diff --git a/libraries/AP_HAL_ChibiOS/hwdef/common/watchdog.c b/libraries/AP_HAL_ChibiOS/hwdef/common/watchdog.c
index a5320c5aab..8a9b26e77a 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/common/watchdog.c
+++ b/libraries/AP_HAL_ChibiOS/hwdef/common/watchdog.c
@@ -63,7 +63,7 @@ void stm32_watchdog_init(void)
 {
     // setup for 2s reset
     IWDGD.KR = 0x5555;
-    IWDGD.PR = 16;
+    IWDGD.PR = 2; // div16
     IWDGD.RLR = 0xFFF;
     IWDGD.KR = 0xCCCC;
     watchdog_enabled = true;