Cortex VEXnet User manual

Cortex Microcontroller and VEXnet Joystick User Guide
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1. Cortex Microcontroller and VEXnet Joystick Pairing Procedure:
a. The Joystick must rst be paired to the Cortex Microcontroller before they will work using the VEXnet Keys. Pairing
requires a USB A-A Cable and a VEX 7.2V Battery. This process must be completed each time you use a Joystick
or Cortex with a new mate. A Joystick can only communicate with a Cortex that it has been paired with. During the
Pairing Process, the ID from the Cortex is transferred to the Joystick; thus mating the two units together.
0114
b. Start with the Cortex and Joystick turned OFF.
c. Connect the Cortex to the Joystick using a USB A-A Cable.
d. Connect the 7.2V Robot Battery to the Cortex.
e. Power up only the Cortex.
f. A successful tether is indicated by a Solid Green VEXnet LED on both the Joystick and the Cortex (See Figure Below).
– The Solid Green VEXnet LED must remain ON both units at the same time for a minimum of 5 seconds.
– Disregard the other LEDs as you are only interested in the VEXnet LED.
– Pairing may take up to one minute to complete.
g. Once the units have nished pairing, turn OFF the Cortex.
h. Disconnect the USB A-A Cable from both units.
i. Disconnect the 7.2V Robot Battery from the Cortex.

Cortex Microcontroller and VEXnet Joystick User Guide
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2. Basic connections; batteries, microcontroller, Joysticks and (2) VEXnet keys.
a. Attach a 7.2v battery and a VEXnet USB Key to the Cortex as shown.
b. Install six identical batteries as shown. Use Alkaline, Ni-Cad or Ni-MH type batteries, but DO NOT mix different
kinds of batteries. Charge rechargeable batteries only with a quality charger designed for your battery type.
c. Reinstall the battery cover (insert the two tabs of the battery cover rst along the back edge of the battery cover to aid
in installation) and then tighten the cover screw. Then add the VEXnet USB Key as shown.

Cortex Microcontroller and VEXnet Joystick User Guide
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d. You can also power your Joystick directly from a standard wall outlet using the Joystick Power Adapter (276-1710).
Simply plug this cable into your Joystick’s PROGRAM/FACTORY port and you can operate your Joystick without the
use of batteries. Please note: when using the Joystick Power Adapter, it is not necessary to turn your Joystick ON.
Also, the JOYSTICK/POWER LED can be ignored.
e. Turn on the Cortex and Joystick by setting the power switches to ON as shown in the two pictures below.

Cortex Microcontroller and VEXnet Joystick User Guide
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f. A valid link is shown below. The VEXnet LED will be blinking fast green on both the Cortex and Joystick. The VEXnet
light is the only LED that determines a valid link. It usually takes 5 to 10 seconds to successfully establish a link. Once
the units are linked, the Robot and Joystick LED Indicators will show the battery levels in their respective unit. A
green Robot or Joystick LED indicates that their respective batteries are fully charged batteries. As the battery levels
decrease, these LEDs will change to yellow and then red.
g. If the units fail to establish the VEXnet link after 30 seconds, turn them both OFF and then back ON. If they still fail
to link up, refer to the Troubleshooting Flowchart in section 7.
 3. BasicConguration
A few examples of the Default Code that is preloaded onto the Cortex Microcontroller are shown below. For complete
details on the Default Code, refer to Section 4. Please note: The default code for the Cortex Microcontroller varies
from that of the PIC Microcontroller. Please review and follow the tables in this document to ensure your robot
behaves in the manner you wish.
a. Add motors and test. The following picture shows two VEX 3-Wire Motors plugged into Motor Port 2 and Motor
Port 5. With the Default Code, pushing Joystick Channel 3 up will cause Motor 2 to turn clockwise. Pushing Joystick
Channel 2 up will cause Motor 5 to turn counterclockwise.
b. Motor Reversing: The Default Code allows jumpers or switches to be installed in the Digital Ports to invert the motor
direction. This is useful to correct the direction of motors without changing code, or when using a switch to reverse a
motor if the robot hits an object. The following picture shows motor reversing jumpers installed in Digital Ports 2 and
5 to reverse Motor Ports 2 and 5. If you are using 2-wire motors, another way to invert the motor’s direction is to
reverse the motor’s connection where it is plugged into a Motor Controller 29 Module or Motor Ports 1 or 10 on the
Cortex.

Cortex Microcontroller and VEXnet Joystick User Guide
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c. Two Joystick Operation: If desired, a second Joystick can be added to allow two drivers to operate a single robot.
Simply connect a second VEXnet Joystick or a Partner Joystick to your main VEXnet Joystick using a coiled handset
cable plugged into the Joysticks’ PARTNER Ports. Only the main Joystick should have a VEXnet Key installed.
When using the Default Code, you will need to install a jumper into Digital Port 11 in order to activate two-Joystick
operation.
d. Limit Switch Inputs: The Default Code allows jumpers or switches to be installed in the Analog Ports to limit certain
motor directions. These are useful for stopping a motor when an arm bottoms out. A limit switch plugged in to
Analog 1 will stop Motor 6 from turning counterclockwise when activated. A limit switch plugged in to Analog 2 will
stop Motor 6 from turning clockwise when activated.

Cortex Microcontroller and VEXnet Joystick User Guide
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 4. DefaultOperation:RefertotheattachedguresfordetailsandoptionsofJoystickinputtoMotorresponse.
These motor directions will make a Protobot robot go forward when the joysticks are pushed up. Note the Jumper
variations for each section.
Please note: The default code for the Cortex microcontroller varies from that of the PIC microcontroller. Please
review and follow the tables in this document to ensure your robot behaves in the manner you wish.

Cortex Microcontroller and VEXnet Joystick User Guide
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a. The Cortex may be reprogrammed with user-created code. The hardware setup for wireless downloading is shown
below. For non-wireless downloading, the VEXnet keys may be substituted with a USB A-A cable. You can also
download code directly to the Cortex using the USB A-A cable.
Arcade Mode - Channel 1 (right stick, X-axis) + Channel 2 (right stick, Y-axis)
Arcade Mode - Channel 1 (right stick, X-axis) + Channel 2 (right stick, Y-axis)
Arcade Mode - Channel 1 (right stick, X-axis) + Channel 2 (right stick, Y-axis)
Channel 1 (right stick, X-axis)
Motor 1
LEFT DRIVE
Joystick Right = Motor CW
Robot Turn Rate
Motor 2
LEFT DRIVE
Joystick Right = Motor CW
Motor 3
LEFT DRIVE
Joystick Right = Motor CW
Motor 4
RIGHT DRIVE
Joystick Right = Motor CW
Motor 5
RIGHT DRIVE
Joystick Right = Motor CW
Motor 10
RIGHT DRIVE
Joystick Right = Motor CW
Channel 2 (right stick, Y-axis)
Motor 1
LEFT DRIVE
Joystick Up = Motor CW
Robot Forward Speed
Motor 2
LEFT DRIVE
Joystick Up = Motor CW
Motor 3
LEFT DRIVE
Joystick Up = Motor CW
Motor 4
RIGHT DRIVE
Joystick Up = Motor CCW
Motor 5
RIGHT DRIVE
Joystick Up = Motor CCW
Motor 10
RIGHT DRIVE
Joystick Up = Motor CCW
Reverse Motor Direction
Reverse Motor 1
Jumper in Digital 1
Reverse Motor 2
Jumper in Digital 2
Reverse Motor 3
Jumper in Digital 3
Reverse Motor 4
Jumper in Digital 4
Reverse Motor 5
Jumper in Digital 5
Reverse Motor 6
Jumper in Digital 6
Reverse Motor 7
Jumper in Digital 7
Reverse Motor 8
Jumper in Digital 8
Reverse Motor 9
Jumper in Digital 9
Reverse Motor 10
Jumper in Digital 10
Limit Switch Inputs
Motor 6 ignores CCW
Jumper in Analog 1
Motor 6 ignores CW
Jumper in Analog 2
Motor 7 ignores CCW
Jumper in Analog 3
Motor 7 ignores CW
Jumper in Analog 4
Motor 8 ignores CCW
Jumper in Analog 5
Motor 8 ignores CW
Jumper in Analog 6
Motor 9 ignores CCW
Jumper in Analog 7
Motor 9 ignores CW
Jumper in Analog 8
276-2186
Programming Cable
Program
Port
Cortex
Microcontroller
Cortex
Microcontroller
VEXnet
Joystick
PC PC
USB Port USB Port

Cortex Microcontroller and VEXnet Joystick User Guide
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5. Diagnostics Information: refer to the following chart for Joystick and Cortex LED patterns and meanings.
Robot, VEXnet, and Game LED’s
show the same data [2]
Joystick [5] Robot VEXnet Game
Medium (yellow) Initialize - Looking for PC or Tether Mate
Blip (yellow) Startup - Looking for USB Key
Fast (yellow) Linking - Searching for VEXnet Mate
Fast (green) Linked
Slow (green / yellow) Linked - Data quality reduced
Slow (green / red) Linked - Poor Data quality reduced
Solid (green) Tethered to Mate or PC
Slow (red) single blink Fault: Lost Link - Searching for VEXnet Mate
Slow (green) Downloading User Code [1]
Note 1: Does not apply to ROBOTC User Code Downloads
Joystick [5]
Robot [1] VEXnet Game
(red)
Main Battery = Dead (<5.5v) or CORTEX Off [2]
(yellow)
Main Battery = Low (<6.5v) [2]
(green)
Main Battery = Good
Solid All Good: Both Joysticks connected
Solid + 1 Blink
All Good: Tx1 Joystick connected
Fast Autonomous only mode
Fast (red) [3] Fault: Low Backup Battery (0v-8v)
Slow (red) Fault: User Microprocessor Issue
Note 1: Robot LED only work when Linked
Note 2: Lowest CORTEX battery color latched at Joystick and CORTEX
Note 3: No Backup Battery only indicated if competition cable is connected.
Joystick [5] Robot VEXnet Game
Off No Competition connection
Solid (green) Driver [4]
Fast (green) Autonomous
Fast (yellow) Disabled
Note 4 : Game LED Driver Indicator is only used when the competition cable is connected.
Joystick [5] Robot VEXnet Game
(red)
Joystick Battery = Dead (<5.5v)
(yellow)
Joystick Battery = Low (<6.5v)
(green)
Joystick Battery = Good
Fast Two Joysticks in use
Solid One Joystick in use
Note 5 : Joystick LED only on Joystick.
Update Utility Tool Indicators
Joystick [5] Robot VEXnet Game
Solid (green) Tether to PC
Slow (green) Flickering (green) Bootload Mode - Ready to update firmware
Slow (green) Slow (red) Flickering (green) Downloading Master Code
Other Indicators
Joystick [5] Robot VEXnet Game
(red) (red) (red) (red) Flash on all 3 indicates a Reset
Slow (red) double blink NO VEXnet Key detected
Slow (red) double blink Invaild ID in the CORTEX
Slow (red) double blink Invaild ID in the Joystick

Cortex Microcontroller and VEXnet Joystick User Guide
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6. VEXnet Joystick Calibration Procedure:
a. The Joystick must be linked to the Cortex Microcontroller using the VEXnet Keys.
b. Hold the “6U” Back Switch depressed.
c. While the “6U” Back Switch is depressed, use a small Allen Wrench (1/16” or smaller) or similar small straight tool
to depress and hold the CONFIG Switch.
d. Hold both Switches depressed until you see the Joystick LED Flash red and green – you can now release both
Switches.
– There is a 10 second time limit to complete the following steps 5 and 6.
e. Move both Analog Joysticks to the maximum position desired in all 4 directions – Up, Back, Left, and Right.
–. If a movement is not detected in all 4 directions, a timeout will occur after about 10 seconds and the
Calibration Mode will be discontinued and the VEXnet LED will briey ash red.
–. The Joystick LED will continue to ash red and green during the calibration process.
f. After movement is detected in all 4 directions, the Joystick LED will be ON and solid green.
– To save the calibration, depress and release the “8U” top button.
– If the calibration is accepted and saved, the Joystick LED will start ashing fast green for a few seconds.
– If the calibration is not saved, a timeout will occur after about 10 seconds and the Calibration Mode will be
discontinued and the VEXnet LED will briey ash red.
– To cancel the calibration, depress and release the “7U” top button. The Calibration Mode will be discontinued
and the VEXnet LED will briey ash red.
– If the Calibration Mode is discontinued or saved, the Joystick LEDs will resume their normal function after the
VEXnet LED briey ashes.
g. If Joystick Master Firmware is downloaded into the Joystick, the Joystick will need to be recalibrated.
Cong Switch
7U8U
6U

Cortex Microcontroller and VEXnet Joystick User Guide
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Is the
Game LED
flashing?
Do all
LEDs
flash Red in a
repeating
cycle?
Is
Cortex
VEXnet LED
on?
Is the
Robot LED
blinking?
Fast
or slow
blink?
Is the
VEXnet LED
green?
Does
the Cortex
turn on?
Start
Single
or double
blink?
Do all
motors work
correctly?
Are you
having trouble
running your
competition
autonomous
code?
Is the
Robot LED on
the Cortex
consistently
red?
7. General Robot Troubleshooting Flowchart
Check batteries and power connections. The battery connectors on
the Cortex can become bent open over time. If necessary, bend the
connectors back in to ensure a solid power connection.
Low or missing 9v backup battery.
If in a competition setting, install a
fully charged 9v backup battery before
continuing
Programming error. Try switching to
the Default Code which can be found
within your programming software. If
this xes the issue, return to your user
code and attempt to isolate the issue to
a particular line of code. The best way
to do this is to comment out various
sections at a time and test after each
change.
If the units are still not correctly linked, refer to the
VEXnet Troubleshooting Flowchart in Section 8.
Robot battery is dead.
Charge or replace batteries
before continuing.
Fast
Single
Double
Slow
YES
YES
NO
NO
NO
NO
NO
NO
NO
NO
NO
YES
YES
YES
YES
YES
YES
YES
Update the VEXnet Firmware (Master CPU Firmware
for ROBOTC users) on both the Cortex and the Joystick
using the Firmware Upgrade Utility included with your
programming software. If you do not have programming
software this utility is available on the Downloads page
at vexrobotics.com.
The Cortex is currently running an Autonomous Only
user code. If you want to use the VEXnet Joystick,
download a VEXnet Enabled project such as the Default
Code using the USB A-A Cable.
When programming a competition robot, it’s very
important that you write your code in a competition
template so that the Field Controller will be able to
correctly enable/disable your robot. Note: during
autonomous the VEXnet Joystick is disabled.
For any other issues, you can refer to the other guides or post a question on the
VEX Forum (vexforum.com). You can also contact VEX Technical Support by
phone at [phone] or email [email protected]. Please note:
for programming questions contact the developer of your programming software.
Wait 20 second…
Refer to the Motor Troubleshooting Flowchart in Section 9.