TC1796
Peripheral Units (Vol. 2 of 2)
Controller Area Network (MultiCAN) Controller
User’s Manual 22-40 V2.0, 2007-07
MultiCAN, V2.0
22.3.9 Message Postprocessing
After a message object has successfully received or transmitted a frame, the CPU can
be notified to perform a postprocessing on the message object. The postprocessing of
the MultiCAN module consists of two elements:
1. Message interrupts to trigger postprocessing.
2. Message pending registers to collect pending message interrupts into a common
structure for postprocessing.
22.3.9.1 Message Object Interrupts
When the storage of a received frame into a message object or the successful
transmission of a frame is completed, a message interrupt can be issued. For each
message object, a transmit and a receive interrupt can be generated and routed to one
of the sixteen CAN interrupt output lines (see Figure 22-17). A receive interrupt occurs
also after a frame storage event that has been induced by a FIFO or a gateway action.
The status bits TXPND and RXPND in the Message Object n Status Register are always
set after a successful transmission/reception, whether or not the respective message
interrupt is enabled.
A third FIFO full interrupt condition of a message object is provided. If bit field
MOFCRn.OVIE (Overflow Interrupt Enable) is set, the FIFO full interrupt be activated
depending on the actual message object type.
In case of a Receive FIFO Base Object (MOFCRn.MMC = 0001
B
), the FIFO full interrupt
is routed to the interrupt output line INT_Om as defined by the transmit interrupt node
pointer MOIPRn.TXINP.
In case of a Transmit FIFO Base Object (MOFCRn.MMC = 0010
B
), the FIFO full interrupt
becomes routed to the interrupt output line INT_Om as defined by the receive interrupt
node pointer MOIPRn.RXINP.
See also “Interrupt Control” on Page 22-210 for further processing of the message
object interrupts.
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