You should check your work before installing IC1 in its socket. Power the board up using your choice of
methods (9V to the Vin connector or 5V regulated to JP1-11) and verify that 5V appears either at JP1-11 or
another 5V test point (e.g, the exposed lead of R1 nearest IC3).
Next, proceed to the Final Checkout section below.
GPMPU40
GPMPU40 Parts List
Designator
Description
C1-C4
1 uF capacitor
C5
0.1 uF capacitor
C6
330 uF capacitor
C7, C8
Optional. Capacitors matched to X1 if needed.
D1
5V LED
IC1
GP3 CPU and 28 pin narrow socket; install so pin 1 matches pin 1
IC2
40 pin footprint; used for wiring connections in this case
IC3
MAX232
IC4
7805
IC5 (not marked)
An 8 pin socket can be placed so pin 1 matches pin 17 of IC1. An MCP602 may be supplied (see text).
This socket is not wired to anything by default so you can place anything you wish here (or nothing).
JP1, JP2
Forms one 40 pin connector with JP1-1 being pin 1 and JP2-1 being pin 21. These are normally
installed on the bottom of the board so the board can plug into a solderless breadboard. However, it is
possible to install on the top side of the board or use different connectors on .1 inch centers.
J1
DB9 female (right angle; short reach)
R1
10K resistor
R2 (not marked)
Dropping resistor for D1, if required. LED supplied does not require R2.
X1
3 pin 20MHz resonator (supplied) or 20MHz crystal with matching capacitors at C7 and C8
Reset
(optional) 2 pin header for reset jumper
Pgm Run (not
marked)
3 pin header and jumper
Vin/J2
9V battery snap or optional coaxial power jack
The GPMPU40 board is not specifically designed for the GP3 – it is simply a general purpose board and you
can read more about it in the GPMPU40 manual (see
http://www.awce.com/doclib.htm#GPMPU40
). The goal is
to essentially duplicate the GP3X or GPMPU28 schematics (at the end of this manual) on the board.
Building the GPMPU40 version of the GP3 requires you to install parts and then wire the different areas of the
board together (see table below). You can also customize the board in several ways.
The 28-pin IC socket goes in the IC1 footprint with pin 1 aligned. If you wish to use the optional 8 pin socket,
place it in IC1 also with pin 1 of the socket lined up with pin 17 of the footprint.
Other required components for the CPU are X1 and R1. Note that X1 is normally a 20MHz 3 pin resonator. If
you use a 2 pin resonator or a crystal you'll need matching capacitors (C7 and C8) depending on the crystal you
select. R1 is the reset resistor and you should also install a 2 pin header at the RESET holes unless you prefer to
wire an external switch to this port (not supplied).
If you are using RS232 (the default for this board) install J1, C1-C4, and IC3. It is possible to connect a
UB232R or other USB to serial board into the spare area under IC1 (the optional 8 pin socket).
The board can be powered by a 5V regulated supply (connected to the Vcc holes or the 5V connector on the
edge). You can also install IC4 and C6 to provide power on board. In this case you need to supply 8-12V on the
-10-
