This is the description of the Mathematica API bindings for the CAN Bricklet 2.0. General information and technical specifications for the CAN Bricklet 2.0 are summarized in its hardware description.
An installation guide for the Mathematica API bindings is part of their general description.
The example code below is Public Domain (CC0 1.0).
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 | Needs["NETLink`"]
LoadNETAssembly["Tinkerforge",NotebookDirectory[]<>"../../.."]
host="localhost"
port=4223
uid="XYZ"(*Change XYZ to the UID of your CAN Bricklet 2.0*)
(*Create IPConnection and device object*)
ipcon=NETNew["Tinkerforge.IPConnection"]
can=NETNew["Tinkerforge.BrickletCANV2",uid,ipcon]
ipcon@Connect[host,port]
(*Configure transceiver for loopback mode*)
can@SetTransceiverConfiguration[1000000,625,
Tinkerforge`BrickletCANV2`TRANSCEIVERUMODEULOOPBACK]
(*Callback function for frame read callback*)
FrameReadCB[sender_,frameType_,identifier_,data_]:=
Module[{},
If[frameType==Tinkerforge`BrickletCANV2`FRAMEUTYPEUSTANDARDUDATA,Print["Frame Type: Standard Data"]];
If[frameType==Tinkerforge`BrickletCANV2`FRAMEUTYPEUSTANDARDUREMOTE,Print["Frame Type: Standard Remote"]];
If[frameType==Tinkerforge`BrickletCANV2`FRAMEUTYPEUEXTENDEDUDATA,Print["Frame Type: Extended Data"]];
If[frameType==Tinkerforge`BrickletCANV2`FRAMEUTYPEUEXTENDEDUREMOTE,Print["Frame Type: Extended Remote"]];
Print["Identifier: "<>ToString[identifier]];
Print["Data (Length: "<>ToString[N[Length[data]]]<>"): "<>ToString[data]]
]
AddEventHandler[can@FrameReadCallback,FrameReadCB]
(*Enable frame read callback*)
can@SetFrameReadCallbackConfiguration[True]
(*Write standard data frame with identifier 1742 and 3 bytes of data*)
can@WriteFrame[Tinkerforge`BrickletCANV2`FRAMEUTYPEUSTANDARDUDATA,1742,{42,23,17}]
Input["Click OK to exit"]
can@SetFrameReadCallbackConfiguration[False]
ipcon@Disconnect[]
ReleaseNETObject[can]
ReleaseNETObject[ipcon]
|
Generally, every function of the Mathematica bindings that returns a value can
throw a Tinkerforge.TimeoutException
. This exception gets thrown if the
device did not respond. If a cable based connection is used, it is
unlikely that this exception gets thrown (assuming nobody plugs the
device out). However, if a wireless connection is used, timeouts will occur
if the distance to the device gets too big.
Since .NET/Link does not support multiple return values directly, we use the
out
keyword to return multiple values from a function. For further
information about the out
keyword in .NET/Link see the corresponding
Mathematica .NET/Link documentation.
The namespace for all Brick/Bricklet bindings and the IPConnection is
Tinkerforge.*
.
BrickletCANV2
[uid, ipcon] → canV2¶Parameters: |
|
---|---|
Returns: |
|
Creates an object with the unique device ID uid
:
canV2=NETNew["Tinkerforge.BrickletCANV2","YOUR_DEVICE_UID",ipcon]
This object can then be used after the IP Connection is connected.
The .NET runtime has built-in garbage collection that frees objects that are no longer in use by a program. But because Mathematica can not automatically tell when a Mathematica "program" doesn't use a .NET object anymore, this has to be done by the program. For this the ReleaseNETObject[] function is used in the examples.
For further information about object management in .NET/Link see the corresponding Mathematica .NET/Link documentation.
BrickletCANV2
@
WriteFrame
[frameType, identifier, {data1, data2, ...}] → success¶Parameters: |
|
---|---|
Returns: |
|
Writes a data or remote frame to the write queue to be transmitted over the CAN transceiver.
The Bricklet supports the standard 11-bit (CAN 2.0A) and the additional extended
29-bit (CAN 2.0B) identifiers. For standard frames the Bricklet uses bit 0 to 10
from the identifier
parameter as standard 11-bit identifier. For extended
frames the Bricklet uses bit 0 to 28 from the identifier
parameter as
extended 29-bit identifier.
The data
parameter can be up to 15 bytes long. For data frames up to 8 bytes
will be used as the actual data. The length (DLC) field in the data or remote
frame will be set to the actual length of the data
parameter. This allows
to transmit data and remote frames with excess length. For remote frames only
the length of the data
parameter is used. The actual data
bytes are
ignored.
Returns true if the frame was successfully added to the write queue. Returns
false if the frame could not be added because write queue is already full or
because the write buffer or the write backlog are configured with a size of
zero (see SetQueueConfiguration[]
).
The write queue can overflow if frames are written to it at a higher rate
than the Bricklet can transmitted them over the CAN transceiver. This may
happen if the CAN transceiver is configured as read-only or is using a low baud
rate (see SetTransceiverConfiguration[]
). It can also happen if the CAN
bus is congested and the frame cannot be transmitted because it constantly loses
arbitration or because the CAN transceiver is currently disabled due to a high
write error level (see GetErrorLog[]
).
The following constants are available for this function:
For frameType:
BrickletCANV2
@
ReadFrame
[out success, out frameType, out identifier, out {data1, data2, ...}] → Null¶Output Parameters: |
|
---|
Tries to read the next data or remote frame from the read queue and returns it.
If a frame was successfully read, then the success
return value is set to
true and the other return values contain the frame. If the read queue is
empty and no frame could be read, then the success
return value is set to
false and the other return values contain invalid data.
The identifier
return value follows the identifier format described for
WriteFrame[]
.
The data
return value can be up to 15 bytes long. For data frames up to the
first 8 bytes are the actual received data. All bytes after the 8th byte are
always zero and only there to indicate the length of a data or remote frame
with excess length. For remote frames the length of the data
return value
represents the requested length. The actual data
bytes are always zero.
A configurable read filter can be used to define which frames should be
received by the CAN transceiver and put into the read queue (see
SetReadFilterConfiguration[]
).
Instead of polling with this function, you can also use callbacks. See the
SetFrameReadCallbackConfiguration[]
function and the FrameReadCallback
callback.
The following constants are available for this function:
For frameType:
BrickletCANV2
@
SetTransceiverConfiguration
[baudRate, samplePoint, transceiverMode] → Null¶Parameters: |
|
---|
Sets the transceiver configuration for the CAN bus communication.
The CAN transceiver has three different modes:
The following constants are available for this function:
For transceiverMode:
BrickletCANV2
@
GetTransceiverConfiguration
[out baudRate, out samplePoint, out transceiverMode] → Null¶Output Parameters: |
|
---|
Returns the configuration as set by SetTransceiverConfiguration[]
.
The following constants are available for this function:
For transceiverMode:
BrickletCANV2
@
SetQueueConfiguration
[writeBufferSize, writeBufferTimeout, writeBacklogSize, {readBufferSizes1, readBufferSizes2, ...}, readBacklogSize] → Null¶Parameters: |
|
---|
Sets the write and read queue configuration.
The CAN transceiver has 32 buffers in total in hardware for transmitting and receiving frames. Additionally, the Bricklet has a backlog for 768 frames in total in software. The buffers and the backlog can be freely assigned to the write and read queues.
WriteFrame[]
writes a frame into the write backlog. The Bricklet moves
the frame from the backlog into a free write buffer. The CAN transceiver then
transmits the frame from the write buffer to the CAN bus. If there are no
write buffers (write_buffer_size
is zero) or there is no write backlog
(write_backlog_size
is zero) then no frames can be transmitted and
WriteFrame[]
returns always false.
The CAN transceiver receives a frame from the CAN bus and stores it into a
free read buffer. The Bricklet moves the frame from the read buffer into the
read backlog. ReadFrame[]
reads the frame from the read backlog and
returns it. If there are no read buffers (read_buffer_sizes
is empty) or
there is no read backlog (read_backlog_size
is zero) then no frames can be
received and ReadFrame[]
returns always false.
There can be multiple read buffers, because the CAN transceiver cannot receive
data and remote frames into the same read buffer. A positive read buffer size
represents a data frame read buffer and a negative read buffer size represents
a remote frame read buffer. A read buffer size of zero is not allowed. By
default the first read buffer is configured for data frames and the second read
buffer is configured for remote frame. There can be up to 32 different read
buffers, assuming that no write buffer is used. Each read buffer has its own
filter configuration (see SetReadFilterConfiguration[]
).
A valid queue configuration fulfills these conditions:
write_buffer_size + abs(read_buffer_size_0) + abs(read_buffer_size_1) + ... + abs(read_buffer_size_31) <= 32
write_backlog_size + read_backlog_size <= 768
The write buffer timeout has three different modes that define how a failed frame transmission should be handled:
The current content of the queues is lost when this function is called.
BrickletCANV2
@
GetQueueConfiguration
[out writeBufferSize, out writeBufferTimeout, out writeBacklogSize, out {readBufferSizes1, readBufferSizes2, ...}, out readBacklogSize] → Null¶Output Parameters: |
|
---|
Returns the queue configuration as set by SetQueueConfiguration[]
.
BrickletCANV2
@
SetReadFilterConfiguration
[bufferIndex, filterMode, filterMask, filterIdentifier] → Null¶Parameters: |
|
---|
Set the read filter configuration for the given read buffer index. This can be used to define which frames should be received by the CAN transceiver and put into the read buffer.
The read filter has four different modes that define if and how the filter mask and the filter identifier are applied:
The filter mask and filter identifier are used as bit masks. Their usage depends on the mode:
The filter mask and filter identifier are applied in this way: The filter mask is used to select the frame identifier bits that should be compared to the corresponding filter identifier bits. All unselected bits are automatically accepted. All selected bits have to match the filter identifier to be accepted. If all bits for the selected mode are accepted then the frame is accepted and is added to the read buffer.
Filter Mask Bit | Filter Identifier Bit | Frame Identifier Bit | Result |
---|---|---|---|
0 | X | X | Accept |
1 | 0 | 0 | Accept |
1 | 0 | 1 | Reject |
1 | 1 | 0 | Reject |
1 | 1 | 1 | Accept |
For example, to receive standard frames with identifier 0x123 only, the mode can be set to Match-Standard-Only with 0x7FF as mask and 0x123 as identifier. The mask of 0x7FF selects all 11 identifier bits for matching so that the identifier has to be exactly 0x123 to be accepted.
To accept identifier 0x123 and identifier 0x456 at the same time, just set filter 2 to 0x456 and keep mask and filter 1 unchanged.
There can be up to 32 different read filters configured at the same time,
because there can be up to 32 read buffer (see SetQueueConfiguration[]
).
The default mode is accept-all for all read buffers.
The following constants are available for this function:
For filterMode:
BrickletCANV2
@
GetReadFilterConfiguration
[bufferIndex, out filterMode, out filterMask, out filterIdentifier] → Null¶Parameters: |
|
---|---|
Output Parameters: |
|
Returns the read filter configuration as set by SetReadFilterConfiguration[]
.
The following constants are available for this function:
For filterMode:
BrickletCANV2
@
GetErrorLog
[out transceiverState, out transceiverWriteErrorLevel, out transceiverReadErrorLevel, out transceiverStuffingErrorCount, out transceiverFormatErrorCount, out transceiverACKErrorCount, out transceiverBit1ErrorCount, out transceiverBit0ErrorCount, out transceiverCRCErrorCount, out writeBufferTimeoutErrorCount, out readBufferOverflowErrorCount, out {readBufferOverflowErrorOccurred1, readBufferOverflowErrorOccurred2, ...}, out readBacklogOverflowErrorCount] → Null¶Output Parameters: |
|
---|
Returns information about different kinds of errors.
The write and read error levels indicate the current level of stuffing, form, acknowledgement, bit and checksum errors during CAN bus write and read operations. For each of this error kinds there is also an individual counter.
When the write error level extends 255 then the CAN transceiver gets disabled and no frames can be transmitted or received anymore. The CAN transceiver will automatically be activated again after the CAN bus is idle for a while.
The write buffer timeout, read buffer and backlog overflow counts represents the number of these errors:
SetQueueConfiguration[]
).SetReadFilterConfiguration[]
) can help to reduce the amount of
received frames. This count is not exact, but a lower bound, because the
Bricklet might not able detect all overflows if they occur in rapid succession.ReadFrame[]
function. Using the FrameReadCallback
callback ensures that the read backlog
can not overflow.The read buffer overflow counter counts the overflows of all configured read
buffers. Which read buffer exactly suffered from an overflow can be figured
out from the read buffer overflow occurrence list
(read_buffer_overflow_error_occurred
). Reading the error log clears the
occurence list.
The following constants are available for this function:
For transceiverState:
BrickletCANV2
@
SetCommunicationLEDConfig
[config] → Null¶Parameters: |
|
---|
Sets the communication LED configuration. By default the LED shows CAN-Bus traffic, it flickers once for every 40 transmitted or received frames.
You can also turn the LED permanently on/off or show a heartbeat.
If the Bricklet is in bootloader mode, the LED is off.
The following constants are available for this function:
For config:
BrickletCANV2
@
GetCommunicationLEDConfig
[] → config¶Returns: |
|
---|
Returns the configuration as set by SetCommunicationLEDConfig[]
The following constants are available for this function:
For config:
BrickletCANV2
@
SetErrorLEDConfig
[config] → Null¶Parameters: |
|
---|
Sets the error LED configuration.
By default (show-transceiver-state) the error LED turns on if the CAN
transceiver is passive or disabled state (see GetErrorLog[]
). If
the CAN transceiver is in active state the LED turns off.
If the LED is configured as show-error then the error LED turns on if any error occurs. If you call this function with the show-error option again, the LED will turn off until the next error occurs.
You can also turn the LED permanently on/off or show a heartbeat.
If the Bricklet is in bootloader mode, the LED is off.
The following constants are available for this function:
For config:
BrickletCANV2
@
GetErrorLEDConfig
[] → config¶Returns: |
|
---|
Returns the configuration as set by SetErrorLEDConfig[]
.
The following constants are available for this function:
For config:
BrickletCANV2
@
GetSPITFPErrorCount
[out errorCountAckChecksum, out errorCountMessageChecksum, out errorCountFrame, out errorCountOverflow] → Null¶Output Parameters: |
|
---|
Returns the error count for the communication between Brick and Bricklet.
The errors are divided into
The errors counts are for errors that occur on the Bricklet side. All Bricks have a similar function that returns the errors on the Brick side.
BrickletCANV2
@
SetStatusLEDConfig
[config] → Null¶Parameters: |
|
---|
Sets the status LED configuration. By default the LED shows communication traffic between Brick and Bricklet, it flickers once for every 10 received data packets.
You can also turn the LED permanently on/off or show a heartbeat.
If the Bricklet is in bootloader mode, the LED is will show heartbeat by default.
The following constants are available for this function:
For config:
BrickletCANV2
@
GetStatusLEDConfig
[] → config¶Returns: |
|
---|
Returns the configuration as set by SetStatusLEDConfig[]
The following constants are available for this function:
For config:
BrickletCANV2
@
GetChipTemperature
[] → temperature¶Returns: |
|
---|
Returns the temperature as measured inside the microcontroller. The value returned is not the ambient temperature!
The temperature is only proportional to the real temperature and it has bad accuracy. Practically it is only useful as an indicator for temperature changes.
BrickletCANV2
@
Reset
[] → Null¶Calling this function will reset the Bricklet. All configurations will be lost.
After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!
BrickletCANV2
@
GetIdentity
[out uid, out connectedUid, out position, out {hardwareVersion1, hardwareVersion2, hardwareVersion3}, out {firmwareVersion1, firmwareVersion2, firmwareVersion3}, out deviceIdentifier] → Null¶Output Parameters: |
|
---|
Returns the UID, the UID where the Bricklet is connected to, the position, the hardware and firmware version as well as the device identifier.
The position can be 'a', 'b', 'c', 'd', 'e', 'f', 'g' or 'h' (Bricklet Port). A Bricklet connected to an Isolator Bricklet is always at position 'z'.
The device identifier numbers can be found here. There is also a constant for the device identifier of this Bricklet.
BrickletCANV2
@
SetFrameReadCallbackConfiguration
[enabled] → Null¶Parameters: |
|
---|
Enables and disables the FrameReadCallback
callback.
By default the callback is disabled. Enabling this callback will disable the FrameReadableCallback
callback.
BrickletCANV2
@
GetFrameReadCallbackConfiguration
[] → enabled¶Returns: |
|
---|
Returns true if the FrameReadCallback
callback is enabled, false otherwise.
BrickletCANV2
@
SetFrameReadableCallbackConfiguration
[enabled] → Null¶Parameters: |
|
---|
Enables and disables the FrameReadableCallback
callback.
By default the callback is disabled. Enabling this callback will disable the FrameReadCallback
callback.
New in version 2.0.3 (Plugin).
BrickletCANV2
@
GetFrameReadableCallbackConfiguration
[] → enabled¶Returns: |
|
---|
Returns true if the FrameReadableCallback
callback is enabled, false otherwise.
New in version 2.0.3 (Plugin).
BrickletCANV2
@
SetErrorOccurredCallbackConfiguration
[enabled] → Null¶Parameters: |
|
---|
Enables and disables the ErrorOccurredCallback
callback.
By default the callback is disabled.
New in version 2.0.3 (Plugin).
BrickletCANV2
@
GetErrorOccurredCallbackConfiguration
[] → enabled¶Returns: |
|
---|
Returns true if the ErrorOccurredCallback
callback is enabled, false otherwise.
New in version 2.0.3 (Plugin).
Callbacks can be registered to receive time critical or recurring data from the device. The registration is done by assigning a function to a callback property of the device object:
MyCallback[sender_,value_]:=Print["Value: "<>ToString[value]] AddEventHandler[canV2@ExampleCallback,MyCallback]
For further information about event handling using .NET/Link see the corresponding Mathematica .NET/Link documentation.
The available callback property and their type of parameters are described below.
Note
Using callbacks for recurring events is always preferred compared to using getters. It will use less USB bandwidth and the latency will be a lot better, since there is no round trip time.
BrickletCANV2
@
FrameReadCallback
[sender, frameType, identifier, {data1, data2, ...}]¶Callback Parameters: |
|
---|
This callback is triggered if a data or remote frame was received by the CAN transceiver.
The identifier
return value follows the identifier format described for
WriteFrame[]
.
For details on the data
return value see ReadFrame[]
.
A configurable read filter can be used to define which frames should be
received by the CAN transceiver and put into the read queue (see
SetReadFilterConfiguration[]
).
To enable this callback, use SetFrameReadCallbackConfiguration[]
.
Note
If reconstructing the value fails, the callback is triggered with Null for data.
The following constants are available for this function:
For frameType:
BrickletCANV2
@
FrameReadableCallback
[sender]¶Callback Parameters: |
|
---|
This callback is triggered if a data or remote frame was received by the CAN
transceiver. The received frame can be read with ReadFrame[]
.
If additional frames are received, but ReadFrame[]
was not called yet, the callback
will not trigger again.
A configurable read filter can be used to define which frames should be
received by the CAN transceiver and put into the read queue (see
SetReadFilterConfiguration[]
).
To enable this callback, use SetFrameReadableCallbackConfiguration[]
.
New in version 2.0.3 (Plugin).
BrickletCANV2
@
ErrorOccurredCallback
[sender]¶Callback Parameters: |
|
---|
This callback is triggered if any error occurred while writing, reading or transmitting CAN frames.
The callback is only triggered once until GetErrorLog[]
is called. That function will return
details abount the error(s) occurred.
To enable this callback, use SetErrorOccurredCallbackConfiguration[]
.
New in version 2.0.3 (Plugin).
Virtual functions don't communicate with the device itself, but operate only on the API bindings device object. They can be called without the corresponding IP Connection object being connected.
BrickletCANV2
@
GetAPIVersion
[] → {apiVersion1, apiVersion2, apiVersion3}¶Output Parameters: |
|
---|
Returns the version of the API definition implemented by this API bindings. This is neither the release version of this API bindings nor does it tell you anything about the represented Brick or Bricklet.
BrickletCANV2
@
GetResponseExpected
[functionId] → responseExpected¶Parameters: |
|
---|---|
Returns: |
|
Returns the response expected flag for the function specified by the function ID parameter. It is true if the function is expected to send a response, false otherwise.
For getter functions this is enabled by default and cannot be disabled,
because those functions will always send a response. For callback configuration
functions it is enabled by default too, but can be disabled by
SetResponseExpected[]
. For setter functions it is disabled by default
and can be enabled.
Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is sent and errors are silently ignored, because they cannot be detected.
The following constants are available for this function:
For functionId:
BrickletCANV2
@
SetResponseExpected
[functionId, responseExpected] → Null¶Parameters: |
|
---|
Changes the response expected flag of the function specified by the function ID parameter. This flag can only be changed for setter (default value: false) and callback configuration functions (default value: true). For getter functions it is always enabled.
Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is sent and errors are silently ignored, because they cannot be detected.
The following constants are available for this function:
For functionId:
BrickletCANV2
@
SetResponseExpectedAll
[responseExpected] → Null¶Parameters: |
|
---|
Changes the response expected flag for all setter and callback configuration functions of this device at once.
Internal functions are used for maintenance tasks such as flashing a new firmware of changing the UID of a Bricklet. These task should be performed using Brick Viewer instead of using the internal functions directly.
BrickletCANV2
@
SetBootloaderMode
[mode] → status¶Parameters: |
|
---|---|
Returns: |
|
Sets the bootloader mode and returns the status after the requested mode change was instigated.
You can change from bootloader mode to firmware mode and vice versa. A change from bootloader mode to firmware mode will only take place if the entry function, device identifier and CRC are present and correct.
This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.
The following constants are available for this function:
For mode:
For status:
BrickletCANV2
@
GetBootloaderMode
[] → mode¶Returns: |
|
---|
Returns the current bootloader mode, see SetBootloaderMode[]
.
The following constants are available for this function:
For mode:
BrickletCANV2
@
SetWriteFirmwarePointer
[pointer] → Null¶Parameters: |
|
---|
Sets the firmware pointer for WriteFirmware[]
. The pointer has
to be increased by chunks of size 64. The data is written to flash
every 4 chunks (which equals to one page of size 256).
This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.
BrickletCANV2
@
WriteFirmware
[{data1, data2, ..., data64}] → status¶Parameters: |
|
---|---|
Returns: |
|
Writes 64 Bytes of firmware at the position as written by
SetWriteFirmwarePointer[]
before. The firmware is written
to flash every 4 chunks.
You can only write firmware in bootloader mode.
This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.
BrickletCANV2
@
WriteUID
[uid] → Null¶Parameters: |
|
---|
Writes a new UID into flash. If you want to set a new UID you have to decode the Base58 encoded UID string into an integer first.
We recommend that you use Brick Viewer to change the UID.
BrickletCANV2
@
ReadUID
[] → uid¶Returns: |
|
---|
Returns the current UID as an integer. Encode as Base58 to get the usual string version.
BrickletCANV2
`
DEVICEUIDENTIFIER
¶This constant is used to identify a CAN Bricklet 2.0.
The GetIdentity[]
function and the
IPConnection@EnumerateCallback
callback of the IP Connection have a deviceIdentifier
parameter to specify
the Brick's or Bricklet's type.
BrickletCANV2
`
DEVICEDISPLAYNAME
¶This constant represents the human readable name of a CAN Bricklet 2.0.