EP80579 Datasheet, PDF (1581/1916 Pages) Intel Corporation – Intel® EP80579 Integrated Processor Product Line

Intel^® EP80579 Integrated Processor
Note:
39.5.3
39.5.3.1
39.5.3.2
The errors are always detected and registered in the interrupt status register. The
interrupt enable register determines whether or not it gets propagated. For more
information please refer to “Offset 00000000h: Int_status - Interrupt Status Register”
and “Offset 00000004h: Int_Ebl - Interrupt Enable Register”
Send/Receive Procedure
Send Procedure
Use the following procedure to send a message:
1. Write a message into one of the transmit message holding buffers. An empty buffer
is indicated by a TxReq that equals zero.
2. Request transmission by setting the respective TxReq flag to ‘1’.
3. The TxReq flag remains set as long as the message transmit request is pending.
The content of the message buffer must not change while the TxReq flag is set.
4. The internal message priority arbiter selects the message according to the chosen
arbitration scheme.
5. Once the message is transmitted, the TXReq flag is set to zero and the TxMsg
interrupt status is asserted.
A message can be removed from a transmit holding buffer by setting the TxAbort flag.
Use the following procedure to remove the contents of a particular TxMessage buffer:
1. Set TxAbort to ‘1’ to request the message removal.
2. The TxAbort flag remains set as long as the message abort request is pending. The
flag is cleared when either the message wins arbitration (TxMsg interrupt active) or
the message is removed (TxMsg interrupt inactive).
Receive Procedures
The CAN unit supports 16 individual receive message buffers. Each one has its own
message filter mask. Automatic reply to RTR messages is supported.
If a message is accepted in a receive buffer, its MsgAv flag is set. The message remains
valid as long as MsgAv flag is set. The host CPU has to reset the MsgAv flag to enable
receipt of a new message.
Figure 39-8. Receive Message Handler
RxMessage 0
1
RxMessage 1
2
RxMessage 2
3
16
RxMessage 15
RxMessage
Handler
iniCAN
CANbus
CANmodule -III
August 2009
Order Number: 320066-003US
Intel^® EP80579 Integrated Processor Product Line Datasheet
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