1. Vex Cortex Controller System and Programming

2. Who are we? Naomi Fitzsimmons Matt Lapolla John Robertson Bill Ryan
Parts replacement
Matt Lapolla
Programming, Technical issues, Rules, etc.
John Robertson
Policies, Technical Issues, Scoring
Bill Ryan
Everything else

3. Overview Terminology Hardware Overview Programming Languages
Programming example
Defining Inputs
Defining Outputs
Input - Output Relationship
Write Program
Test Program
Other Useful Functions
Appendix

4. Terminology

5. Terminology: Proportional or Non-Proportional
Dimmer Light Switch
Regular Light Switch
Proportional
(Analog)
Non-Proportional
(Digital)

6. Terminology: Motor with Limit
Transmitter
Cortex

7. QUESTIONS? Servo vs Motor Robot Transmitter Cortex Controller -32 -127
-64
127 32 64
QUESTIONS?
Cortex Controller
Motor
Servo

8. Terminology: Programming software
Compile – changes your C program into object code that the linker understands.
Link – combines your program’s object code with the Intelitek library and other libraries to create code that is executable on the Cortex processor.
Download / Bootload – transfers the machine code version of your program from the PC to the Cortex where it will execute (the IFI/Intelitek Loader will perform the transfer via the PC USB cable)

9. HARDWARE OVERVIEW

10. Return Kit Controller Servos Joystick Analog motors/ servos battery
Digital
i/o
WiFi key
USB/Tether
Serial
AAA Battery
Charger
Picture Not
Available
Servo Extensions
(2)
Servo Power Adaptor
(2)
Servo Horns
(4)
USB A-A cable
(2)
Servo Mount H/W
(16)
(2)

11. Return Kit Drive components Motors 7.2V Battery charger Motor
(2)
Motors
7.2V Battery charger
Picture Not
Available
(2)
Motor
controller (4)
Battery adapter
Screw terminal
sensor i/f cable (8)
(2)
7.2V Battery
(2)
Screw terminal
motor i/f cable (4)

12. Example Hookup

13. Hardware Overview: Joystick
8 buttons on top
2 XY analog joysticks
6 AAA
rechargeable
batteries
Power switch
Plug-in USB/ WiFi Key
4 Button on front-side
Partner/ Buddy Control Support
3 Axis Accelerometer
(XY Tilt, XYZ Accel, Shake)

14. Hardware Overview: Joystick – What you will use
8 buttons on top
2 XY analog joysticks
6 AAA
rechargeable
batteries
Power switch
Plug-in USB/ WiFi Key
4 Button on front-side
Partner/ Buddy Control Support
3 Axis Accelerometer
(XY Tilt)
3 Axis Accelerometer
(XY Tilt, XYZ Accel, Shake)

15. Hardware Overview: Cortex Controller
USB
Standard Serial
Interfaces
(UART, I2C) 1
Analog in 8 1 1
2-wire motor
Digital
in/out 2
3-wire PWM
servo/motor ctrl 12 9
Speaker
Out SP 10
2-wire motor

16. Hardware Overview: Cortex Controller – What you will use
USB
Standard Serial
Interfaces
(UART, I2C) 1
Analog in 8 1 1
2-wire motor
Digital
in/out
Digital in 2
3-wire PWM
servo/motor ctrl 12 9
Speaker
Out SP 10
2-wire motor

17. Hardware Overview: Cortex Controller
This will only be important on Game Day.
Install before each match.
Remove after each match.
configuration switch (used for special procedures)
75MHz crystal interface ports
On/Off switch
backup battery port for WiFi communications (9V)
main battery port (7.2V)

18. Hardware Overview: Cortex Controller – What you will use
configuration switch (used for special procedures)
75MHz crystal interface ports
On/Off switch
backup battery port for WiFi communications (9V)
main battery port (7.2V)

19. Hardware Overview: Cortex Controller
Ground
+ 5V
Signal/Control
+ Battery Power
+ Motor Power
(for + control input)
- Motor Power
(for – control input)

20. Hardware Overview: DC Motors
Do not solder to motors. Use spade connectors instead.
Polarity is NOT marked on motors: positive(+), negative(-)
Wiring and programming will determine clockwise or counter clockwise rotation for positive stick movement
Mount motors with VEX Motor Mounting Kit

21. Hardware Overview: DC Motors
For power reasons, spread your motors so that you have
no more than 2 motors plugged into ports 2-5 and
no more than 2 motors plugged into ports 6-9.
You risk overcurrent and shutdown of the processor.
Servo/motor ports are divided into 2 banks
Bank1 = Ports 1-5
Bank2 = Ports 6-10
Each bank can support a maximum of 4 Amps of current
BEST large motor stall current can reach 3.5 Amps.
Sheet metal shield around the large motors IS needed and should not be removed.

22. Hardware Overview: DC Motors
If using built-in motor controller(s)
connect via 2-wire screw terminal cables (red/black)
use motor ports 1 & 10 only
If using external motor controller(s)
connect via 3-wire external motor controller + 2-wire screw terminal cable
use motor ports 2 thru 9 only

23. Hardware Overview: 2 wire Motor connection Ports 1, 10
Screw terminals
for attaching
motor wires
Connector is not keyed.
Allows swapping polarity.
Port 1
and
Port 10
Built-In Motor
Controllers

24. Hardware Overview: 3 wire Motor connection Ports 2 - 9
Suggest using
a 4” wire tie or
heat shrink tubing here
External Motor
Controller
Standard 2-wire
motor cable
Standard 3-wire
PWM connector
Plug in to
Motor Ports 2 thru 9
Screw terminals
for attaching
motor leads

25. Hardware Overview: Servo – Electrical Connection
White to White
Black to Black
Futaba S3003 or S3004 series
Maximum 120 degree rotation (+60, -60)
Connection to Cortex controller
use motor ports 2 thru 9 only
Servo horns may be modified
2x3 pin header
Servo Power Adapter Cable
via 3-wire PWM + 2x3 pin header
servo horns
(2)
(2)
(1)

26. Hardware Overview: Servo – Electrical Connection
Insert a 2x3 pin header
Occupies 2 ports
Converts VEX female port to male port
Because Futaba servos have female connectors

27. Hardware Overview: Servo – Electrical Connection
Insert a Servo Power Adaptor
Converts VEX female port to male port and provides protection
Because Futaba servos have female connectors

28. Hardware Overview: Servo – Electrical Connection
Servo connectors are keyed for proper insertion.
(small tab shown)
Servo Cables
White= Data
Red = +Batt Voltage
Black = Gnd
Second half of 2x3
pin header.

29. Hardware Overview: Servo – Mounting Hardware
Futaba 3003/3004 Servos
4 per Kit
Mounting Hardware for each
To eliminate damage to mounting holes
Servo Mounting Hardware
Rubber grommet (2)
Brass spacer (4)
Mounting screw (4)
Note: There are 16 of each screw, spacer, grommet in the Return Kit.

30. Hardware Overview: Servo – Mounting Hardware
1. No h/w attached
2. Attach rubber grommets
3. Insert brass spacers
4. Secure servo with screws

31. Hardware Overview: Digital Input/Output
Use for switches
Connect to Cortex digital inputs using 2-wire sensor screw terminal cables (white/black wires)
sensor screw terminal cable
Connect to switch
Connect to Cortex
digital input port

32. Hardware Overview: Digital Input / Output
must program digital port for proper direction (input)
Open: Program reads as ‘1’ ; Closed: Program Reads as ‘0’
sensor cable
connector is keyed
use digital ports
1 thru 12

33. Programming Languages

34. Programming Languages
Three different programming environments available
MathWorks Simulink
easyCv4
RobotC

35. Programming Languages: Simulink
Simulink is graphical programming/modeling environment
Simulation capability (see what your program will do before you download it to the Cortex)

36. Programming Languages: Robot C
RobotC programs in C with a text editor, but it has runtime debugging (can step through program line by line and see what the results are)

37. Programming Languages: Easy C
easyC is a block programming environment (similar to software for Lego Mindstorms)

38. Programming Example

39. Programming Example: Steps to creating a program
Open new Easy C workspace
Define Inputs
Define Outputs
Define Input to Output relationship
Write a program
Compile Program
Download
Test Program

40. Programming Example: Open Easy C

41. Programming Example: Open New Project

42. Programming Example: Open New Project

43. Programming Example: Save your New Program

44. Programming Example
Defining Inputs

45. Defining Inputs: Joystick, Switches and Digital Signals
What are the Inputs?
Joystick Input Options
Proportional
Channel 1
Channel 2
Channel 3
Channel 4
Tilt X
Tilt Y
Digital Inputs
Channel 5 Up, Down
Channel 6 Up, Down
Channel 7 U, D, R, L Channel 8 U, D, R, L
Controller Input Options
Digital 1
Digital 2
Digital 3
Digital 4
Digital 5
Digital 6
Digital 7
Digital 8
Digital 9
Digital 10
Digital 11
Digital 12

46. Defining Inputs: Joystick, Switches and Digital Signals
Channel 1
Drive: Turn Right Left
Channel 2
Drive: Forward/Reverse
Joystick Input Options
Proportional
Channel 1
Channel 2
Channel 3
Channel 4
Tilt X
Tilt Y
Digital Inputs
Channel 5 Up, Down
Channel 6 Up, Down
Channel 7 U, D, R, L Channel 8 U, D, R, L
Controller Input Options
Digital 1
Digital 2
Digital 3
Digital 4
Digital 5
Digital 6
Digital 7
Digital 8
Digital 9
Digital 10
Digital 11
Digital 12

47. Defining Inputs: Joystick, Switches and Digital Signals
Channel 1
Drive: Turn Right Left
Channel 2
Drive: Forward/Reverse
Channel 3
Arm: Raise and Lower
Joystick Input Options
Proportional
Channel 1
Channel 2
Channel 3
Channel 4
Tilt X
Tilt Y
Digital Inputs
Channel 5 Up, Down
Channel 6 Up, Down
Channel 7 U, D, R, L Channel 8 U, D, R, L
Controller Input Options
Digital 1
Digital 2
Digital 3
Digital 4
Digital 5
Digital 6
Digital 7
Digital 8
Digital 9
Digital 10
Digital 11
Digital 12

48. Defining Inputs: Joystick, Switches and Digital Signals
Channel 1
Drive: Turn Right Left
Channel 2
Drive: Forward/Reverse
Channel 3
Arm: Raise and Lower
Digital 1
Arm: Upper Limit
Digital 2
Arm: Lower Limit
Joystick Input Options
Proportional
Channel 1
Channel 2
Channel 3
Channel 4
Tilt X
Tilt Y
Digital Inputs
Channel 5 Up, Down
Channel 6 Up, Down
Channel 7 U, D, R, L Channel 8 U, D, R, L
Controller Input Options
Digital 1
Digital 2
Digital 3
Digital 4
Digital 5
Digital 6
Digital 7
Digital 8
Digital 9
Digital 10
Digital 11
Digital 12

49. Defining Inputs: Joystick, Switches and Digital Signals
Channel 1
Drive: Turn Right Left
Channel 2
Drive: Forward/Reverse
Channel 3
Arm: Raise and Lower
Digital 1
Arm: Upper Limit
Digital 2
Arm: Lower Limit
Channel 5 Up
Wrist: Rotate Up
Channel 5 Down
Wrist: Rotate Down
Joystick Input Options
Proportional
Channel 1
Channel 2
Channel 3
Channel 4
Tilt X
Tilt Y
Digital Inputs
Channel 5 Up, Down
Channel 6 Up, Down
Channel 7 U, D, R, L Channel 8 U, D, R, L
Controller Input Options
Digital 1
Digital 2
Digital 3
Digital 4
Digital 5
Digital 6
Digital 7
Digital 8
Digital 9
Digital 10
Digital 11
Digital 12

50. Programming Example
Defining Outputs

51. Defining Outputs: Motors and Servos
Motor / Servo Output Options
Proportional
Channel 1*
Channel 2#
Channel 3#
Channel 4#
Channel 5#
Channel 6#
Channel 7#
Channel 8#
Channel 9#
Channel 10*
* Can drive motor Direct, No servo control
# Can drive servo Direct, Motor with speed controller

52. Defining Outputs: Motors and Servos
Motor / Servo Output Options
Proportional
Channel 1*
Channel 2#
Channel 3#
Channel 4#
Channel 5#
Channel 6#
Channel 7#
Channel 8#
Channel 9#
Channel 10*
* Can drive motor Direct, No servo control
# Can drive servo Direct, Motor with speed controller

53. Defining Outputs: Motors and Servos
What are the outputs?
Motor / Servo Output Options
Proportional
Channel 1*
Channel 2#
Channel 3#
Channel 4#
Channel 5#
Channel 6#
Channel 7#
Channel 8#
Channel 9#
Channel 10*
* Can drive motor Direct, No servo control
# Can drive servo Direct, Motor with speed controller

54. Defining Outputs: Motors and Servos
Channel 2 (Motor Large)
Right Drive Motor
Channel 9 (Motor Large)
Left Drive motor
Motor / Servo Output Options
Proportional
Channel 1*
Channel 2#
Channel 3#
Channel 4#
Channel 5#
Channel 6#
Channel 7#
Channel 8#
Channel 9#
Channel 10*
* Can drive motor Direct, No servo control
# Can drive servo Direct, Motor with speed controller

55. Defining Outputs: Motors and Servos
Channel 2 (Motor Large)
Right Drive Motor
Channel 9 (Motor Large)
Left Drive motor
Channel 3 (Motor Small)
Raise and Lower Arm
Motor / Servo Output Options
Proportional
Channel 1*
Channel 2#
Channel 3#
Channel 4#
Channel 5#
Channel 6#
Channel 7#
Channel 8#
Channel 9#
Channel 10*
* Can drive motor Direct, No servo control
# Can drive servo Direct, Motor with speed controller

56. Defining Outputs: Motors and Servos
Channel 2 (Motor Large)
Right Drive Motor
Channel 9 (Motor Large)
Left Drive motor
Channel 3 (Motor Small)
Raise and Lower Arm
Channel 8 (Servo)
Wrist: Rotate Up/Down
Motor / Servo Output Options
Proportional
Channel 1*
Channel 2#
Channel 3#
Channel 4#
Channel 5#
Channel 6#
Channel 7#
Channel 8#
Channel 9#
Channel 10*
* Can drive motor Direct, No servo control
# Can drive servo Direct, Motor with speed controller

57. Input – Output Relationship
Programming Example
Input – Output Relationship

58. Input – Output Relationship: Flow Chart, Pseudo-code
Inputs
Program
Outputs
Channel 1
Arcade
Mixing
Motor 2 (Right)
Channel 2
Motor 9 (Left)
Channel 3
Channel 3
If not at limit
Digital 1
Motor 3 (Arm)
Digital 2
Channel 5 Up
Up = Rotate Up
Down = Rotate Down
Servo 8 (Wrist)
Channel 5 Down

59. Programming Example
Write Program

60. Write Program: Set Up Input / Output
The Controller Configuration window is used to identify what the various interfaces will be used for and whether the digital interfaces are configured as inputs or outputs. The Controller Configuration window can be accessed via the Project menu. The example shown is the BEST default program.

61. Write Program: COMMENT..COMMENT!!!!
Drag

62. Write Program: COMMENT..COMMENT!!!!

63. Write Program: COMMENT..COMMENT!!!!

64. Write Program: Endless Loop
1 = Always
Drag

65. Write Program: Endless Loop
Most of your program will be inside the endless loop

66. Write Program: Drive Motors
Inputs
Program
Outputs
Channel 1
Arcade
Mixing
Motor 2 (Right)
Channel 2
Motor 9 (Left)

67. Write Program: Drive Motors
Drag

68. Write Program: Drive Motors

69. Write Program: Drive Motors
Drag

70. Write Program: Drive Motors
Always Joystick #1
Set Left Motor to Motor/Servo Port 9
Set Right Motor to Motor/Servo Port 2

71. Write Program: Drive Motors

72. Write Program: Arm Raise/Lower
Inputs
Program
Outputs
Channel 1
Arcade
Mixing
Motor 2 (Right)
Channel 2
Motor 9 (Left)
Channel 3
Channel 3
If not at limit
Digital 1
Motor 3 (Arm)
Digital 2

73. Write Program: Arm Raise/Lower
Drag

74. Write Program: Arm Raise/Lower
Drag

75. Write Program: Arm Raise/Lower
Channel 3
Always Joystick #1
Motor/Servo 3
Limit Switch Input 1
Limit Switch Input 2

76. Write Program: Arm Raise/Lower

77. Write Program: Wrist Rotate
Inputs
Program
Outputs
Channel 1
Arcade
Mixing
Motor 2 (Right)
Channel 2
Motor 9 (Left)
Channel 3
Channel 3
If not at limit
Digital 1
Motor 3 (Arm)
Digital 2
Channel 5 Up
Up = Rotate Up
Down = Rotate Down
Servo 8 (Wrist)
Channel 5 Down

78. Write Program: Wrist Rotate

79. Write Program: Wrist Rotate
Joystick Channel 5
Set Servo Value
Select Down Button
Select Up Button
Set Servo Value
Servo Port 8

80. Programming Example
Compile and Download

81. Compile and Download: Build and Download

82. Compile and Download: Verify Compile with No Errors

83. Compile and Download: Download Program to Cortex
When you see the following message connect your Cortex Controller to the PC using the supplied USB A-A cable.
Then click on the YES button.

84. Compile and Download: Download Program to Cortex
Hopefully you will see this.
Then click on the OK button.

85. Programming Example
Test Program

86. Test Program Ensure your robot is ‘safe’ to operate:
Can’t move or fall off table (use a jack-stand)
All team members clear of moving parts
Connect either WiFi keys or tether cable between the joystick and the Cortex controller.
Make sure Cortex switch is in OFF position.
Attach a charged battery.
Turn on joystick (if not using tether).
Turn Cortex switch to ON position.
For WiFi comm, link should establish in ~10 sec
Test robot operations with transmitter.

87. Other Useful Functions
Programming Example
Other Useful Functions

88. Other Useful Functions
Program Flow
If Conditional
Else-IF Conditional
Else Conditional
While Loop While condition is True …
For Loop Repeat for X number of times
Comment PLEASE COMMENT!

89. Other Useful Functions
Inputs
Digital Input…Gets Status of Digital Input
Outputs
Motor Module…Directly send value to motor
Servo Module…Directly send value to servo

90. Other Useful Functions
Joystick
Arcade – 2 Motor
Use Arcade style joystick inputs and drive 2 motors
Tank-2 Motor
Use Tank style joystick inputs and 2 drive motors
Joystick to Motor
Take input from 1 joystick and send it to motor

91. Other Useful Functions
Joystick
Joystick to Motor & Limit
Take joystick value straight to motor if not at limit
Joystick to Servo
Take a joystick value and send it to a servo
Joystick Digital to Motor
Select 2 speeds for a motor based on joystick buttons pressed
Joystick Digital to Motor & Limit
Select 2 speeds for a motor based on joystick buttons pressed, unless limit is reached

92. Other Useful Functions
Joystick
Joystick Digital to Servo
Select one of 2 positions of a servo based on 2 buttons on the joystick
Get Joystick to Analog
Retrieves a joystick value to a variable
Get Joystick to Digital
Retrieves a joystick button to a variable

93. Appendix

94. Appendix: Resources Online resources/documentation
BEST Public Message Board
Must register for login account
Share ideas, resolve issues, …

95. Appendix: Resources Official Q&A “Control System” Category VEX Forum
Use “Official Q&A” page during contest for “rules specific” questions
Is this legal?
VEX Forum
Technical questions about VEX equipment
easyC and RobotC dedicated forums included here

96. Appendix: Resources Robotevents BEST Forum
Dedicated user forum for BEST Robotics
Must register for a login account

97. Appendix: Re-sync Controller
Turn off Cortex and Joystick
Connect A-A USB cable to Cortex and Joystick
Turn on Joystick OR Cortex
Wait for Green Vexnet Light on both Joystick and Cortex
Turn off both Joystick and Cortex
Disconnect cables

98. Appendix - Status Lights
joystick battery status
robot battery status
comm. link status
Game status (not used by BEST)
Green battery – good charge
Yellow battery - dying
Red battery – dead
Green VEXnet – comm. established
Yellow VEXnet – searching
Lights on the controller and the joystick are the same

99. Appendix – Team Tips
Tin motor wires with solder before attaching to screw terminals since frayed stranded wires can cause a short.
Do NOT solder wires to Cortex connectors!
Sensor cables, servo wires, and servo extensions are all keyed in correct orientation; insert and remove carefully to avoid destroying connectors.
Tighten screws on motor and sensor connector cables so that wires are not loose and do not pull out.
Mount Cortex to robot using #8 screws through holes provided; be careful not to over tighten.
Avoid “hot insertion” of USB Keys.
You may operate tethered by removing the USB WiFi key and connecting a USB A-A cable between joystick and Cortex.

100. Appendix - Joystick Calibration
If the motors hum or creep (sticks not returning to zero), the joystick may need to be recalibrated
Calibration procedure (as extracted from the easyC help file)
1) The Joystick must be "Linked" to the Cortex Microcontroller using the VEXnet Keys.
2) Hold the "6U" Back Switch depressed.
3) 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.
4) Hold both Switches depressed until you see the Joystick LED Flash RED and GREEN - you can now release both Switches.
a. There is a 10 second time limit to complete the following steps 5 and 6.
5) Now move both Joystick Pots to the maximum position desired in all 4 directions - Up, Back, Left, and Right.
a. If a movement is not detected in all 4 directions, a timeout will occur after about 10 seconds and the Cal Mode will be discontinued and the VEXnet LED will briefly Flash Red.
b. The Joystick LED will continue to Flash RED and GREEN during the calibration process.
6) After movement is detected in all 4 directions, the Joystick LED will be ON and Solid GREEN.
a. To "Save" the Calibration, depress and release the "8U" Top Switch Button.
b. If the calibration is accepted and Saved, the Joystick LED will start Flashing Fast GREEN for a few seconds.
c. If the Calibration is not Saved, a timeout will occur after about 10 seconds and the Cal Mode will be discontinued and the VEXnet LED will briefly Flash Red.
d. To cancel a calibration, depress and release the "7U" Top Switch Button. The Cal Mode will be discontinued and the VEXnet LED will briefly Flash Red.
e. If the Cal Mode is discontinued or saved, the Joystick LEDs will resume their normal function after the VEXnet LED briefly Flashes.

101. Appendix – Default Program
Motor/Servo
Output
Joystick
Channel
Motor Limits
Positive Direction
Negative Direction
Motor 1
NOT USED
None
Motor 2
(Arcade Right)
Channel 1 (Lt, Rt)
Channel 2 (Fwd/Rev)
Motor 3
Channel 1
Digital Input 1
Digital Input 2
Motor 4
Channel 2
Digital Input 3
Digital Input 4
Motor 5
Channel 3
Digital Input 5
Digital Input 6
Motor 6
Channel 4
Digital Input 7
Digital Input 8
Motor 7
Channel 3 Inverse
Motor 8
Channel 4 Inverse
Motor 9
(Arcade Left)
Motor 10