diff --git a/libraries/AP_HAL_AVR/RCOutput_APM1.cpp b/libraries/AP_HAL_AVR/RCOutput_APM1.cpp
index ceaa3fe1e4..9d5da0ccc7 100644
--- a/libraries/AP_HAL_AVR/RCOutput_APM1.cpp
+++ b/libraries/AP_HAL_AVR/RCOutput_APM1.cpp
@@ -148,8 +148,8 @@ void APM1RCOutput::disable_ch(uint8_t ch) {
 
 /* constrain pwm to be between min and max pulsewidth. */
 static inline uint16_t constrain_period(uint16_t p) {
-    if (p > RC_INPUT_MAX_PULSEWIDTH) return RC_INPUT_MAX_PULSEWIDTH;
-    if (p < RC_INPUT_MIN_PULSEWIDTH) return RC_INPUT_MIN_PULSEWIDTH;
+    if (p > RC_OUTPUT_MAX_PULSEWIDTH) return RC_OUTPUT_MAX_PULSEWIDTH;
+    if (p < RC_OUTPUT_MIN_PULSEWIDTH) return RC_OUTPUT_MIN_PULSEWIDTH;
     return p;
 }
 
diff --git a/libraries/AP_HAL_AVR/RCOutput_APM2.cpp b/libraries/AP_HAL_AVR/RCOutput_APM2.cpp
index fdf5106f25..9993f91308 100644
--- a/libraries/AP_HAL_AVR/RCOutput_APM2.cpp
+++ b/libraries/AP_HAL_AVR/RCOutput_APM2.cpp
@@ -140,8 +140,8 @@ void APM2RCOutput::disable_ch(uint8_t ch) {
 
 /* constrain pwm to be between min and max pulsewidth. */
 static inline uint16_t constrain_period(uint16_t p) {
-    if (p > RC_INPUT_MAX_PULSEWIDTH) return RC_INPUT_MAX_PULSEWIDTH;
-    if (p < RC_INPUT_MIN_PULSEWIDTH) return RC_INPUT_MIN_PULSEWIDTH;
+    if (p > RC_OUTPUT_MAX_PULSEWIDTH) return RC_OUTPUT_MAX_PULSEWIDTH;
+    if (p < RC_OUTPUT_MIN_PULSEWIDTH) return RC_OUTPUT_MIN_PULSEWIDTH;
     return p;
 }