diff --git a/global.h b/global.h
index fea9fc3..f911331 100644
--- a/global.h
+++ b/global.h
@@ -404,6 +404,8 @@ int32_t adds32_safe(int32_t a, int32_t b);
 #define tim10_isr tim1_up_tim10_isr
 /** interrupt service routine for timer 11 */
 #define tim11_isr tim1_trg_com_tim11_isr
+/** get TIM_OC based on CHx identifier */
+#define TIM_OC(x) CAT2(TIM_OC,x)
 /** get TIM_IC based on CHx identifier */
 #define TIM_IC(x) CAT2(TIM_IC,x)
 /** get TIM_IC_IN_TI based on CHx identifier */