From 4790339a7624e46d2ff62ad9c1899d8f58f3b065 Mon Sep 17 00:00:00 2001
From: Harald Barth <haba@kth.se>
Date: Mon, 15 Nov 2021 18:09:34 +0100
Subject: [PATCH] only update if changed

---
 DCCWaveform.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/DCCWaveform.cpp b/DCCWaveform.cpp
index 99a59a3..e13fda4 100644
--- a/DCCWaveform.cpp
+++ b/DCCWaveform.cpp
@@ -36,6 +36,7 @@ volatile uint8_t DCCWaveform::numAckSamples=0;
 uint8_t DCCWaveform::trailingEdgeCounter=0;
 static unsigned long lastLCDCurrentDisplay=0;
 #define LCD_SAMPLE_PERIOD 2000 // milliseconds
+static uint16_t lastLCDCurrent=0xFFFF;
 
 void DCCWaveform::begin(MotorDriver * mainDriver, MotorDriver * progDriver) {
   mainTrack.motorDriver=mainDriver;
@@ -186,7 +187,11 @@ void DCCWaveform::checkPowerOverload(bool ackManagerActive) {
   }
   if (isMainTrack && now - lastLCDCurrentDisplay > LCD_SAMPLE_PERIOD) {
     lastLCDCurrentDisplay=now;
-    LCD(2,F("I= %dmA"), mainTrack.getCurrentmA());
+    uint16_t c=mainTrack.getCurrentmA();
+    if (c != lastLCDCurrent) {
+      lastLCDCurrent=c;
+      LCD(2,F("I=%dmA"), c);
+    }
   }
 }
 // For each state of the wave  nextState=stateTransform[currentState]