedef struct __PWM_HandleTypeDef
+{
+    NRF_PWM_Type               *instance;    /* PWM registers base address */
+    hal_pwm_init_t             init;         /* PWM initialization parameters */
+} PWM_HandleTypeDef;
+
+
+void hal_pwm_init(NRF_PWM_Type * p_instance, hal_pwm_init_t const * p_pwm_init);
+
+
 #endif // HAL_PWM_H__