AWC GP3 User manual

GP3 PC Analog/Digital I/O Kit
© 2010-2015 by AWC, All Rights Reserved
AWC
http://www.awce.c m
v1.6 15 April 2015
For the latest documentation see http://www.awce.com/doclib.htm#gp3

Table of Contents
Overview..................................................................................................................................................................1
D cumentati n.........................................................................................................................................................1
If Y u Need Help.....................................................................................................................................................1
Details......................................................................................................................................................................1
Hardware..................................................................................................................................................................2
GP3X...................................................................................................................................................................2
GP3X Parts List..............................................................................................................................................2
C nstructi n N tes.........................................................................................................................................6
Raspberry PI-C mpatible N tes.....................................................................................................................7
Arduin -C mpatible N tes............................................................................................................................7
GPMPU28...........................................................................................................................................................8
GPMPU28 Parts List......................................................................................................................................8
GPMPU28 External C nnecti ns...................................................................................................................8
GPMPU40.........................................................................................................................................................10
GPMPU40 Parts List....................................................................................................................................10
GPMPU40 C nnecti ns...............................................................................................................................11
GPMPU40 Edge C nnect r.........................................................................................................................12
Final Check ut..................................................................................................................................................13
S ftware.................................................................................................................................................................13
Reference...............................................................................................................................................................16
Quick Reference.....................................................................................................................................................20
Additi nal Pr t type Space (“Wings”)..................................................................................................................21
Specificati ns.........................................................................................................................................................22
Schematic (GP3X).................................................................................................................................................23
Schematic (GPMPU28).........................................................................................................................................24

Overview
The GP3 is the easiest way t interface a PC t the real w rld. Y u can als devel p using y ur PC and then let
the GP3 sense and c ntr l the real w rld n its wn. This kit pr vides a hardware interface that all ws y u t
easily m nit r and c ntr l anal g and digital circuitry. Features include:
•8 general purp se I/O lines (digital input/ utput with special features like PWM and pulse utput)
•5 10-bit A/D inputs
•1 hardware PWM utput ( perates c ntinu usly)
•1 hardware c unter input ( perates c ntinu usly)
•1 LED under s ftware c ntr l
•True RS232 fr m nb ard 5V supply
•EEPROM f r st ring c nfigurati n r serial numbers
•Efficient c ntr l via serial pr t c l (57600 baud) r use supplied libraries f r C, C++, Visual Basic, Java,
Linux, etc.
Documentation
To ensure you have the latest documentation, please check online (http://www.awce.com/doclib.htm#gp3
for the latest versions and updates.
If You Need Help
If y u require assistance, please feel free t c ntact us. The best way t get supp rt is via ur FAQ system
(http://www.awce.c m/faqs). Be sure t check ut ur Web page f r updates at www.al-williams.c m/awce.
Details
The GP-3 can be c nstructed n ne f several base b ards:
1. The GPMPU28 – This small f rm fact r b ard fits nearly anywhere. C nvenient t plug int a
s lderless breadb ard.
2. The GPMPU40 – Larger and m re cust mizable than the GPMPU28. Simple t plug int a s lderless
breadb ard r c nnect in a fixed installati n.
3. The GP3X – This b ard ffers the ultimate cust mizati n capabilities f r the GP3.
There are 6 secti ns n any GP3 system:
•CPU – The CPU chip c ntains the firmware and mem ry f r the system. N te that a jumper input selects
if the GP3 executes it nb ard s ftware r if it accepts c mmands fr m a PC. On the GPMPU28 this
jumper is n the edge c nnect r. On the GP3X and GPMPU40 there is a dedicated jumper.
•Cl ck – The CPU requires a 20MHz scillat r. On the GPMPU28 b ard a three pin 20MHz res nat r is
required. The ther b ards n rmally take the same res nat r, but can accept a crystal and ass ciated
capacit rs.
•C mmunicati ns – By default, all versi ns f GP3 use RS232 c nnecti ns and will w rk with m st
USB t serial adapters. In additi n, the GP3X b ard has pr visi ns f r a USB daughter b ard r cable. It
is als p ssible t fit the USB hardware in a GPMPU40 b ard.
•P wer – The GP3 requires a 5 v lt regulated supply. Y u can c nnect an external regulated supply r use
the nb ard p wer system n any f the base b ards. If using the USB daughter b ard/cable, the GP3X
can btain p wer fr m the USB p rt.
•Reset – The CPU requires a pull up resist r n the reset pin. In additi n, a jumper r switch can be used
t manually reset.
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•Interface – The wh le p int t the GP3 is t interface t the utside w rld. Each b ard has a variety f
meth ds t c nnect it t the utside w rld.
The remainder f this manual will be divided int tw maj r parts: Hardware and S ftware. The Hardware
p rti n will discuss each b ard pti n in turn. Y u sh uld n t need t read the secti ns that d n t apply t the
b ard y u've selected. The S ftware p rti n deals with h w t c mmunicate and c ntr l the GP3 and applies t
all versi ns f the hardware.
Hardware
Please select the secti n bel w that applies t the base b ard supplied with y ur kit. If y ur kit was pr vided
assembled, y u may still wish t read the secti ns bel w t get a better understanding f the lay ut f the b ard.
GP3X
There are several variati ns f r the GP3X. If y u are using the Arduin r Raspberry versi n, many f the parts
n the b ard are n t p pulated as they are n t needed. Y u sh uld read and understand the GP3X build
instructi ns and then refer t the specific secti ns f r y ur particular variant t learn the details ab ut it.
GP3X Parts ist
Designator Description
C1-C4 1 uF capacit r (n t included with USB kit)
C5 0.1 uF capacit r
C6 330 uF capacit r (n t included with USB kit)
C7, C8 Opti nal. Capacit rs matched t X1 if needed.
D1A 5V LED
D1B 5V r regular LED (see pti ns)
IC1 GP3 CPU and 28 pin narr w s cket
IC2 MAX232 (n t included with USB kit)
IC3 7805 (n t included with USB kit)
IC4 USB cable r daughter b ard (UB232R); If daughterb ard used, includes tw 4 pin s cket strips and is
usually m unted n b tt m side f b ard. If n t used, IC4 can be used f r ther purp ses (see pti ns);
J1, J2 C nnect rs n .2” centers; usually installed n b tt m f b ard, but may be installed n t p if preferred
(see pti ns). Standard kit c mes with pin headers (which may be n .1” centers; rem ve extra pins
with pliers) r pti nal screw terminals which interl ck t make 12 p siti n c nnect rs.
J3 DB9 female (right angle, sh rt reach; n t included with USB kit)
JP1, JP2 N rmally n thing is c nnected here. Y u can cut traces between the centers and rewire the digital and
anal g I/O t y ur liking (see pti ns)
R1 10K resist r
R2 Dr pping resist r f r D1B, if required
X1 20Mhz ceramic res nat r (three terminal) r 20Mhz crystal ( uter pins nly) with matching C7 and C8
installed. F r Pi-c mpatible versi n, the res nat r is 10MHz.
Reset ( pti nal) 5mm tact switch (pins 1 and 3) r 2 pin header (pins 1 and 2)
Pg Run 3 pin header and jumper
+V C axial p wer jack ( pti nal; see text)
E pty By default ICSP, JP1, JP2, R2 D1B, C7, C8, IC4, IC4A, IC4B, TTLSER, DTEDCE, and +5V/GND
header (t the right f JP2) are empty. See cust mizati n f r m re inf rmati n n h w these parts f
the b ard may be used.
The GP3X b ard is highly flexible. Each f the GP3 secti ns has several pti ns f r cust mizati n. Y u sh uld
plan the pti ns that will meet y ur needs bef re starting c nstructi n.
•CPU – The CPU sh uld be s cketed, alth ugh this is n t strictly necessary. The 3 pin header marked
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Pgm Run (near JP1) all ws y u t install a header t switch the b ard between the m de where it
accepts c mmands fr m the PC (Pgm) r executes its internal pr gram (Run). N rmally y u will install
a 3 pin header in this l cati n and a jumper will select between the tw pti ns. H wever, if y u are
certain y u nly want t perate the b ard in ne m de, y u can hard wire the jumper.
•Cl ck – By default, kits based n the GP3X b ard use a 20MHz ceramic res nat r that includes
capacit rs. H wever, the same s cket can accept a regular res nat r r a crystal in which case y u'll
need t install C7 and C8 with the capacit rs required. In additi n, an 8 pin DIP scillat r (20MHz)
c uld be installed at IC4 and its utput fed int pin 9 f IC1.
•C mmunicati ns – By default, the GP3 c mmunicates via a DCE RS232 p rt f rmed by J3, IC2, and
C1-C4. A DCE p rt mates via a straight cable t DTE p rts such as th se c mm nly f und n a PC.
H wever, there are several pti ns available.
First, y u can rewire the p rt s it selectable between DTE and DCE. Near J3 there is a 2x4 pin header
marked DTEDCE. The PC b ard has traces running acr ss the pins. Y u can carefully rem ve the traces
between each f the f ur pairs f pins using a h bby knife r raz r (the traces are n the t p side f the
b ard – the side with the silk screen markings). Then y u can install a 2x4 pin header int the h les. If
y u place 4 jumpers acr ss the pins (making the same c nnecti ns as the traces did) the p rt will be
DCE. H wever, if y u place the jumpers at right angles, the p rt will be DTE suitable f r c nnecti n t ,
f r example, a m dem. H wever, if wired as DTE, y u'll need a cr ss cable (s metimes called a null
m dem cable) t c nnect t a PC f r pr gramming. The figure bel w sh ws h w the DTEDCE jumpers
can be c nnected.
If y u are c nnecting the GP3 t a n n-RS232 device like a micr c ntr ller, y u can use the TTLSER
pins and rem ve IC2. The pins are:
1 – Handshaking in t GP3 (RTS)
2 – Handshaking ut t GP3 (CTS)
3 – Transmit fr m PIC (TX)
4 – Receive fr m PIC (RX)
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DCE (default)
DTE
DCE (default)
DTE

Recent GP-X b ards use a special USB cable f r c mmunicati ns. The cable has six wires. Y u may
want t s lder the cable t the t p side f the b ard r the b tt m, depending n h w y u plan t m unt
the finished unit. The table bel w sh ws where each wire is c nnected by c l r:
Color Function GP3X connection
Black Gr und GND (any f the GND pins near the A4 pin n J1)
Red +5V +5V (any f the +5V pins near the A4 pin n J1); mit if using seperate p wer
supply
Yellow RTS TTLSER pin 1
Blue CTS TTLSER pin 2
White TX TTLSER pin 3
Green RX TTLSER pin 4
After testing the GP3-X, y u may want t use a small zip tie t strain relief the cable by passing the zip
tie thr ugh the tw large h les in the unused J3 f tprint, ensuring that the USB cable is encircled by the
zip tie. Pull the tie tight t l ck the cable d wn t the b ard.
Older GP3-X b ards used a daughterb ard f r USB c mmunicati ns. The IC4 s cket can accept this
USB daughter b ard (part number UB232R). N rmally this b ard is fitted under the b ard using the
s cket strips supplied with the daughter b ard. The pins are s ldered n the t p side f the b ard (the
side f the b ard with the silk screen markings). Because f the unusual pin spacing f the daughter
b ard, ne r w f pins g es int IC4's pins 1-4. The ther r w g es int the r w f h les marked IC4B
that are nearest t IC4. The USB p rt sh uld face the edge f the b ard that h lds J1.
N te that because the daughter b ard is installed under the b ard, the pin numbers are reversed. That is,
pin 1 f the m dule c rresp nds t IC4 pin 8 and the m dule's pin 8 will c nnect t IC4 pin 1. With the
USB p rt n the underside f the b ard, it is usually a g d idea t use spacers r b lts in the f ur
c rner m unting h les t f rm “feet” f r the b ard s it d es n t rest n the USB interface.
The c nnecti ns between the daughter b ard and the rest f the b ard appear in the table using the IC4
pin numbers and the m dule pin numbers f r reference. If y u wish t p wer the b ard fr m its wn
p wer supply r fr m an external 5V s urce, d n t c nnect pin 2 f the USB b ard. H wever, if y u
wish t perate the b ard fr m the USB p wer supply y u can c nnect pin 2 t ne f the h les near JP2
marked +5V and mit IC2 and C6. The jumper n the daughter b ard sh uld be c nnected between pins
1 and 2 s that the b ard perates n 5V instead f 3.3V.
IC4 pin # USB232 Pin # GP3X connection
81 Gr und
72 +5V (if USB p wer desired; n c nnecti n if using separate p wer supply)
63 TTLSER-2
54 TTLSER-1
27 TTLSER-3
18 TTLSER-4
N te that it is p ssible t s cket IC2 and the USB m dule s that the b ard can perate in either m de.
With the p wer rem ved, simply install either IC2 r the USB m dule as desired. T switch the b ard t
use the ther type f c mmunicati ns, rem ve the p wer. Then rem ve either IC2 r the USB m dule
and install the ther unit.
•P wer – There are several pti ns t p wer the GP3. The nly actual requirement is a regulated 5 v lt
(5V) supply. Feeding such a regulated v ltage int any f the pins n J1 r J2 marked 5V (and gr und
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n any f the pins marked –) is sufficient t p wer the b ard (with all I/O quiescent, the b ard draws
r ughly 11 t 15 mA).
If y u prefer, y u can install the regulat r (IC3) and C6 and feed a higher v ltage (usually 8 t 12V) int
V+ n J2. Then the b ard will pr duce 5V f r itself and pr vide it at the 5V p ints n J1 and J2. There
are als h les where y u can tap ( r supply) 5V and gr und near JP2 marked +5V and GND.
If y u wish t use a c axial p wer jack, ne is included alth ugh its use is pti nal. The jack has three
pins, tw that line up and ne that is ffset. Using pliers, bend the ffset pinup against the b dy f the
jack. This pin is the same as the pin nearest the pen end f the c nnect r and it is cust mary t use this
pin f r gr und. The bent pin can be used as a gr und p int f r testing r it can be clipped.
The jack can be placed against the – and V+ pins f J2 al ng the t p side f the b ard. The pins will line
up with the h les and y u can tack s lder the pins (see Figure bel w). In this c nfigurati n, a standard
DC “wall wart” with the sleeve gr unded (the center pin sh uld have between 8 and 12 v lts) will p wer
the nb ard regulat r.
•Reset – The chip requires a 10K resist r at R1. In additi n, the RESET header near IC3 can
acc mm date a 2 pin header (between pins 1 and 2) s a jumper can reset the b ard. By default, the
GP3X kits, h wever, have a 5mm tact switch that can install in the h les (pins 1 and 3) t pr vide a true
reset switch.
•Interface – The primary external access t the b ard's functi ns is via J1 and J2. The markings n the
b ard explain what each pin d es. The 4 c rners (marked with –) are gr und p ints. There is an ther
gr und n J1 right after the anal g channels. The anal g channels are marked A0 t A4. The ther pins
n J1 are the hardware c unter (CT), the hardware PWM utput (PW), the LED utput (LED), and a
c nnecti n t the 5V supply rail (+5). J2 als has a 5V supply rail c nnecti n, an input t the v ltage
regulat r (+V), and the digital pins (D0 t D7).
You can install headers in these locations either on the top of the board or the bottom (the b tt m is
handy f r plugging int s lderless breadb ards). In additi n, y u can use standard “screw terminals”
which c me in interl cking bl cks f 2 r 3 terminals, r use any ther type f 12 pin c nnect r with
0.2” spacing. If y u rdered the screw terminals and install them on the bottom of the board
(s ldering them n the same side as the silk screen) they will f rm “feet” that will h ld the b ard up
which is handy and als leave the ther c mp nents n the b ard m re accessible. H wever, y u can
als install them n the t p f the b ard if y u prefer. In particular, if y u install the USB daughter b ard
(which m unts n the b tt m) y u may want t keep the pins n the t p. The ch ice between t p and
b tt m is purely ne f pers nal preference – the circuit d esn't care either way.
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The anal g and digital pins r ute thr ugh JP1 and JP2. If y u wish, y u can cut the traces between the
secti ns f JP1 (digital) r JP2 (anal g) and rer ute the signals. F r example, y u might put a series
resist r between the h les t limit current. Or y u c uld r ute a wire fr m an anal g input t an p-amp
in the spare IC4 s cket and then back fr m the p-amp t the GP3's CPU. N te that n JP2, the 5th pin
(near J1's A3) is n t c nnected thr ugh and nly c nnects t an unused GP3 pin.
IC4 is available f r use with any circuitry y u might want t add unless y u are using it f r the USB
daughter b ard. An p amp, a temperature sens r, a s lid state relay, a DIP switch, r anything else y u
can arrange t fit in an 8 pin DIP fact r can be placed at IC4. The IC4A and IC4B h les c nnect t IC4
t pr vide places y u can c nnect y ur circuitry t the b ard. In additi n, there are c nvenient h les that
carry +5V and gr und nearby f r y ur use.
The LED utput is br ught ut t JP1 and als t D1A which n rmally takes a 5V LED. Y u can als fit
D1B as a n rmal LED with an appr priate dr pping resist r at R2. It is p ssible t use b th LEDs if the
utput current f the GP3 pin is n t exceeded (in which case b th LEDs will light r extinguish
t gether). An ther pti n is t install a 5V LED at D1B and mit R1. Then y u can use the R1 pad with
the circle ar und it as a c nnecti n p int. F r example, y u might wire fr m the circle pad f R1 t ne
f the JP1 digital c nnecti ns t get a sec nd LED utput. It is n t necessary t install either D1A r
D1B f r the GP3's perati n.
Once y u have decided n the pti ns y u wish t use, y u can assemble the b ard. In general it is best t start
with the “l w” c mp nents first. IC1's s cket and IC2, f r example are easiest t install first. Then y u can
install discrete c mp nents like the smaller capacit rs, resist rs, and LEDs. Large c mp nents like the
c nnect rs, C6, and IC3 sh uld be installed last.
Construction Notes
•If y ur kit is supplied with tw 24 pin .1 inch headers simply rem ve every ther pin with pliers s
that the headers fit in the J1 and J2 sl ts.
•C1-C4 have p larity markings but it is n t necessary t use electr lytic capacit rs. If y ur kit is
supplied with ceramic capacit rs f r C1-C4 y u can ign re the p larity markings n the b ard.
•C6, the LEDs, and the ICs are the nly devices that y u have t be careful t bserve the rientati n
marked n the b ard. C6 sh uld have its + r – lead clearly marked and the + side is marked n the
b ard. The l nger lead f LEDs will g in the h le marked with the plus sign.
•IC1 and IC2 sh uld be riented as sh wn n the silk screen. The silk screen f r IC3 sh ws a thick
bar near the edge which is the back f the package (the side with ut the part markings).
•Because IC4 is unc mmitted y u can install s mething in IC4 any way y u like (including n the
back side f the b ard) as l ng as y u d the rest f the wiring t IC4 t match.
•Alth ugh it is cust mary t put the b dy f the resist rs in the h le that has the white circle ar und
it, putting ne in backwards will n t affect circuit perati n.
•Alth ugh it is cust mary t put the ceramic res nat r r crystal s that the markings face away fr m
IC1, putting it backwards will n t affect circuit perati n.
•D n't f rget that JP1, JP2, IC4A, IC4B, and DTEDCE all have traces c nnecting pins “acr ss” fr m
each ther. If y u are making any m dificati ns that require these h les t be electrically separate
y u must use a h bby knife r raz r t carefully cut thr ugh the trace n the t p side f the b ard
that c nnects them. Y u sh uld check that y u have made the cut by using an hm meter bef re and
after the cut. Of c urse, be careful n t t cut ther parts f the b ard.
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Y u sh uld check y ur w rk bef re installing IC1 in its s cket. P wer the b ard up using y ur ch ice f
meth ds (9V t the +V pin n J2, 5V regulated t any f the +5V pins, r USB p wer) and verify that 5V
appears n the +5V c nnect r near JP2.
Next, pr ceed t the Final Check ut secti n bel w.
Raspberry PI-Compatible Notes
Important Note: Although the GP3X board has pins labeled +5V, when using the Raspberry PI-
compatible version, these pins are at 3.3V. It will n t hurt the GP3 t p wer it at 5V, but it may damage the
h st c mputer.
In additi n, all time-related measurements f r the Raspberry PI-c mpatible versi n are at 1/2 res luti n
c mpared t the n rmal GP-3 (h wever, the baud rate is still 57600 baud). S a c mmand that specifies time
millisec nds n a n rmal GP-3 will use 2mS units n the Raspberry PI-c mpatible versi n.
The PI-c mpatible b ard c ntains the f ll wing c mp nents: C5, D1, IC1 (and s cket), R1, and X1. In additi n
there is a 3 pin header and a 2 pin header. Screw terminals are n rmally supplied.
The b ard is assembled as usual, ign ring any parts n t supplied. A wire jumper must be put in the PGM/RUN
jumper g ing fr m PGM t the center pin. Y u sh uld als install a wire jumper (insulated) between pin 1 f the
TTLSER c nnect r t any gr und p int (pin 5 f the DB-9 c nnect r, J3, is handy).
The 3 pin header is placed in the TTLSER pins (pin 2-4) and the tw pin header is place in any f the 4 h les
marked +5V and GND near the A4 pin n the edge f the b ard. Place the header s that ne pin is in the +5V
h le (which is actually 3.3V) and the ther is in the GND h le.
T c nnect t the Pi, c nnect 3.3V fr m the Pi (pin P1-1) t the +5V pin n the GP3X. Als c nnect the gr und
(pin P1-6). Y u can d this via the 2 pin header installed r the screw terminals, as y u prefer (if y u plan t
nly use the screw terminals, y u d n't need t install the tw pin header).
C nnect the PI's P1-8 pin t the GP3X TTLSER pin 3 and P1-10 t TTLSER pin 4. This enables serial
c mmunicati ns with the Pi.
The serial p rt n the Pi is used as the system c ns le. This has t be disabled in rder t free the p rt f r use
with the GP3. Edit /etc/inittab and find the line that c ntains /sbin/getty and ttyAMA0. Using a text edit r (and
y ur r t l gin) place a # sign at the start f this line and save the file. Y u will have t reb t the Pi t free the
serial p rt. If y u ever want t enable the c ns le, edit the file again and rem ve the # sign.
F r s ftware, see http://www.awce.c m/gp3pi.htm f r the latest s ftware and dem s.
Arduino-Compatible Notes
The Arduin -c mpatible versi n nly uses the f ll wing parts: C5, D1A, IC1 (and s cket), R1, and X1. In
additi n, there is a 3 pin header and a 2 pin header. Screw terminals are n rmally supplied.
The b ard is assembled as usual, ign ring any parts n t supplied. A wire jumper must be put in the PGM/RUN
jumper g ing fr m PGM t the center pin. Y u sh uld als install a wire jumper (insulated) between pin 1 f the
TTLSER c nnect r t any gr und p int (pin 5 f the DB-9 c nnect r, J3, is handy).
The 3 pin header is placed in the TTLSER pins (pin 2-4) and the tw pin header is place in any f the 4 h les
marked +5V and GND near the A4 pin n the edge f the b ard. Place the header s that ne pin is in the +5V
h le (which is actually 3.3V) and the ther is in the GND h le.
T c nnect t the Arduin , y u must c nnect p wer t the 2 pin header r the terminals marked +5 and –
(usually fr m the Arduin ; if y u use a separate 5V supply, be sure the Arduin and the GP3 share a c mm n
gr und). The serial p rt c nnects t pin 3 and 4 f the TTLSER c nnect r. Depending n y ur sketch, y u may
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