Specifications

5 CAN I/O Support for FIFO
5-34
Identifier selection mode — Defines how the identifier criterion entered in
the control above is treated. If you select Include, the identifier criterion is the
sum of all specified identifiers. If you select Exclude, the identifier criterion is
equal to all identifiers minus the specified identifiers.
You can use as many instances of this block in your model as needed. Usually,
you connect several instances in parallel to the output of the FIFO Read driver
block in order to filter out particular messages or events. For more information
on how to do this, see “Examples” on page 5-40.
FIFO Read XMT Level Driver Block
The FIFO Read XMT Level driver block is used to read the current number of
CAN messages stored in the transmit FIFO to be processed by the firmware.
The transmit FIFO can store up to 255 messages. If it is full and a FIFO write
driver block tries to add another messages to the transmit FIFO the passed
messages are lost. You can use this driver block to check for this condition and
take appropriate action. For example, you could stop the execution or wait for
a non-full transmit FIFO.
The block has a single output port of type double returning a scalar value
containing the current transmit FIFO level (number of messages to be
processed).
The dialog box of the block lets you define the following settings.
Board — Defines which physically present board is accessed to read the
current transmit FIFO level. For more information about the meaning of the
board number see the Setup driver block described above. If just one board is
present in the target system, board number 1 should be selected.