diff --git a/libraries/AP_SerialLED/AP_SerialLED.cpp b/libraries/AP_SerialLED/AP_SerialLED.cpp
index 4c78fe5328..9056255928 100644
--- a/libraries/AP_SerialLED/AP_SerialLED.cpp
+++ b/libraries/AP_SerialLED/AP_SerialLED.cpp
@@ -38,7 +38,7 @@ bool AP_SerialLED::set_num_profiled(uint8_t chan, uint8_t num_leds)
 {
     if (chan >= 1 && chan <= 16 && num_leds <= AP_SERIALLED_MAX_LEDS - 2) {
         // must have a clock
-        uint16_t Clock_mask = 0;
+        uint32_t Clock_mask = 0;
         if (!SRV_Channels::function_assigned((SRV_Channel::Aux_servo_function_t)((uint8_t)SRV_Channel::k_ProfiLED_Clock))) {
             return false;
         }