2 # Copyright 2022 by Bdale Garbee <bdale@gag.com>. GPLv3
4 # emit PCB footprint for Atmel VQFN-48 package used by SAM21D
7 # dimensions in mm from
8 # atmel/samd21/SAM_D21_DA1_Family_Data_Sheet_DS40001882H-2580554.pdf
12 RowSpacing = 6.9 # C1 / C2
15 GndSquare = 5.25 # X2 / Y2
17 PinClearance = 2 * (PinSpacing - PinWidth)
19 # ATMEL specifies 120-150 microns between pad and solder mask
20 # AT88RF1354 Appplication note .. should be good here too?
22 PinResist = PinWidth + (2 * 0.07)
24 # we're going to use the 1/100 of a mil fundamental unit form
27 return int( mm / 25.4 * 1000.0 * 100.0 + 0.5 )
29 print '# author: Bdale Garbee'
30 print '# email: bdale@gag.com'
31 print '# dist-license: GPL 3'
32 print '# use-license: unlimited'
34 print 'Element[0x0 "vqfn-48" "" "" 0 0 0 0 0 100 0x0]'
43 # mm2mils100(GndSquare), \
44 # mm2mils100(PinClearance), \
45 # mm2mils100(PinResist), \
46 # '"pin49" "49" "square,nopaste"]'
48 ## vias in the ground pad under the chip
49 #for viarow in range (-1,1):
50 # for viacol in range (-1,1):
52 # mm2mils100(1.8 * viacol * CoreSquare / 3 + .9 * CoreSquare/3), \
53 # mm2mils100(1.8 * viarow * CoreSquare / 3 + .9 * CoreSquare/3), \
58 # '"pin17" "17" 0x0002]'
60 ## break pad under chip into a grid to control the resist and paste masks
64 #for viarow in range (-1, 2):
65 # for viacol in range (-1, 2):
66 # if (viarow in (-1, 1)) and (viacol in (-1, 1)):
67 # # copper sub-square with resist over vias
69 # mm2mils100(viacol * CoreSquare / blocks), \
70 # mm2mils100(viarow * CoreSquare / blocks), \
71 # mm2mils100(viacol * CoreSquare / blocks), \
72 # mm2mils100(viarow * CoreSquare / blocks), \
73 # mm2mils100((CoreSquare)/blocks), \
76 # '"pin17" "17" "square,nopaste"]'
78 # # copper sub-square without resist
80 # mm2mils100(viacol * CoreSquare / blocks), \
81 # mm2mils100(viarow * CoreSquare / blocks), \
82 # mm2mils100(viacol * CoreSquare / blocks), \
83 # mm2mils100(viarow * CoreSquare / blocks), \
84 # mm2mils100((CoreSquare)/blocks), \
86 # mm2mils100((CoreSquare)/blocks), \
87 # '"pin17" "17" "square,nopaste"]'
88 # # copper spot to control paste mask generation
90 # mm2mils100(viacol * CoreSquare / blocks), \
91 # mm2mils100(viarow * CoreSquare / blocks), \
92 # mm2mils100(viacol * CoreSquare / blocks), \
93 # mm2mils100(viarow * CoreSquare / blocks), \
96 # mm2mils100((CoreSquare)/blocks), \
97 # '"pin17" "17" "square"]'
100 for pin in range (1,13):
102 mm2mils100((-6.5 + pin) * PinSpacing), \
103 mm2mils100(-RowSpacing/2 - PinHeight/2 + PinWidth/2), \
104 mm2mils100((-6.5 + pin) * PinSpacing), \
105 mm2mils100(-RowSpacing/2 + PinHeight/2 - PinWidth/2), \
106 mm2mils100(PinWidth), \
107 mm2mils100(PinClearance), \
108 mm2mils100(PinResist), \
109 '"pin%i"' % (37-pin), '"%i"' % (37-pin), '0x0000]'
112 mm2mils100((-6.5 + pin) * PinSpacing), \
113 mm2mils100(RowSpacing/2 - PinHeight/2 + PinWidth/2), \
114 mm2mils100((-6.5 + pin) * PinSpacing), \
115 mm2mils100(RowSpacing/2 + PinHeight/2 - PinWidth/2), \
116 mm2mils100(PinWidth), \
117 mm2mils100(PinClearance), \
118 mm2mils100(PinResist), \
119 '"pin%i"' % pin, '"%i"' % pin, '0x0000]'
122 mm2mils100(-RowSpacing/2 - PinHeight/2 + PinWidth/2), \
123 mm2mils100((-6.5 + pin) * PinSpacing), \
124 mm2mils100(-RowSpacing/2 + PinHeight/2 - PinWidth/2), \
125 mm2mils100((-6.5 + pin) * PinSpacing), \
126 mm2mils100(PinWidth), \
127 mm2mils100(PinClearance), \
128 mm2mils100(PinResist), \
129 '"pin%i"' % (36+pin), '"%i"' % (36+pin), '0x0000]'
132 mm2mils100(RowSpacing/2 - PinHeight/2 + PinWidth/2), \
133 mm2mils100((-6.5 + pin) * PinSpacing), \
134 mm2mils100(RowSpacing/2 + PinHeight/2 - PinWidth/2), \
135 mm2mils100((-6.5 + pin) * PinSpacing), \
136 mm2mils100(PinWidth), \
137 mm2mils100(PinClearance), \
138 mm2mils100(PinResist), \
139 '"pin%i"' % (25-pin), '"%i"' % (25-pin), '0x0000]'
141 print ' ElementArc[',\
142 mm2mils100(-Overall/2 - PinWidth), \
143 mm2mils100(Overall/2 + PinWidth), \
144 '500 500 0 360 1000 ]'