EP80579 Datasheet, PDF (1583/1916 Pages) Intel Corporation – Intel® EP80579 Integrated Processor Product Line

Intel^® EP80579 Integrated Processor
Table 39-3. CAN Higher Level Protocol (HLP) Bit Assignment
CANopen Identifier
10 9 8 7 6 5 4 3 2 1 0
Function Code
Node-ID
Identifier fields:
• Function Code: The function code for a TDPO1 message is 3h.
• Node-ID: The example uses 02h as the Node ID.
• IDE = ‘0’: CANopen uses the short format message.
• RTR = ‘0’:Identifies a regular message.
To accept this message, the acceptance filter settings would look like the following:
• AMR settings:
ID[28:18] = 0
ID[17:0] = all ones
IDE = 0
RTR = 0
DATA[63:56] = all ones
• ACR settings:
ID[28:18] = 182h
ID[17:0] = don't care
IDE = 0
RTR = 0
DATA[63:56] = don’t care
39.5.3.5
RTR Auto-Reply
The CAN unit supports fully automatic answering of RTR message requests. All 16
receive buffers support this feature. If an RTR message is accepted in a receive buffer,
where the RTRreply flag is set, then this buffer automatically replies to this message
with the content of this receive buffer. The RTRreply_pending flag is set when the RTR
message request is received. The flag is reset when the message was sent or when the
message buffer is disabled. To abort a pending RTRreply message, use the RTRabort
command.
39.5.3.6
RxBuffer Linking
Several receive buffers may be linked together to form a receive buffer array which
acts like a receiver FIFO.
The requirements are as follows:
• All buffers of the same array must have the same message filter setting (AMR and
ACR are identical).
• The last buffer of an array may not have its link flag set.
When a receive buffer already contains a message (MsgAv=’1’) and a new message
arrives for this buffer, then this message would be discarded (RxMsgLoss Interrupt). To
avoid this situation, several receive buffers can be linked together. When the CAN unit
receives a new message, the RxMessage handler searches for a valid receive buffer. If
August 2009
Order Number: 320066-003US
Intel^® EP80579 Integrated Processor Product Line Datasheet
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