From 71ef4ef231ae63c50e0a5b3bacde511e79b457e7 Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <andrew@tridgell.net>
Date: Wed, 12 Feb 2020 14:05:30 +1100
Subject: [PATCH] AP_SerialLED: added define for LED limit

---
 libraries/AP_SerialLED/AP_SerialLED.cpp | 2 +-
 libraries/AP_SerialLED/AP_SerialLED.h   | 4 ++++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/libraries/AP_SerialLED/AP_SerialLED.cpp b/libraries/AP_SerialLED/AP_SerialLED.cpp
index 50573bf34a..247c211169 100644
--- a/libraries/AP_SerialLED/AP_SerialLED.cpp
+++ b/libraries/AP_SerialLED/AP_SerialLED.cpp
@@ -30,7 +30,7 @@ AP_SerialLED::AP_SerialLED()
 // set number of LEDs per pin
 bool AP_SerialLED::set_num_LEDs(uint8_t chan, uint8_t num_leds)
 {
-    if (chan >= 1 && chan <= 16 && num_leds <= 64) {
+    if (chan >= 1 && chan <= 16 && num_leds <= AP_SERIALLED_MAX_LEDS) {
         return hal.rcout->set_neopixel_num_LEDs(chan-1, num_leds);
     }
     return false;
diff --git a/libraries/AP_SerialLED/AP_SerialLED.h b/libraries/AP_SerialLED/AP_SerialLED.h
index 4bf90d43b6..a7f8d229b2 100644
--- a/libraries/AP_SerialLED/AP_SerialLED.h
+++ b/libraries/AP_SerialLED/AP_SerialLED.h
@@ -19,6 +19,10 @@
 
 #include <AP_HAL/AP_HAL.h>
 
+// limit number of LEDs, mostly to keep DMA memory consumption within
+// reasonable bounds
+#define AP_SERIALLED_MAX_LEDS 64
+
 class AP_SerialLED {
 public:
     AP_SerialLED();