Add create_speed_lookup

diff --git a/Marlin/create_speed_lookuptable.py b/Marlin/create_speed_lookuptable.py
new file mode 100755 (executable)
index 0000000..0272bdc
--- /dev/null
+++ b/Marlin/create_speed_lookuptable.py
@@ -0,0 +1,53 @@
+#!/usr/bin/env python
+
+""" Generate the stepper delay lookup table for Marlin firmware. """
+
+import argparse
+
+__author__ = "Ben Gamari <bgamari@gmail.com>"
+__copyright__ = "Copyright 2012, Ben Gamari"
+__license__ = "GPL"
+
+parser = argparse.ArgumentParser(description=__doc__)
+parser.add_argument('-f', '--cpu-freq', type=int, default=16, help='CPU clockrate in MHz (default=16)')
+parser.add_argument('-d', '--divider', type=int, default=8, help='Timer/counter pre-scale divider (default=8)')
+args = parser.parse_args()
+
+cpu_freq = args.cpu_freq * 1000000
+timer_freq = cpu_freq / args.divider
+
+print "#ifndef SPEED_LOOKUPTABLE_H"
+print "#define SPEED_LOOKUPTABLE_H"
+print
+print '#include "Marlin.h"'
+print
+
+# Based on timer calculations of 'RepRap cartesian firmware' by Zack
+# Smith and Philip Tiefenbacher.
+
+print "const uint16_t speed_lookuptable_fast[256][2] PROGMEM = {"
+a = [ timer_freq / ((i*256)+32) for i in range(256) ]
+b = [ a[i] - a[i+1] for i in range(255) ]
+b.append(b[-1])
+for i in range(32):
+    print "  ",
+    for j in range(8):
+        print "{%d, %d}," % (a[8*i+j], b[8*i+j]),
+    print 
+print "};"
+print
+
+print "const uint16_t speed_lookuptable_slow[256][2] PROGMEM = {"
+a = [ timer_freq / ((i*8)+32) for i in range(256) ]
+b = [ a[i] - a[i+1] for i in range(255) ]
+b.append(b[-1])
+for i in range(32):
+    print "  ",
+    for j in range(8):
+        print "{%d, %d}," % (a[8*i+j], b[8*i+j]),
+    print 
+print "};"
+print
+
+print "#endif"
+