CTR Electronics CANifier User manual

CANifier User’s Guide www.ctr-electronics.com 10/8/2017
Cross The Road Electronics Page 1 10/8/2017
CANifier
User’s Guide
Revision 1.0
Cross The Road Electronics
www.ctr-electronics.com

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Table of Contents
1. What is CANifier?.......................................................................................................................................................................... 4
1.1. Features ................................................................................................................................................................................ 5
1.2. Pin Descriptions .................................................................................................................................................................... 6
1.3. Electrical Specifications......................................................................................................................................................... 7
1.3.1. Voltage Rail Dropout Plots. ........................................................................................................................................... 7
1.4. Electrical Schematic .............................................................................................................................................................. 8
1.5. LEDs....................................................................................................................................................................................... 9
1.5.1. LED Channel LEDs (3)..................................................................................................................................................... 9
1.5.2. Status LED States (2)...................................................................................................................................................... 9
2. Installation .................................................................................................................................................................................. 11
2.1. Installing CAN Bus and Power leads.................................................................................................................................... 11
2.2. Wiring Common-Anode LED Strip ....................................................................................................................................... 12
2.3. Wiring remaining signals..................................................................................................................................................... 12
2.3.1. Sensor examples ......................................................................................................................................................... 13
2.4. Test CANifier assembly and wiring...................................................................................................................................... 15
2.5. Enclose/Insulate CANifier assembly.................................................................................................................................... 16
3. Phoenix Framework (Software) .................................................................................................................................................. 17
3.1. Software Examples.............................................................................................................................................................. 17
3.2. Status Frame Rates ............................................................................................................................................................. 17
3.3. Custom Platforms................................................................................................................................................................ 17
3.4. HERO LifeBoat / roboRIO Web-based configuration........................................................................................................... 18
4. Functional Limitations................................................................................................................................................................. 19
4.1. Future features to be implemented.................................................................................................................................... 19
4.2. When hot-swapping certain sensors, CANifier may reset................................................................................................... 19
4.3. roboRIO Self-test will be added in future............................................................................................................................ 19
4.4. Reverse Limit signal is missing ESD diode. .......................................................................................................................... 19
4.5. Silkscreen suggests max input voltage is 33V. Vdd-max is 28V.......................................................................................... 19
5. Frequently Asked Questions (FAQ) ............................................................................................................................................. 20
5.1. Certain features are not working, but this document indicates they should work............................................................. 20
5.2. Signals updates seem slow. There is stair-stepping in my signal plots............................................................................... 20
6. Firmware (CRF) Version History .................................................................................................................................................. 21
7. Revision History .......................................................................................................................................................................... 21

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TO OUR VALUED CUSTOMERS
It is our intention to provide our valued customers with the best documentation possible to
ensure successful use of your CTRE products. To this end, we will continue to improve our
publications, examples, and support to better suit your needs.
If you have any questions or comments regarding this document, or any CTRE product, please
contact [e-mail]
To obtain the most recent version of this document, please visit
www.ctr-electronics.com.

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1. What is CANifier?
The CTR Electronics CANifier is a CAN-controlled multipurpose LED and General Purpose Input/Output (GPIO)
controller. CANifier also supports a variety of sensors including Quadrature, Limit Switch, SPI, I2C, and PWM
input/output.
CANifier is designed to “CAN-ify”robot control system components that traditionally do not take advantage of CAN
bus. This allows robot developers already using CAN bus to further expand their capabilities.
Example users are…
-Commercial Robots developed using
the CTRE HERO Control System.
-Robots developed for FRC
Competition (or similar).
-Academic robot courses/design
projects.
-Rapid Prototyping (need to quickly
add another sensor)
Example use-cases solved by CANifier…
-Integrates PWM sensors like LIDAR/Sonar into a CTRE-HERO/FRC/CAN Bus control system.
-Add more sensors into the FRC CAN bus without involving the roboRIO (no hardware SPI/I2C drivers to
struggle with). Native support coming in the CTRE Phoenix Framework.
-Allows direct communication between external sensors and various CTRE CAN products for future out-of-
box features that “just work”.
-Allows control of PWM motor controllers (1) like Victor SP via CAN bus commands through CANifier.
-LED Strip control via CAN bus.
-Integrate RC Radio control (PWM) into CTRE-HERO/FRC/CAN Bus control system.
-Sensors located far from central robot controller can instead tap into the CAN bus.
Note 1: FRC Teams must confirm what is deemed legal when using PWM motor controllers in competition. Typically, FRC rules require PWM
Motor controllers to be wired directly to roboRIO.

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1.1. Features
CAN bus controlled and field-upgradeable
3x LED channel drivers
oIndividual RGB control with 10bit resolution.
Support for many sensor types, including:
oSRX Mag Encoder / quadrature encoders
oLimit switches
oPixy/CMUcam5
oPulse width ultrasonic (e.g. MaxBotix MB1013)
oLIDAR-Lite v3
oTalon Tach
oDigital Sharp distance sensors
Outputs for common devices, including:
oPWM motor controllers
oSmall hobby servos
oPWM LED controllers
oAny PWM-controlled device
Electro-static Discharge (ESD) protection on exposed pins
Future features…
oSeveral sensor types supported directly in firmware.
oSPI/I2C-over-CANBus software driver.
oDirect communication with CTRE CAN Devices for a variety of features.

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1.2. Pin Descriptions
The CANifier has a multitude of I/O pins. All pins are counted as GPIO (General Purpose Input/Output) except for
power supply pins (5V, GND, 3.3V, VDD).
Pin #
Name
Function
1
SDA
I2C Data pin
2
SCL
I2C Clock pin
3
5V
5V output
4
QUAD A
Quadrature channel A
5
GND
Ground
6
QUAD B
Quadrature channel B
7
INDEX
Quadrature Index
8
LIMF
Limit Switch Forward
9
GND
Ground
10
LIMR
Limit Switch Reverse
11
GND
Ground
12
CS/PWM3
SPI Chip Select / PWM input 3
13
CLK/PWM0
SPI Clock / PWM input 0
14
MOSI/PWM1
SPI Data Out / PWM input 1
15
MISO/PWM2
SPI Data In / PWM input 2
16
5V
5V output
17
5V
5V output
18
3.3V
3.3V output
19
3.3V
3.3V output
20
GND
Ground
21
GND
Ground
CANH
CAN High
CANL
CAN Low
V+
LED Source Voltage (Common anode)
A
LED Channel A (cathode)
B
LED Channel B (cathode)
C
LED Channel C (cathode)
Backside
VDD
Supply Voltage
Backside
GND
Ground

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1.3. Electrical Specifications
Note 1: A silkscreen error implies a maximum VDD of 33V. The real maximum VDD is 28V. VDD limits are for guaranteeing full functionality.
Note 2: See Section 1.3.1 (Figure 1.1. 5V rail dropout)
Note 3: See Section 1.3.1 (Figure 1.2. 3.3V rail dropout)
Note 4: See schematic for information on series resistors
Note 5: This will be configurable in future updates.
Note 6: All pins have TVS diodes for ESD protection except for LIMR.
1.3.1. Voltage Rail Dropout Plots.
Symbol
Parameter
Condition
Min
Typ
Max
Unit
Tamb
Ambient temperature
-40
+125
°C
Vdd
Supply voltage
7
28 (1)
V
Isupp
Supply Current
7.0V < Vdd < 28.0V
12
24
mA
Vdrop_5V
5V rail dropout voltage
At Vdd
6.5 (2)
V
Vdrop_3.3V
3.3V rail dropout voltage
At Vdd
3.9 (3)
V
Vdrop_CAN
CAN dropout voltage
At Vdd
5.2
V
Imax_5V
Max continuous 5V current draw
500
mA
Imax_3.3V
Max continuous 3.3V current draw
100
mA
Imax_ABC
Max sink current per LED channel
3.5
A
GPIO Specs
VoL
Low level output voltage
GND+0.4
V
VoH
High level output voltage
2.8
3.3
V
Io
Source/Sink current per output pin
3
mA
RGPIO
GPIO series resistance (4)
22
Ω
ViL
Low level input voltage
-0.3
0.2
V
ViH
High level input voltage
2.7
5.5
V
fPWM_ABC
A, B, and C PWM switching frequency
1
kHz
fPWM_OUT_0123
PWM 0-3 Period (5)
As output
4.2
ms
fPWM_IN_0123
Pulse Width Measurement Accuracy
As inputs
250
ns
Default internal pull mode
As inputs
Pullup
ESD Rating
ESD Protection Contact Discharge (6)
±8
kV
ESD Protection Air-Gap Discharge (6)
±8
kV
Figure 1.1. 5V rail dropout voltage
Figure 1.2. 3.3V rail dropout voltage

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1.4. Electrical Schematic
Note that V+, 5V, 3.3V, GND, CANH, and CANL have exposed pads on the PCB

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1.5. LEDs
CANifier has multiple LEDs…
-Two bicolor LEDs for CAN and control status.
-Three red LEDs to instrument the individual LED channel outputs.
1.5.1. LED Channel LEDs (3)
Each LED channel has a dedicated red LED that will illuminate if the channel is
modulated (partially or full on). This can be used to confirm if the CANifier is
commanded to turn on LED Channels.
1.5.2. Status LED States (2)
The CANifier features two bicolor LEDs that indicate the status of the CANifier. This feature can be used to confirm
proper operation. The table below shows the possible color states and their respective operation.
Note 1: LEDs Alternate –Status LEDs are always different colors. The (2X) LEDs will swap colors when blinking.
Blink Codes
LEDs
Colors
CANifier State
None
None
No Power is being applied to CANifier
LEDs Alternate (1)
Off/Red
CAN bus is not detected
Check CAN cabling to the CANifier, check other devices
on CAN bus to confirm that the bus is operational
LEDs Alternate (1)
Off/Orange
CAN bus detected but no commands are being received.
Most likely no CANifier object was created in software.
LEDs Alternate (1)
Switching between Red/Orange and
Orange/Red
Damaged Hardware
LED1 Only
“closest” to
M+/V+
Green/Orange
In Boot-loader
LEDs Alternate (1)
Blinking Green
CAN is connected, the CANifier is being controlled by
robot controller.
Channel C
Channel B
Channel A

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1.5.2.1. Status LEDs –Damaged Hardware
The CANifier can detect certain types of hardware damage. When damage is detected the CANifier will blink in a
periodic fashion as mentioned in the table above. This is also illustrated below…
Note that the LEDs never turn off when indicating this failure mode. Each LED is always red or orange at any
moment. The orange/red LED pattern will continue to blink this pattern with no intermittent change in LED
activity.
If this is being witnessed, ensure that the LED pattern isn’t simply an intermittent red LED blink superimposed on
to the typical orange LED pattern. This is typically observed when there is an intermittent wiring issue or when
two or more CANifiers with common device IDs are present on the CAN bus. Both can be checked by connecting
the CANifier directly to the robot controller. Do not connect any other CAN devices and avoid complex wire
harness strategies.
Erratic red and orange blink patterns are typically caused by intermittent cable issues, or not properly configuring
the device IDs of the CANifiers. Such LED patterns should not be misconstrued as the damaged LED code
mentioned above.

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2. Installation
Below is the typical procedure for installing a CANifier.
2.1. Installing CAN Bus and Power leads
Prepare wires ahead of time to solder to CANifier.
Generally, every use case will require power and
ground wire leads, and CAN bus.
Twist/rat-tail splice two CAN pigtail wire pairs so
that it can be easily soldered. This allows for
daisy chaining of CAN bus devices.
Pre-tin the stripped CAN bus and power/ground wire ends and respective
solder pads the CANifier.
Hold pre-tinned solder lead over the pad and apply heat via the soldering iron. Solder joint
should appear shiny after cooling with no gaps or discontinuities on the joint surface.

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2.2. Wiring Common-Anode LED Strip
CANifier is designed to be mated directly or near-proximity to the connection point of a common-anode LED strip.
Depending on what is available on the LED strip end, an additional pin header can be solder to facilitate wiring to
the CANifier, or the LED strip can be directly soldered to the CANifier pads.
Note the signal orientation (from top to bottom) of LED Strip (Blue, Red, Green, V+) to CANifier (C, B, A, V+).
Ensure that the common + rail of the LED Strip connects to the V+ hole/pad on the CANifier.
Warning: Be sure to select the proper wire gauge for the LED strip. LED strips can draw several Amperes, and
selection of a thin gauge may increase the risk of fire. PDP breakers/fuses do not improve this problem since
they do not open until 10-40A of continuous draw (depending on which fuse/breaker type). If in doubt, feel the
wire harness after several minutes of continuous use to confirm the presence of excessive heat. If excessive
heat is detected, consider using a larger gauge.
2.3. Wiring remaining signals.
Depending on use-case, additional signals may need to be wired.
The remaining signals that can be wired via the solder holes are…
-Quadrature Encoder.
-I2C.
-SPI.
-PWM (input and output).
-Limit Switches.
-3.3V/5V/GND for peripherals powered by CANifier.
Strip ~20AWG wire and pass thru the
100mil through-holes. Apply sufficient
solder on opposite side and flush-cut the
excess stripped wire.
Alternatively, a 100-mil spaced header
could be soldered on for convenient
socket/breadboard reuse.
However, in a critical application (mobile robotics for example) a soldered connection is typically far more robust.

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2.3.1. Sensor examples
Various sensor example configurations are documented below.
2.3.1.1. LIDAR Lite V3 Distance Sensor
More information can be found in the LIDAR Lite V3 Operation Manual.
Be sure to tie pull down resistor to ensure LIDAR continuously samples distance.
2.3.1.2. Quadrature Encoder
5V Quadrature encoder example below. Quadrature INDEX can be wired as well if application requires it.

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2.3.1.3. Limit Switch Inputs

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2.4. Test CANifier assembly and wiring
Before installing CANifier into the final enclosure or heat shrink tubing, test CANifier in isolation. This is the best
opportunity to field-upgrade CANifier to latest firmware, and test peripherals to ensure wiring is correct before
burying the CANifier assembly into the final robot/platform.
It is recommended to perform basic functional testing on all control system components as soon as they are
received. Many of these components have manufacture warranties that can expire if a boxed component is left
unused/untested for an excessive period. Spare/backup components meant for competition should be checked
in advance as well. This will ensure the best chance of success during competition events where repair time is
limited between matches.
If the 5V or 3.3V rail is used to power a sensor, confirm the sensor is functional and the rails meet the expected
voltages with a voltmeter.
Below, CANifier is directly inserted into a HERO with a simple C# app that streams thru LED strip colors.
Example source is available on www.ctr-electronics.com and www.github.com/CrossTheRoadElec

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2.5. Enclose/Insulate CANifier assembly
The recommended approach to insulate CANifier is to shroud entire wire assembly in 1” heat shrink tubing.
Insert assembly into one side of a precut heat
shrink tubing.
Heat shrink should cover all
exposed electrical areas of
CANifier and LED strip.
After applying heat to heat shrink tubing, neatly wrap and separate the harnesses into their logical sub groups.
Illustrated below are two pigtails for CAN bus, power leads (to PDP/power source), and wire harness for
PWMs/sensors/etc.
Alternatively, the CANifier can be mounted to a fixed location using a 3D
printed enclosure.
Fixed mounting is accomplished via the two mounting holes in the CANifier.
These holes are 0.125” in diameter nominally, and act as clearance for a 4-40
or M3 screw. A case for the CANifier in STEP and STL formats is available on ctr-
eletronics.com to facilitate fixed mounting while covering the exposed pads.
Use any length 4-40 or M3 screw to attach the CANifier to your mounting
surface. Ensure that there is no contact between any exposed pads and the
mounting surface. Plastic spacers can be used to isolate the CANifier from the
surface. The CANifier can also be mounted with double-side tape, but ensure
that the tape is nonconductive and that wires are soldered onto the CANifier
before mounting.

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3. Phoenix Framework (Software)
Phoenix Framework is the CTRE Software API for CTRE CAN devices, including CANifier. The current version is in Alpha
development and can be found at the CTRE site.
http://www.ctr-electronics.com/control-system/hro.html#product_tabs_technical_resources
Support will include the following platforms…
-HERO Development board –C#
-Java FRC roboRIO
-C++ FRC roboRIO
-LabVIEW FRC roboRIO
3.1. Software Examples
CANifier examples can be found in the following GitHub repositories (or find on the CTRE CANifier product’s page).
HERO and FRC programming languages…
https://github.com/CrossTheRoadElec/Phoenix-Examples-Languages
FRC LabVIEW…
https://github.com/CrossTheRoadElec/Phoenix-Examples-LabVIEW
3.2. Status Frame Rates
After CANifier boots application firmware, it transmits the following signals at their respective rates…
Default Signal CAN Bus Frame Rates
Status Frame
Default Period (ms)
Signals
Status 1
100
LED Duty Cycles, Battery Voltage, Faults
Status 2
10
Quadrature, Digital Inputs
Status 3
100
PWM Channel 0 measurement
Status 4
100
PWM Channel 1 measurement
Status 5
100
PWM Channel 2 measurement
Status 6
100
PWM Channel 3 measurement
These frame rates can be adjusted with the software API in the Phoenix Framework.
Example code snippet below…
3.3. Custom Platforms
Portions of the Phoenix Framework are open source, to allow developers to port the CAN communication to a custom protocol.
Check the Phoenix repositories on CTRE’s GitHub for more information.

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3.4. HERO LifeBoat / roboRIO Web-based configuration
For CANifier(s) to appear in the roboRIO Web-based
configuration page, run the latest HERO LifeBoat.
Connect roboRIO with USB cable, and press the “Update RIO
Web-based Config” button.
Afterwards, CANifier(s) will appear in the
device list of the roboRIO.
“Light Device LED” can be used to confirm
which CANifier has which device ID.
No two CANifiers can have the same device
ID.
CANifier firmware can be updated via
roboRIO in this view as well.
LifeBoat can also be used to update LifeBoat or change
Device ID.

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4. Functional Limitations
4.1. Future features to be implemented.
Current version of firmware (CANifier-Application-0.9.crf) supports the following features…
-Pulse width decoding on PWM 0, 1, 2, 3. (Tested with LIDAR v3, various hobby RC Radios, CTRE Mag Sensor, etc.).
-PWM output on PWM 0, 1, 2. (Tested with Talon SRX in PWM mode).
-General purpose digital inputs on all pins.
-General purpose digital outputs on all pins.
-Common anode LED strip control.
-PWM outputs have a fixed period of 4.2ms.
Future versions of firmware will include…
-General I2C/SPI support over CAN bus.
-NeoPixel compliant protocol for addressable LED strips.
-PWM output on PWM 3 (CS)
-Custom control of PWM output period.
… and future CAN bus features that communicate directly with Talon SRXs/Pigeon-IMUs/etc.
4.2. When hot-swapping certain sensors, CANifier may reset.
Certain sensors may have an in-rush (on-boot) current draw that exceeds the sensor’s typical continuous current draw.
An example of this is the LIDAR-Lite V3 sensor, which has an initial current draw far greater than 500 mA.
Thus, disconnecting/reconnecting the LIDAR Lite sensor while CANifier is powered may cause CANifier to reboot as the supply
rail may reset.
Since hot-swapping sensors is typically not done during robotic movement, no workaround is needed beyond ensuring robust
connectivity with sensors.
4.3. roboRIO Self-test will be added in future.
When Self-Test button is pressed, Web-based configuration will report “not supported in firmware”.
This will be added in a future update. The other features in the roboRIO Web-Based Configuration currently function after
using HERO LifeBoat to update the roboRIO.
4.4. Reverse Limit signal is missing ESD diode.
The current hardware version of CANifier does not have the ESD diode populated for the reverse limit signal.
Though there is protection (series 22Ω resistor), this means LIMR does not meet the full 8KV ESD rating.
This is only a concern during direct ESD strikes occurring on this specific trace.
Regardless, users should take precautions to prevent ESD strikes to electronics under all circumstances.
When approaching robot chassis, be sure to discharge to robot by touching robot chassis before handling electronics.
When handling electronics, take measures to ensure handler is grounded via a wrist strap or grounded work surface.
4.5. Silkscreen suggests max input voltage is 33V. Vdd-max is 28V.
Silkscreen is incorrect. Max input voltage is 28V.

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5. Frequently Asked Questions (FAQ)
5.1. Certain features are not working, but this document indicates they should work.
Update to the latest CANifier firmware. CANifier ship firmware is 0.4 which is missing most features.
5.2. Signals updates seem slow. There is stair-stepping in my signal plots.
Speed up the CAN frame rates by following Section 3.2.