Printed Circuit Board Design for PICAXE-20X2

[lbenson]

Call it jumping the gun. No testing on breadboard; no chip even available to be purchased. Because of the chip layout, anyone who has a 20M design automatically has a 20X2 design. Similarly, anyone who has a 14M design has 14/20ths of a 20X2 design. As luck would have it, on Saturday I sent my latest 14M design for my wireless house monitoring system -- http://www.picaxeforum.co.uk/showthread.php?t=11908&highlight=picaxe* -- to ExpressPCB to be made up, all unknowing that the 20X2 would be announced on Monday. But the 14M, as versatile as it is, has always been lacking--especially in code space to handle the number of pins, but also because it doesn't support i2c or serin timeout. And now, the 20X2--a little bigger footprint--solves the problems. So I modified my PCB design and have sent off for another set of boards. Hope Microchip is prompt in getting the chips to Rev-ed.

Thanks, Rev-ed, for the very pleasant surprise.

Legs Pins       Connected to
 1   +V         H1
 2   Serial In  H2 (programming, serrxd)
 3   C7         T4 (3-pin; opt. pullup, down)
 4   C6         SW1 (pushbutton)
 5   C5         T3 (3-pin; opt pullup)
 6   C4         T2 (3-pin; opt. pullup, down)
 7   C3         T1 (3-pin; opt pullup)
 8   C2         n.c.
 9   C1         Voltage divider for battery voltage ADC
10   C0         HSer (hardware serial out)
11   B7         Hi2c, hHI2c2 (4-pin; hi2c scl, pullup) 
12   B6         HSer (hardware serial in)
13   B5         Hi2c, hHI2c2 (4-pin; hi2c sda, pullup)
14   B4         O4 (3-pin)
15   B3         O3 (3-pin)
16   B2         O2 (3-pin)
17   B1         Voltage divider from O1 (3-pin) or link+pulldown
18   B0         H3 (3-pin, e.g., 315mHz xmitter)
19   Serial Out H2 (programming, sertxd, LED1)
20   0V         H1

The board is about an inch and a half by an inch and a quarter.