From 50059690e0192be879bcd7c48c45b790d41a53a4 Mon Sep 17 00:00:00 2001
From: Sebastianv650 <sebastian_v650@kabelmail.de>
Date: Sun, 20 Nov 2016 13:09:12 +0100
Subject: [PATCH 1/2] Allow UART ISRs inside the stepper ISR

If the stepper ISR takes too long, chars are lost which leads to serial
communication errors like "Line number not +1" or "Wrong checksum". In
worst case, the printer can even do crazy moves.

With this changes, UART interrupts are handled inside the stepper ISR.
This way, no chars should be lost.
---
 Marlin/stepper.cpp | 33 +++++++++++++++++++++++++++++----
 1 file changed, 29 insertions(+), 4 deletions(-)

diff --git a/Marlin/stepper.cpp b/Marlin/stepper.cpp
index 974dbad0e..95208d6f8 100644
--- a/Marlin/stepper.cpp
+++ b/Marlin/stepper.cpp
@@ -331,6 +331,14 @@ void Stepper::set_directions() {
 ISR(TIMER1_COMPA_vect) { Stepper::isr(); }
 
 void Stepper::isr() {
+  //Disable Timer0 ISRs and enable global ISR again to capture UART events (incoming chars)
+  #if ENABLED(ADVANCE) || ENABLED(LIN_ADVANCE)
+    CBI(TIMSK0, OCIE0A); //estepper ISR
+  #endif
+  CBI(TIMSK0, OCIE0B); //Temperature ISR
+  DISABLE_STEPPER_DRIVER_INTERRUPT();
+  sei();
+  
   if (cleaning_buffer_counter) {
     current_block = NULL;
     planner.discard_current_block();
@@ -339,6 +347,12 @@ void Stepper::isr() {
     #endif
     cleaning_buffer_counter--;
     OCR1A = 200; // Run at max speed - 10 KHz
+    //re-enable ISRs
+    #if ENABLED(ADVANCE) || ENABLED(LIN_ADVANCE)
+      SBI(TIMSK0, OCIE0A);
+    #endif
+    SBI(TIMSK0, OCIE0B);
+    ENABLE_STEPPER_DRIVER_INTERRUPT();
     return;
   }
 
@@ -368,6 +382,11 @@ void Stepper::isr() {
         if (current_block->steps[Z_AXIS] > 0) {
           enable_z();
           OCR1A = 2000; // Run at slow speed - 1 KHz
+          #if ENABLED(ADVANCE) || ENABLED(LIN_ADVANCE)
+            SBI(TIMSK0, OCIE0A);
+          #endif
+          SBI(TIMSK0, OCIE0B);
+          ENABLE_STEPPER_DRIVER_INTERRUPT();
           return;
         }
       #endif
@@ -378,6 +397,11 @@ void Stepper::isr() {
     }
     else {
       OCR1A = 2000; // Run at slow speed - 1 KHz
+      #if ENABLED(ADVANCE) || ENABLED(LIN_ADVANCE)
+        SBI(TIMSK0, OCIE0A);
+      #endif
+      SBI(TIMSK0, OCIE0B);
+      ENABLE_STEPPER_DRIVER_INTERRUPT();
       return;
     }
   }
@@ -402,10 +426,6 @@ void Stepper::isr() {
   // Take multiple steps per interrupt (For high speed moves)
   bool all_steps_done = false;
   for (int8_t i = 0; i < step_loops; i++) {
-    #ifndef USBCON
-      customizedSerial.checkRx(); // Check for serial chars.
-    #endif
-
     #if ENABLED(LIN_ADVANCE)
 
       counter_E += current_block->steps[E_AXIS];
@@ -694,6 +714,11 @@ void Stepper::isr() {
     current_block = NULL;
     planner.discard_current_block();
   }
+  #if ENABLED(ADVANCE) || ENABLED(LIN_ADVANCE)
+    SBI(TIMSK0, OCIE0A);
+  #endif
+  SBI(TIMSK0, OCIE0B);
+  ENABLE_STEPPER_DRIVER_INTERRUPT();
 }
 
 #if ENABLED(ADVANCE) || ENABLED(LIN_ADVANCE)

From 912704a0d85fdcdbe4f9783a9e007f6e83c11dab Mon Sep 17 00:00:00 2001
From: Sebastianv650 <sebastian_v650@kabelmail.de>
Date: Sun, 20 Nov 2016 18:17:42 +0100
Subject: [PATCH 2/2] Enable ISRs inside temperature ISR

to capture chars at UART at 250000 baud.
---
 Marlin/temperature.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Marlin/temperature.cpp b/Marlin/temperature.cpp
index f01c0862b..4895d1da9 100644
--- a/Marlin/temperature.cpp
+++ b/Marlin/temperature.cpp
@@ -1489,6 +1489,9 @@ void Temperature::set_current_temp_raw() {
 ISR(TIMER0_COMPB_vect) { Temperature::isr(); }
 
 void Temperature::isr() {
+  //Allow UART and stepper ISRs
+  CBI(TIMSK0, OCIE0B); //Disable Temperature ISR
+  sei();
 
   static uint8_t temp_count = 0;
   static TempState temp_state = StartupDelay;
@@ -1940,4 +1943,6 @@ void Temperature::isr() {
       if (!endstop_monitor_count) endstop_monitor();  // report changes in endstop status
     }
   #endif
+  
+  SBI(TIMSK0, OCIE0B); //re-enable Temperature ISR
 }