AN2341

Interrupt sources and identification

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1.2.3

Message-specific interrupts

Message-specific interrupts are generated by each message object. They are individually

enabled by setting bit TXIE (for transmission) or RXIE (for reception), or both, in the CAN

message objects.

Message-specific interrupts are caused by:

●

Reception of a message (data frame or remote) into the corresponding message

object.

●

Successful transmission (data frame or remote) of the corresponding message object.

Bit ‘IntPnd’ in each message object indicates that the corresponding message object has

generated an interrupt request.

Note:

Refer to Section 2.1: Message-specific interrupts for further information on decoding

message-specific interrupts.

Identifying interrupt sources

The value of IntId code in the Interrupt register identifies the interrupt source; the Status

Interrupt has the highest priority. Among the message interrupts, the Message Object’s

interrupt priority decreases with increasing message number. A message interrupt is

cleared by clearing the Message Object’s IntPnd bit. The Status Interrupt is cleared by

reading the Status register.

●

IntId = 0000h: Indicates that no (or no more) interrupt/s is/are pending.

●

IntId = 0001h to 0020h: Indicate a Message-specific Reception or Transmission from

message object 1 to 32.

●

IntId = 8000h: Indicates that a Status Change Interrupt or an Error Interrupt is pending.