diff --git a/libraries/AP_HAL_ChibiOS/hwdef/common/chconf.h b/libraries/AP_HAL_ChibiOS/hwdef/common/chconf.h
index bcb19690d8..348817bd46 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/common/chconf.h
+++ b/libraries/AP_HAL_ChibiOS/hwdef/common/chconf.h
@@ -43,7 +43,9 @@
  * @brief   System time counter resolution.
  * @note    Allowed values are 16 or 32 bits.
  */
+#ifndef CH_CFG_ST_RESOLUTION
 #define CH_CFG_ST_RESOLUTION                32
+#endif
 
 /**
  * @brief   System tick frequency.