Documentation

Disable CAN Channel

This input port is available whenever the Show Input Port to Disable the CAN Channel checkbox in the block mask is selected. Use this port to check whether the channel is enabled to interact on the bus or not.

Providing a logical "1" to this input signal stops the CAN channel from interacting on the bus. This channel will stop transmission and reception of new data with the next sample step. The transmit and receive buffer will be flushed.

This functionality can be used to simulate a channel disconnecting from the bus. Among other things, this means that the channel stops setting ACK bits. However, all the status indicators or counter values will remain until the channel is enabled again.

The channel will always start in an enabled state.

This block comes with several outputs by default. Enabling the expert mode will provide further outputs in addition to the default ones. Refer to the Enable Expert Mode parameter below for additional information.

Bus Load

CAN bus load in percentage as cyclically reported by the hardware every 500 ms. When starting a new transmission there will be a timeout of up to two cycles (1 s) to collect sufficient data until the busload is reported correctly. This will happen on startup or generally when a channel is being disconnected from or connected to the bus.

When the bus is overloaded or a cable is disconnected the signal may fluctuate between 0% and 100%.

Bus-Off Status

Indicates if the CAN controller is in bus off mode as described within the CAN specification. This is set if the associated CAN Transmit Error Counter reaches the bus off limit of 255 errors.

This state will be automatically recovered by the controller as soon as it is detected.

Error Frames

Number of error frames received since simulation start. This counter will only reset on a model restart.

Transmit Buffer Overrun

Indicates an overrun on the transmit buffer of this channel. This shows if there was a potential data loss in the output signal flow. The buffer may overflow if the traffic on the CAN Write block is too large for the configured sample rate. The size of this buffer is 16383 messages.

Receive Buffer Overrun

Indicates an overrun on the receive buffer of this channel. This shows if there was a potential data loss in the output signal flow. The buffer is only used if the CAN Read block is in FIFO mode. It may overflow if the bus-load is too high or because the receive buffer is not read out by a CAN Read block using a fast enough sample rate. The size of this buffer is 16383 messages.

Bus-Warning Limit

Indicates if the CAN controller has reached the bus warning limit as described within the CAN specification. This is set if either the associated CAN Receive Error Counter or the CAN Transmit Error Counter reaches the warning limit of 96 errors.

Bus-Error Passive

Indicates if the CAN controller is in error passive mode as described within the CAN specification. This is set if either the associated CAN Receive Error Counter or the CAN Transmit Error Counter reaches the passive limit of 127 errors.

Timestamp

Outputs the timestamp of when the status data was retrieved on the bus in seconds (s) in relation to the model start.

Aborted Frames

Number of aborted transmission frames since simulation start. This counter will only reset at model restart. A transmitting frame will be aborted if the default timeout of 1 ms is exceeded while the frame is in the transmit buffer.

Receive Error Counter

Number of receive errors currently on this channel since simulation start. This counter is increased by 1 if an error is detected during reception. If no other CAN node detected this error, the counter is increased by 8. Each successful reception decreases this counter by 1.

Transmit Error Counter

Number of transmit errors currently on this channel since simulation start. This counter is increased by 8 if an error is detected during transmission of this channel. Each successful transmission decreases this counter by 1.

Bit Count

Number of bits on the CAN bus since simulation start. This counter will only reset on a model restart.

Module ID

This ID defines the link to the corresponding Setup block

Channel Number

Selects the CAN channel with which this driver block communicates.

Enable Expert Mode

If this is enabled, the following output ports are available in addition to the default ones:

• Timestamp

• Aborted Frames

• Receive Error Counter

• Transmit Error Counter

• Bit Count

Show Input Port to Disable the CAN Channel

Enables an input port that can be used to disable the associated channel.

Sample Time

Defines the base sample time at which this driver block gets its sample hit. This parameter can also be set to -1 for inherited sample time. The units are in seconds.