--- /dev/null
+#!/usr/bin/python
+# Copyright 2007 by Bdale Garbee <bdale@gag.com>. GPLv2
+#
+# Program to emit PCB footprint for 16-lead QFN, 6x6mm
+# used by Freescale acceleromters like the MMA6556
+#
+
+# dimensions in mm from AN3111.pdf from Freescale, the Wettable Flank variant
+PinWidth = 0.50
+PinHeight = 0.85
+PinSpacing = 1.00
+Overall = 6.0
+CoreSquare = 4.00
+CornerSquare = 0.55
+MaskAdd = 0.15
+
+import sys
+
+# we're going to use the 1/100 of a mil fundamental unit form
+def mm2mils100( mm ):
+ return int( mm / 25.4 * 1000.0 * 100.0 + 0.5 )
+
+print '# author: Bdale Garbee'
+print '# email: bdale@gag.com'
+print '# dist-license: GPL 2'
+print '# use-license: unlimited'
+
+print 'Element[0x0 "AN3111" "" "" 0 0 0 0 0 100 0x0]'
+print "("
+# pad under the chip, no overall paste so we can control subset that gets paste
+print ' Pad[',\
+ mm2mils100(0), \
+ mm2mils100(0), \
+ mm2mils100(0), \
+ mm2mils100(0), \
+ mm2mils100(CoreSquare), \
+ mm2mils100(0), \
+ mm2mils100(CoreSquare + MaskAdd), \
+ '"G" "G" "square,nopaste"]'
+
+# copper sub-squares in a grid to set paste area
+for viarow in range (-1, 2):
+ for viacol in range (-1, 2):
+ print ' Pad[',\
+ mm2mils100(viacol * 1.4), \
+ mm2mils100(viarow * 1.4), \
+ mm2mils100(viacol * 1.4), \
+ mm2mils100(viarow * 1.4), \
+ mm2mils100(1.0), \
+ 0, \
+ mm2mils100(1.0), \
+ '"G" "G" "square"]'
+
+
+# corner mounting squares .. not connected to anything
+print ' Pad[',\
+ mm2mils100(CoreSquare/2 + 0.37 + CornerSquare/2), \
+ mm2mils100(CoreSquare/2 + 0.37 + CornerSquare/2), \
+ mm2mils100(CoreSquare/2 + 0.37 + CornerSquare/2), \
+ mm2mils100(CoreSquare/2 + 0.37 + CornerSquare/2), \
+ mm2mils100(CornerSquare), \
+ mm2mils100(0), \
+ mm2mils100(CornerSquare + MaskAdd), \
+ '"NC" "NC" 0x0100]'
+
+print ' Pad[',\
+ mm2mils100(CoreSquare/2 + 0.37 + CornerSquare/2), \
+ mm2mils100(-(CoreSquare/2 + 0.37 + CornerSquare/2)), \
+ mm2mils100(CoreSquare/2 + 0.37 + CornerSquare/2), \
+ mm2mils100(-(CoreSquare/2 + 0.37 + CornerSquare/2)), \
+ mm2mils100(CornerSquare), \
+ mm2mils100(0), \
+ mm2mils100(CornerSquare + MaskAdd), \
+ '"NC" "NC" 0x0100]'
+
+print ' Pad[',\
+ mm2mils100(-(CoreSquare/2 + 0.37 + CornerSquare/2)), \
+ mm2mils100(CoreSquare/2 + 0.37 + CornerSquare/2), \
+ mm2mils100(-(CoreSquare/2 + 0.37 + CornerSquare/2)), \
+ mm2mils100(CoreSquare/2 + 0.37 + CornerSquare/2), \
+ mm2mils100(CornerSquare), \
+ mm2mils100(0), \
+ mm2mils100(CornerSquare + MaskAdd), \
+ '"NC" "NC" 0x0100]'
+
+print ' Pad[',\
+ mm2mils100(-(CoreSquare/2 + 0.37 + CornerSquare/2)), \
+ mm2mils100(-(CoreSquare/2 + 0.37 + CornerSquare/2)), \
+ mm2mils100(-(CoreSquare/2 + 0.37 + CornerSquare/2)), \
+ mm2mils100(-(CoreSquare/2 + 0.37 + CornerSquare/2)), \
+ mm2mils100(CornerSquare), \
+ mm2mils100(0), \
+ mm2mils100(CornerSquare + MaskAdd), \
+ '"NC" "NC" 0x0100]'
+
+for pin in range (1,5):
+ print ' Pad[',\
+ mm2mils100(-2.5 + pin * PinSpacing), \
+ mm2mils100(-Overall/2 - 0.30 + PinWidth/2), \
+ mm2mils100(-2.5 + pin * PinSpacing), \
+ mm2mils100(-Overall/2 + 0.55 - PinWidth/2), \
+ mm2mils100(PinWidth), \
+ mm2mils100(0), \
+ mm2mils100(PinWidth + MaskAdd), \
+ '"pin%i"' % (13-pin), '"%i"' % (13-pin), '0x0100]'
+
+ print ' Pad[',\
+ mm2mils100(-2.5 + pin * PinSpacing), \
+ mm2mils100(+Overall/2 - 0.55 + PinWidth/2), \
+ mm2mils100(-2.5 + pin * PinSpacing), \
+ mm2mils100(+Overall/2 + 0.30 - PinWidth/2), \
+ mm2mils100(PinWidth), \
+ mm2mils100(0), \
+ mm2mils100(PinWidth + MaskAdd), \
+ '"pin%i"' % pin, '"%i"' % pin, '0x0100]'
+
+ print ' Pad[',\
+ mm2mils100(Overall/2 - 0.55 + PinWidth/2), \
+ mm2mils100(-2.5 + pin * PinSpacing), \
+ mm2mils100(Overall/2 + 0.30 - PinWidth/2), \
+ mm2mils100(-2.5 + pin * PinSpacing), \
+ mm2mils100(PinWidth), \
+ mm2mils100(0), \
+ mm2mils100(PinWidth + MaskAdd), \
+ '"pin%i"' % (9-pin), '"%i"' % (9-pin), '0x0100]'
+
+ print ' Pad[',\
+ mm2mils100(-Overall/2 - 0.30 + PinWidth/2), \
+ mm2mils100(-2.5 + pin * PinSpacing), \
+ mm2mils100(-Overall/2 + 0.55 - PinWidth/2), \
+ mm2mils100(-2.5 + pin * PinSpacing), \
+ mm2mils100(PinWidth), \
+ mm2mils100(0), \
+ mm2mils100(PinWidth + MaskAdd), \
+ '"pin%i"' % (12+pin), '"%i"' % (12+pin), '0x0100]'
+
+print ' ElementArc[',\
+ mm2mils100(-3.2), \
+ mm2mils100(3.2), \
+ '500 500 0 360 1000 ]'
+print ")"