EVTV GEVCU User manual

Operation*Manual*GEVCU*5.22*August*2015*
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Generalized Electric Vehicle Control Unit
GEVCU
Version 5.22
Copyright 2013. EVTV LLC

Operation*Manual*GEVCU*Version*5.20********November*2014*
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LEGAL DISCLAIMER
This!manual!describes!a!hardware!device!produced!by!EVTV!Motor!Werks!LLC.!!The!Generalized!
Electric!Vehicle!Control!Unit!or!GEVCU!is!an!experimental!educational!device!designed!to!allow!
students!and!enthusiasts!to!explore!and!learn!about!electric!vehicle!control!issues!in!automotive!
development!–!particularly!using!drive!train!components!used!by!automotive!manufacturers.!
!
The!device!in!and!of!itself!performs!no!particular!or!specific!function!and!is!not!designed!for!
commercial!or!automotive!use.!!!
!
It!comes!preloaded!with!one!of!many!versions!of!the!GEVCU!open!source!software!project!available!
at!http://github/collin80/GEVCU.!!This!software,!created!entirely!by!enthusiasts!outside!of!the!
control!of!EVTV,!!can!be!downloaded!as!source!code!in!its!latest!versions,!modified!by!anyone!
anywhere,!including!the!end!user!or!owner!of!this!hardware!device,!for!any!reason!or!at!whim,!and!
installed!on!this!hardware!and!essentially!embodies!the!entire!functionality!of!the!device.!
!
As!such,!EVTV!Motor!Werks!has!no!control!over!what!the!device!can!do,!what!it!is!used!for,!how!well!
or!poorly!it!does!it,!or!why.!!EVTV!Motor!Werks!disclaims!any!liability!arising!from!the!purchase!and!
use!of!this!hardware!and!makes!no!claim!of!fitness!for!any!particular!purpose.!
!
The!GEVCU!hardware!is!offered!solely!for!the!educational!use!of!the!purchaser.!!Purchasers!of!this!
particular!offering!of!the!open!source!GEVCU!hardware!agree!to!defend!and!hold!harmless!EVTV!
Motor!Werks!from!any!claims!by!any!party!arising!from!their!purchase!and!use!of!the!GEVCU!device.!
!
While the source code and hardware design of the GEVCU is entirely open source, this
manual is copyright 2013, EVTV LLC and all rights are reserved.
!
This!document!is!intended!to!generally!represent!the!GEVCU!hardware!sold!and!distributed!by!EVTV!
specifically.!!It!reflects!the!software!installed!on!the!GEVCU!hardware!at!the!time!of!shipment.!!
Obviously,!if!other!software!!or!modified!software!is!loaded!onto!the!GEVCU!hardware,!or!indeed!if!
the!software!is!modified!by!the!end!user!to!provide!other!functions,!the!printed!document!and!the!
device!and!its!software!would!naturally!be!in!conflict.!!This!conflict!could!potentially!pose!certain!
safety!issues!to!the!end!user.!
!
It!is!both!foreseeable!and!intended!that!other!entities!will!also!produce!alternate!GEVCU!hardware!
and!other!forks!or!versions!of!the!GEVCU!software.!!Indeed!this!is!already!the!case.!!Those!entities!
should!produce!their!own!original!documentation!illustrating!how!THEIR!version!actually!works!at!
the!time!they!shipped!it.!!And!they!are!specifically!precluded!by!statute!from!distributing!THIS!
document!!or!any!part!of!it!with!alternate!hardware!and/or!software!designs.!
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Table of Contents
1. Introduction 4
2. Specifications 7
3. Wiring and Connections 11
4. Serial Port Interface 18
5. Module Selection 21
6. Precharge Considerations 23
7. Throttle Calibration and Mapping 29
8. Brake Calibration and Mapping 36
9. Power Values 40
10. Analog Inputs 42
11. Digital Inputs 44
12. Digital and Analog Outputs 47
13. Cooling Control – A Digital Output Example 49
14. Wireless Configuration 53
15. CAN bus Communications and OBDII 63
16. CAN Control of Input and Outputs 68
17. Updating GEVCU Software 72

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1 Introduction
For!40!years!and!more,!individual!tinkerers!and!innovators!have!been!modifying!existing!
automobiles!to!electric!drive!and!often!building!electrically!powered!vehicles!from!scratch.!
!
The!early!“controllers”!that!evolved!to!replace!simple!switching!and!resistive!controls!to!control!the!
speed!of!the!driver!motors!were!mostly!pulse!width!modulated!(PWM)!devices!to!provide!an!
averaged!DC!signal!to!a!series!DC!motor.!!These!simple!chopper!voltage!control!devices!were!
generally!referred!to!as!“controllers”!and!translated!driver!input!from!“controls”!such!as!the!
accelerator!pedal,!ignition!switch,!and!brake!to!this!motor!driving!voltage!to!control!its!speed!and!
direction!–!and!consequently!the!vehicle.!
!
There!are!of!course!many!other!types!of!motors!such!as!
separately!excited!DC!motors,!brushless!DC!motors,!
permanent!magnet!motors!and!AC!induction!motors.!!Most!
of!these!polyphase!motors!require!3!phase!“inverters”!to!
convert!the!DC!power!of!the!battery!pack!into!three]phase!
AC!drive!signals!varying!the!voltage!(for!torque)!and!
frequency!(for!speed)!of!the!power!to!the!motor!to!
accomplish!the!same!thing.!
!
Most!of!the!DC!“controllers”!received!the!inputs!directly!
by!wiring!from!the!sensors!or!controls!in!the!cars.!
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In!recent!years,!among!automobile!manufacturers,!the!use!
of!the!Bosche!Controller!Area!Network!(CAN)!protocol!has!
been!adopted!for!many!of!the!items!in!the!automobile,!including!the!internal!combustion!engine!–!
often!called!an!Engine*Control*Unit!or!a!Vehicle*Control*Unit!which!forms!the!central!computer!or!
“brains”!of!the!car.!!It!is!connected!to!various!sensors!and!controls!by!wire!but!communicates!to!
other!subsystems!of!the!vehicle!such!as!the!instrumentation,!ABS!system,!transmission,!!
environmental!system!using!this!CAN!bus!as!the!common!link.!
!
Automakers!have!eschewed!the!DC!motor!in!favor!of!either!permanent!magnet!AC!motors!or!AC!
induction!motors.!!And!the!“inverters”!developed!to!drive!these!were!interfaced!to!this!same!CANbus!
model!for!control!input.!
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Because!of!the!varying!nature!of!the!cars,!the!ECU!or!VCU!would!be!specifically!designed!for!THAT!
particular!make!and!model.!In!this!way!the!inverters!and!!AC!motors!can!be!somewhat!generic!to!
work!in!any!car.!!The!intelligence!moved!OUT!of!the!inverter!and!into!the!VCU,!which!contained!all!
the!vehicle!specific!information.!!
The!VCU!would!be!specifically!designed!and!software!specifically!written!for!that!vehicle.!!And!all!the!
particulars!for!that!make!and!model!would!reside!in!the!software!for!the!VCU.!This!was!hardcoded!
into!flash!memory!and!defined!the!operation!of!the!vehicle.!!No!end!user!input!or!options!were!
provided.!!Firmware!updates!or!changes!are!normally!accomplished!by!revising!the!code,!

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recompiling,!and!having!the!controller!reflashed!with!the!new!binaries!at!the!dealership!during!
normal!maintenance.!
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And!so!thousands!of!these!VCUs!could!be!flashed!when!built,!with!the!software!specific!to!that!
particular!vehicle.!
!
The!particular!VCU!would!of!course!be!completely!inappropriate!and!non!functional!in!any!other!
vehicle!make!or!model.!!
!
As!many!automakers!are!experimenting!with!product!introductions!of!plug]in!electric!vehicles!and!
hybrid!gasoline/electric!vehicles,!many!of!the!components!used!in!these!vehicles!are!becoming!
available!when!the!cars!are!salvaged!and!are!recycled!through!salvage!yards!and!such!online!
services!as!eBay.!
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As!such,!they!will!become!a!resource!to!individual!tinkerers!and!those!converting!existing!cars!to!
electric!drive.!!Fortunately,!most!are!somewhat!generic!and!almost!all!of!these!components!were!
designed!to!be!controlled!by!CANbus!signals!from!the!Vehicle!Control!Unit!that!came!with!the!
original!car.!
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It!would!be!a!serious!advantage,!to!have!a!more!generalized!vehicle!control!unit!that!could!produce!
these!CAN!commands!to!drive!existing!power!switching!inverters,!chargers,!dc]dc!converters!and!
other!equipment!gleaned!from!the!many!parts!available!in!salvage.!!But!to!be!truly!useful,!it!should!
allow!some!basic*configuration!by!the!end!user!allowing!these!conversions!to!modify!operation!of!
the!VCU!to!accommodate!THEIR!vehicle!without!the!need!to!entirely!rewrite!the!software!and!flash!
the!VCU.!!Just!change!a!handful!of!variables!specific!to!the!car.!
!
In!December!2012,!Jack!Rickard!of!Electric!Vehicle!Television!http://evtv.me!first!proposed!a!
program!to!develop!such!a!GENERALIZED!Electric!Vehicle!Control!Unit!or!GEVCU!using!the!then!
just!introduced!Arduino*Due!platform!with!an!84!MHz!32]bit!ARM!CORE3!processor.!!And!he!
elected!to!do!this!as!an!open*source!project!anyone!could!not!only!use,!but!modify!further!with!
regards!to!either!hardware!or!software!to!meet!their!own!particular!needs.!!
!
As!such,!the!GEVCU!could!serve!as!the!central!computer!or!“brains”!of!any!electric!car,!and!flexibly!
drive!ANY!available!inverters,!motors,!battery!management!systems,!throttles,!brakes,!sensors,!etc!in!
the!car.!!This!modular!approach!would!to!some!degree!commoditize!many!of!the!major!components!
of!the!vehicle,!while!the!specifics!were!held!in!a!central,!open!source!device!that!anyone!could!
change,!adapt,!and!extend!as!necessary.!
!
A!number!of!EVTV!viewers!began!contributing!code!and!hardware!designs!and!by!late!summer!
2013,!EVTV!first!drove!a!1974!VW!Thing,!with!a!Siemens!1PV5135!AC!induction!motor!and!
DMOC645!inverter!from!Azure!Dynamics,!all!entirely!controlled!by!the!GEVCU.!!It!featured!
controlled!regenerative!braking!on!both!throttle!and!brake,!a!controllable!precharge!procedure!for!
applying!power!to!the!DMOC,!and!control!of!the!cooling!fans!on!the!liquid!cooling!system.!
!
Along!the!way,!the!original!Arduino!Due!hardware!morphed!into!a!somewhat!more!hardened!
hardware!design!capable!of!surviving!the!automotive!environment,!while!retaining!the!full!
compatibility!with!the!Arduino!software!development!environment.!
!
A!selected!subset!!of!Arduino!input!and!output!pins!was!brought!out!to!a!single!weather!resistant!
AMPSEAL!35!pin!connector!for!example.!!Various!strategies!and!components!were!used!to!isolate!

Operation*Manual*GEVCU*Version*5.20********November*2014*
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the!inputs!and!outputs!from!the!multicontroller!chip!itself!to!“harden”!the!device!to!EMP!and!EMI!
and!the!noise!inherent!in!vehicle!12v!systems.!!But!the!essential!Arduino!programming!environment!
and!compatibility!were!retained.!
!
The!result!was!a!powerful!multicontroller!device!with!TWO!programmable!CAN!bus!channels,!
wireless!Internet!access,!a!variety!of!analog!and!digital!inputs!and!outputs,!and!beyond!the!ability!to!
reprogram!the!device!entirely!using!the!Arduino!IDE,!the!original!design!allows!the!end!user!to!
easily!configure!some!of!the!basic!aspects!of!throttle!and!brake!and!so!!forth!without!really!learning!
to!program!at!all.!
!
This!document!describes!the!use!and!configuration!of!the!!Generalized Electric Vehicle
Control Unit.!!The!multicontroller!hardware!allows!connection!of!the!basic!sensor!set!necessary!to!
drive!the!car!such!as!throttle!signals,!brake!signals,!ignition!signal,!and!control!the!basic!common!
outputs!such!as!brake!lights,!fuel!level,!rpm,!power!usage,!while!serving!in!the!central!role!of!
converting!these!inputs!to!CAN!messages!for!the!inverter!to!actually!drive!the!AC!motor!and!thus!the!
car.!
!
The!operation!of!this!device!can!be!modified,!within!fairly!narrow!constraints,!by!a!simple!
configuration!“menu”!style!input!that!non]programmers!can!access!and!make!changes!to,!in!order!to!
interface!the!VCU!to!the!particular!car!they!want!to!convert.!
!
Note!that!the!GEVCU!program!is!both!open!software!and!open!hardware!with!the!schematics!and!
board!layouts!published!for!all.!!As!such,!THIS!document!ONLY!applies!to!the!EVTV!produced!GEVCU!
hardware!and!the!software!preloaded!onto!it!before!shipment.!
!
This!document!will!be!updated!from!time!to!time!to!reflect!changes!in!hardware!or!software!that!
EVTV!adopts!in!their!release!of!the!product.!!But!by!necessity,!it!cannot!cover!changes!in!hardware!
or!software!made!by!other!parties!or!the!end!user.!!This!should!be!obvious.!!!
!
But!we!think!the!end!user!will!find!SOME!documentation!of!the!baseline!EVTV!shipped!version!
useful!as!a!starting!point.!
!
Because!of!these!variations,!this!manual!is!copyright!2013!EVTV!Motor!Werks!and!other!developers!
producing!hardware!and!software!variants!are!specifically!precluded!from!including!this!manual,!or!
any!excerpted!portion!thereof.!!Inevitably,!this!manual!will!not!properly!describe!those!variants.!
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Operation*Manual*GEVCU*Version*5.20********November*2014*
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2 Specifications
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Operation*Manual*GEVCU*Version*5.20********November*2014*
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Table&1.&AMPSEAL&35&Pin&Wire&Harness&Description&
&
Pin&&
Color&4.01&
Symbol&
Description&
1"
BLK"
VIN(+12V)"
Positive"Power"Supply"(Ignition"KEY)"
2"
BRN"
+12V"
Regulated"+12V"output"
3"
TAN"
DOUT0"
Digital"Output"No."0"
4"
VIO"
DOUT1"
Digital"Output"No."1"
5"
GRY"
DOUT2"
Digital"Output"No."2"
6"
YEL"
DOUT3"
Digital"Output"No."3"
7"
RED"
GND"
Ground"
8"
ORN"
GND"
Ground"
9"
BLU"
CAN0"HI"
CAN"High"Channel"0"
10"
GRN"
CAN0"LO"
CAN"Low"Channel"0"
11"
PNK"
CAN1"HI"
CAN"High"Channel"1"
12"
WHT"
CAN1"LO"
CAN"Low"Channel"1"
13"
BLK/RED"
GND"
Ground"
14"
BRN/BLK"
GND"
Ground"
15"
BLU/RED"
DOUT4"
Digital"Output"No."4"
16"
VIO/BLK"
DOUT5"
Digital"Output"No."5"
17"
GRY/BLK"
DOUT6"
Digital"Output"No."6"
18"
GRN/RED"
DOUT7"
Digital"Output"No."7"
19"
RED/BLK"
GND"
Ground"
20"
ORN/BLK"
AIN0"
Analog"Input"No."0"
21"
PNK/BLK"
AIN1"
Analog"Input"No."1"
22"
TAN/BLK"
AIN2"
Analog"Input"No."2"
23"
YEL/BLK"
AIN3"
Analog"Input"No."3"
24"
WHT/BLK"
+5V"
Regulated"+5V"output"
25"
BLK/RED/BLU"
+5V"
Regulated"+5V"output"
26"
BRN/BLK/RED"
+5V"
Regulated"+5V"output"
27"
BLU/BLK/RED"
+5V"
Regulated"+5V"output"
28"
VIO/BLK/RED"
+5V"
Regulated"+5V"output"
29"
GRY/BLK/RED"
GND"
Ground"
30"
GRN/BLK/RED"
GND"
Ground"
31"
RED/BLK/BLU"
GND"
Ground"
32"
ORN/BLK/RED"
DIN0"
Digital"Input"No."0"
33"
PNK/BLK/RED"
DIN1"
Digital"Input"No."1"
34"
TAN/BLK/RED"
DIN2"
Digital"Input"No."2"
35"
YEL/BLK/RED"
DIN3"
Digital"Input"No."3"
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"
"
"
"
"
"
Table&2.&Absolute&Maximum&Rating&
"
"
"
"
Parameter&
Symbol&
Value&
Units&
"
"
Supply"Voltage"
VIN(+12V)"
16"
V"
"
"
Regulated"+12V"output"
+12V"
1.5"
A"
"
"
Regulated"+5V"output"
+5V"
1*"
A"
"
"
Digital"Outputs"
DOUT0…"DOUT7**"
1.7"
A"
"
"
CAN"BUS"
CAN0"HI/LO;"CAN1"HI/LO"
–27"to"40"
V"
"
"
Analog"Inputs"
AIN0…"AIN3"
12"
V"
"
"
Digital"Inputs"
DIN0…"DIN3"
15"
V"
"
"
"
"
"
"
"
"
*Total"value"for"all"pins"
"
"
"
"
"
**Applying"any"voltage"directly"to"any"of"these"PINs"will"cause"permanent"damage"to"the"GEVCU"
"
"
"
"
"
"
"
"
"
"
"
"
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MICROCONTROLLER
Atmel SAM3X8E ARM Cortex-M3 CPU
32-bit core
CPU Clock at 84Mhz.
96 KB of SRAM.
512 KB of Flash memory for code
256KB EEPROM for persistent data.!
Operating Voltage: 3.3v
Input voltage: 6-16v
CAN network channels: 2
Universal Serial Bus Port: 1
Isolated Analog Inputs: 4
Isolated Digital Inputs: 4
Isolated PWM or Digital Outputs: 8
Programming Environment: Arduino Due IDE 1.5.4
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WIRELESS MODULE
Core CPU: 32-bit RISC ARM7TDMI, !low-leakage, 0.13 micron, at 48MHz
Operating Voltage: +3.3V+/-10%
Operating Humidity: 90% maximum !(non-condensing)
Operating Temperature Range: !-20° to 75°C (-4° to 167°F)
Power Consumption:
Transmit –250mA@16dbm, 235mA@12dbm (typical)
Receive – 190mA (typical)
Power Save mode – 8mA
Power Down mode – 40uA (typical)
RF Connector: SMA reverse polarity
Host Interface: TTL serial interface
Internet Protocols
ARP, ICMP, IP, UDP, TCP, DHCP, DNS, NTP, SMTP, POP3, MIME, HTTP, FTP
and TELNET
Security protocols
SSL3/TLS1, HTTPS, FTPS, RSA, AES-128/256,
3DES, RC-4, SHA-1, MD-5, WEP , WPA and WPA2
Protocols accelerated in hardware: AES, 3DES and SHA
Wireless Specifications:
Standards supported: IEEE 802.11b/g
Frequency: 2.412-2.462GHz
Channels: 11 channels
Host Data Rate: up to 3Mbps in serial mode Serial Data Format (AT+i mode):
Asynchronous character; binary; 8 data bits; no parity; 1 stop bit
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3 Wiring and Connections
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The!GEVCU!must!of!course!be!connected!to!the!car!and!the!inverter/controller!by!wire.!!The!entire!
interface!is!accomplished!through!a!weatherized!AMPSEAL!35]pin!connector!which!is!quite!
conventionally!used!in!automotive!applications.!
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Provided!with!each!GEVCU!unit!from!EVTV!is!a!basic!wiring!harness.!!The!original!genesis!of!GEVCU!
was!the!Arduino!Due!which!featured!a!very!large!number!of!input!and!output!pins.!!!
!
The!AMPSEAL!35!provides!but!a!subset!of!that!but!features!inputs!for!12v!vehicle!power,!two!CAN!
lines!to!the!DMOC645!!AMPSEAL!23]pin!connector,!four!analog!inputs,!four!digital!inputs,!up!to!eight!
digital!outputs!and!!isolated!12v!and!5v!outputs!to!power!sensors.!
!
This!harness!is!a!bit!specialized!for!the!Azure!Dynamics!DMOC645!Digital!Motor!Controller!and!so!
features!an!AMPSEAL!23]pin!connector!for!that!unit.!!This!connector!provides!the!two!CAN!bus!lines,!
an!enable!jumper,!terminating!resistor!for!the!CAN!bus,!12v!vehicle!power!for!the!DMOC645,!and!
breaks!out!an!RS]232!serial!connector!to!the!DMOC645.!!This!can!be!useful!in!the!event!the!firmware!
should!need!to!be!reflashed!or!internal!variables!modified!with!a!program!titled!ccShell.!!ccShell!and!
instructions!for!connecting!to!the!DMOC645!for!this!purpose!can!be!found!at!http://forums.evtv.me.!
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This!cable!would!need!to!be!modified!for!other!controller/inverters!such!as!the!UQM!Powerphase!
100.!
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While!the!GEVCU!has!a!limited!number!of!digital!and!analog!inputs!and!outputs,!they!are!really!quite!
capable!of!handling!a!number!of!necessary!duties!in!controlling!a!vehicle.!!And!the!unit!does!feature!
TWO!CANbus!ports,!one!rather!dedicated!to!the!DMOC645!but!the!other!quite!free!to!interact!with!
the!vehicle.!!In!this!way,!GEVCU!can!be!extended!with!other!CAN!equipped!multicontrollers!used!for!
battery!monitoring,!informational!displays,!charging!issues,!etc.!
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BASIC&THROTTLE&WIRING&
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As!an!example,!we!will!describe!some!basic!throttle!
wiring!for!the!GEVCU!as!this!is!the!minimum!necessary!
application!to!control!a!motor.!
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A!basic!throttle!potentiometer!is!shown!in!the!diagram!.!!
The!potentiometer!is!a!variable!resistor!that!basically!
“divides”!a!voltage!based!on!varying!the!point!along!a!
linear!resistance!where!the!voltage!is!sampled.!!This!
signal!output!is!tied!to!our!1st!analog!input!line!AIN0!at!
pin!20!of!the!AMPSEAL!35.!!The!voltage!to!be!divided!is!
provided!by!tying!one!end!of!the!pot!to!our!+5v!output!

Operation*Manual*GEVCU*Version*5.20********November*2014*
!
14!
available!on!several!pins!for!convenience!–!in!this!case!pin!24.!!The!other!end!of!the!pot!is!tied!to!our!
reference!ground!at!pin!29.!!!
!
In!this!way,!as!you!press!on!the!accelerator,!the!potentiometer!is!varied,!increasing!the!voltage!from!
zero!to!five!volts!at!maximum!pedal.!!In!practice,!this!is!usually!something!like!0.80v!to!4.50!v.!!!
!
Hall!Effect!pedals!work!on!a!different!principle!than!variable!resistors!–!magnetic!inductance.!!But!
from!a!wiring!standpoint!are!no!different.!!They!still!need!a!5v!power!source!and!reference!ground.!!!
And!they!still!provide!a!signal!output!that!we!tie!to!one!of!
our!analog!inputs.!
!
Many!modern!throttles!have!two!pots!or!hall!effect!
modules!and!provide!TWO!signal!outputs.!
!
This!is!to!provide!a!“sanity!check”!to!make!sure!the!
throttle!input!is!valid.!!For!example,!if!the!signal!output!
and!the!5v!lines!were!shorted,!this!might!be!read!as!a!max!
throttle!input!and!the!vehicle!accelerate!uncontrollably.!!!
!
Two!wire!throttles!provide!two!different!outputs!and!they!
usually!are!NOT!identical.!!!For!example,!one!output!might!
vary!from!0.8!to!4.5v!while!the!second!varies!from!1.5v!to!
3.4v.!!The!sanity!check!association!in!comparing!those!two!signals!must!be!handled!in!software.!!
Indeed,!one!signal!might!vary!from!0.8!at!idle!and!4.5v!at!max,!while!the!other!is!inverted,!showing!
3.5v!at!idle!and!1.2v!at!max!pedal.!Again,!this!association!must!be!controlled!by!the!software.!!GEVCU!
software!currently!supports!all!of!these!modes.!!You!will!have!to!select!1!wire!or!2,!and!whether!the!
values!are!linear!or!inverted.!
!
USING&EXISTING&VEHICLE&DRIVE&BY&WIRE&THROTTLES&
!
Many!modern!vehicles!already!feature!an!accelerator!that!is!wired!for!producing!these!signals.!!It!is!
relatively!easy!to!locate!the!signal!lines!and!tap!into!them!for!connection!to!the!GEVCU.!!Generally!it!
is!good!practice!to!use!both!signal!outputs!where!available.!!That!the!pedal!gets!5v!from!the!normal!
ECU!is!not!a!problem!as!5v!is!more!or!less!5v!regardless!of!source.!!But!it!does!have!to!be!referenced!
to!the!same!ground.!!So!generally,!you!want!to!tap!both!accelerator!outputs!AND!connect!the!
associated!return!from!the!pedal!to!one!of!the!GND!input!pins!on!the!GEVCU!AMPSEAL!35.!
!
!
BRAKES&
!
Most!electric!cars!map!both!acceleration!and!regenerative!braking!to!the!throttle,!using!the!first!part!
of!pedal!travel!for!regenerative!braking!and!the!latter!portion!of!pedal!travel!for!forward!
acceleration.!!You!will!rather!quickly!learn!to!not!only!drive!this!way,!but!usually!decelerate!to!a!stop!
using!the!regenerative!braking!and!it!becomes!kind!of!a!single]footed!driving!pattern!that!most!
drivers!find!very!controllable!and!natural.!!!
!

Operation*Manual*GEVCU*Version*5.20********November*2014*
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15!
But!many!want!regenerative!braking!to!assist!slowing!the!car!when!using!the!brake!and!some!do!
NOT!like!the!use!of!regenerative!braking!on!the!throttle!at!all!and!ONLY!want!it!applied!during!actual!
braking.!
!
The!only!way!we!have!found!to!controllably!
vary!the!DEGREE!of!regenerative!braking!
from!the!brake!pedal!is!to!use!a!hydraulic!
pressure!transducer!that!operates!
essentially!just!like!a!throttle!pot.!!These!
transducers!again!require!a!5v!supply!and!
ground!return,!and!again!provide!a!signal!
output!from!0.5!to!4.5v!typically,!increasing!
as!the!pressure!in!the!brake!lines!is!
increased.!!The!transducer!has!to!be!
connected!to!the!existing!hydraulic!brake!
lines.!
!
By!convention,!GEVCU!uses!AIN0!for!1!wire!
throttles,!AIN0!and!AIN1!for!two!wire!
throttles,!and!AIN2!for!brake!inputs.!
!
The!following!diagram!shows!a!more!complete!wiring!view!of!the!GEVCU!as!installed!on!the!EVTV!
VW!THING!build.!

Operation*Manual*GEVCU*Version*5.20********November*2014*
!
16!
!

Operation*Manual*GEVCU*Version*5.20********November*2014*
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17!

Operation*Manual*GEVCU*Version*5.20********November*2014*
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18!
4 USB SERIAL PORT INTERFACE
!
The!key!concept!in!the!GENERALIZED!vehicle!control!unit!is!that!it!is!generalized.!!That!is,!it!can!be!
configured!and!used!in!a!variety!of!different!vehicles!using!different!drive!train!and!vehicle!
components.!
!
The!open!source!nature!of!the!GEVCU!software!allows!anyone!with!basic!C++!coding!skills!to!extend!
this!ad!infinitum.!!However,!for!most!users,!C++!is!a!bridge!too!far.!!You!can!easily!use!GEVCU!by!
changing!a!few!simple!variables!requiring!no!programming!knowledge!whatsoever.!
!
The!design!philosophy!is!to!avoid!specialized!software!programs!that!are!operating!system!
dependent!and!require!updating.!!To!accommodate!future!use!of!GEVCU,!we!cannot!predict!what!
operating!systems!will!be!used!and!we!do!not!want!the!overhead!of!updating!a!specialized!
“configuration!program”!in!any!event.!!For!far!too!much!of!our!EV!equipment,!we!find!outdated!
buggy!software!running!on!obsolete!and!in!some!cases!hardly!available!operating!systems!in!order!
to!change!a!few!simple!variables.!
!
But!everyone!that!touches!GEVCU!wants!something!more!and!having!it!be!powerful!and!extensible!is!
certainly!desirable.!!We!see!three!basic!interfaces!for!non]programmer!users.!
!
1. USB!Serial!Port!terminal!program!
2. Any!web!browser!via!802.11b/g!WiFi!wireless.!
3. Mobile!tablet!or!phone!interface!via!CANbus/OBDII!connector.!
!
In!this!way,!we!can!avoid!depending!on!specific!operating!systems!or!programs!beyond!a!basic!serial!
terminal!program!or!web!browser!running!on!ANY!device.!!And!at!the!same!time!provide!for!
gorgeous!graphic!interfaces!to!actually!serve!as!a!Tesla!style!interface!for!our!vehicles.!
!
The!most!basic!albeit!primitive!of!these!three!is!the!USB!serial!port!terminal!program.!!GEVCU!
features!a!printer!style!USB!port!on!the!rear!panel!simply!because!these!appear!to!be!the!most!
physically!durable!and!robust!connectors!for!USB.!!!
!
On!powerup,!GEVCU!will!interface!via!USB!serial!port!using!simple!ASCII!characters!and!line!feeds.!
You!can!interact!usefully!with!GEVCU!via!any!serial!terminal!program!on!any!laptop!or!other!
computer!device.!!This!USB!bootstrap!operation!is!a!central!tenet!of!the!Arduino!concept.!
!
Serial!communications!dates!back!to!the!early!modems!and!electronic!bulletin!boards!and!has!its!
own!quirks!and!foibles.!!!It!is!so!dated!that!neither!Microsoft!nor!Apple!actually!include!a!serial!
terminal!program!with!their!operating!system.!!But!because!the!need!for!basic!serial!
communications!never!quite!goes!away,!terminal!programs!for!both!are!still!readily!and!in!most!
cases!freely!available.!
!
!
!
!

Operation*Manual*GEVCU*Version*5.20********November*2014*
!
19!
There!are!some!basic!terminal!settings!that!must!be!set!on!most!terminal!programs!in!order!to!“talk”!
to!the!GEVCU.!
!
Data Rate: 115,200 bps
Data bits: 8
Parity bits: None
Stop bits: 1
Character set: ASCII.
!
And!so!to!configure!GEVCU!at!its!most!basic!level,!you!must!first!configure!an!ASCII!serial!data!
terminal!program.!!Many!of!these!offer!many!features!allowing!you!to!set!screen!color,!font!,!!text!
size,!color.!!Etc.!!They!can!also!allow!you!to!“capture”!text!sent!over!the!port.!
!
GEVCU!was!born!of!the!Arduino!Due!educational!platform!and!many!actually!develop!C++!code!via!
the!Arduino!Integrated!Design!Environment!or!IDE.!!This!IDE!actually!includes!a!terminal!program.!
!
If!all!else!fails,!Arduino!is!freely!available!for!download!and!installation!on!Windows,!Mac!OS!X,!or!
Linux!fully!featured!and!entirely!free!of!charge.!!So!it!may!be!the!easiest!way!to!get!and!install!a!
terminal!program!for!many!users.!
!
GEVCU!is!currently!usable!with!Arduino!Version!1.5.4.!!There!are!some!problems!with!some!of!later!
versions!of!the!Arduino!IDE.!!Until!those!are!resolved,!we!would!urge!you!to!use!1.5.4.!
!
After!downloading!and!installing!Arduino.!!At!the!top!of!screen!you!will!find!menus.!!Select!TOOLS,!
and!in!the!submenu!
PORT.!!Then!select!the!
hardware!USB!port!you!
have!connected!to!
GEVCU.!
!
For!Mac!OSX!or!Linux,!
the!available!USB!ports!
will!appear!as!CU!or!TTY!
entries.!
!
For!Windows,!more!
likely!something!like!
COM1!or!COM2.!
!
!
!
!
!
!
!
!
!
!
!

Operation*Manual*GEVCU*Version*5.20********November*2014*
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20!
Once!the!port!is!selected,!use!the!same!TOOLS!menu!to!select!
BOARD!for!the!ARDUINO DUE NATIVE USB!port.!!GEVCU!
actually!does!not!have!a!PROGRAMMING!port!but!uses!the!native!
USB!port!of!the!multicontroller!chip!for!both!tasks.!
!
Once!the!port!and!board!are!selected,!you!can!use!the!SERIAL
MONITOR!entry!on!the!TOOLS!menu!to!bring!up!a!separate!
serial!terminal!window.!
!
This!window!will!feature!a!data!entry!field!at!the!top!of!the!
screen!and!a!larger!display!area!for!text!received!from!the!
GEVCU.!!
!
The!only!thing!
you!will!see!
initially!is!most!
likely!a!period!that!appears!on!screen.!!Every!few!
seconds,!you!will!see!another!one!!This!is!the!
GEVCU!heartbeat.!
!
If!you!enter!a!question!mark!(or!lower!case!h)!on!
the!data!entry!field!and!press!enter!or!return!key!
you!should!see!a!full!GEVCU!menu!in!all!its!gory!
and!hideous!glory.!!!
!
If!you!actually!get!garbage!or!garbled!text,!make!
sure!the!data!rate!in!the!lower!right!hand!corner!
of!the!terminal!program!is!set!for!115,200.!
!
This!screen!allows!you!to!configure!and!use!
essentially!all!the!features!of!the!GEVCU!by!
entering!commands!in!the!data!field!area.!
!
Note!that!not!all!menu!features!will!appear!until!
the!associated!module!is!enabled!as!described!in!
Section!5.!
!
The!Browser/Wireless!configuration!interface!
and!the!CANbus!OBDII!configuration!interface!
will!be!further!described!later!in!this!manual.!
!
!
!
!
!
!
!