From 441812abcc1c38f361be0ab05f866bc0fbdb157e Mon Sep 17 00:00:00 2001
From: matt venn <matt@mattvenn.net>
Date: Mon, 9 Jul 2018 14:06:52 +0200
Subject: [PATCH 1/2] fixed LED sync overflow bug

---
 src/Kaleidoscope-LEDControl.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Kaleidoscope-LEDControl.cpp b/src/Kaleidoscope-LEDControl.cpp
index 4ae30a6d..a5f41d90 100644
--- a/src/Kaleidoscope-LEDControl.cpp
+++ b/src/Kaleidoscope-LEDControl.cpp
@@ -151,8 +151,8 @@ kaleidoscope::EventHandlerResult LEDControl::beforeReportingState(void) {
   if (paused)
     return kaleidoscope::EventHandlerResult::OK;
 
-  uint16_t current_time = millis();
-  if ((current_time - syncTimer) > syncDelay) {
+  uint16_t elapsed = Kaleidoscope.millisAtCycleStart() - syncTimer;
+  if (elapsed > syncDelay) {
     syncLeds();
     syncTimer += syncDelay;
   }

From 76e8478ff6919eb1e463fa83cb36621ac5c86746 Mon Sep 17 00:00:00 2001
From: matt venn <matt@mattvenn.net>
Date: Tue, 10 Jul 2018 09:47:38 +0200
Subject: [PATCH 2/2] code comments

---
 src/Kaleidoscope-LEDControl.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/Kaleidoscope-LEDControl.cpp b/src/Kaleidoscope-LEDControl.cpp
index a5f41d90..80266a77 100644
--- a/src/Kaleidoscope-LEDControl.cpp
+++ b/src/Kaleidoscope-LEDControl.cpp
@@ -151,7 +151,11 @@ kaleidoscope::EventHandlerResult LEDControl::beforeReportingState(void) {
   if (paused)
     return kaleidoscope::EventHandlerResult::OK;
 
+  // unsigned subtraction means that as syncTimer rolls over
+  // the same interval is kept
   uint16_t elapsed = Kaleidoscope.millisAtCycleStart() - syncTimer;
+  // on some platforms, the subtraction in the comparison results in a signed
+  // operation, resulting in syncLeds() no longer getting called.
   if (elapsed > syncDelay) {
     syncLeds();
     syncTimer += syncDelay;