From af78d0cbfae1dbf2c5d37a363603d3411a8c02e0 Mon Sep 17 00:00:00 2001
From: daid <daid303@gmail.com>
Date: Fri, 15 Mar 2013 01:03:53 -0700
Subject: [PATCH] Merge pull request #1 from illuminarti/Fix_E_Speed
Fix step rate bug (especially for retraction)
---
Marlin/stepper.cpp | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/Marlin/stepper.cpp b/Marlin/stepper.cpp
index 4ed8bef40e..3bc5e9c892 100644
--- a/Marlin/stepper.cpp
+++ b/Marlin/stepper.cpp
@@ -62,6 +62,7 @@ static long acceleration_time, deceleration_time;
static unsigned short acc_step_rate; // needed for deccelaration start point
static char step_loops;
static unsigned short OCR1A_nominal;
+static unsigned short step_loops_nominal;
volatile long endstops_trigsteps[3]={0,0,0};
volatile long endstops_stepsTotal,endstops_stepsDone;
@@ -288,6 +289,8 @@ FORCE_INLINE void trapezoid_generator_reset() {
deceleration_time = 0;
// step_rate to timer interval
OCR1A_nominal = calc_timer(current_block->nominal_rate);
+ // make a note of the number of step loops required at nominal speed
+ step_loops_nominal = step_loops;
acc_step_rate = current_block->initial_rate;
acceleration_time = calc_timer(acc_step_rate);
OCR1A = acceleration_time;
@@ -665,6 +668,8 @@ ISR(TIMER1_COMPA_vect)
}
else {
OCR1A = OCR1A_nominal;
+ // ensure we're running at the correct step rate, even if we just came off an acceleration
+ step_loops = step_loops_nominal;
}
// If current block is finished, reset pointer