Appendix A. The Extended CAN / SAE-J1939 Message Frame
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| Arbitration Field |
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| Control Field |
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| Data | CRC | Ack | EOF | ||||||||
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| Field | Field | Field |
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S |
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| Identifier | (11) bits |
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| S | I |
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| Identifier Extension | (18 Bits) |
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| R | R | R |
| DLC |
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1 | 2 |
| 3 | 4 | 5 | 6 |
| 7 | 8 |
| 9 | 1 | 1 | 1 | 2 | 3 | 4 |
| 5 | 6 | 7 |
| 8 | 9 | 1 | 1 | 1 | 1 |
| 1 | 1 | 1 | 1 | 1 | 1 |
| 2 | 3 | 4 | 8 bytes | 2 bytes |
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O |
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| 0 | 1 | R | D |
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| 0 | 1 | 2 | 3 |
| 4 | 5 | 6 | 7 | 8 | T | 1 | 0 |
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| 64 bits | 16 bits |
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F | Priority |
| R | D | PDU Format (PF) |
| S | E | PF |
| PDU Specific (PS) |
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| Source Address |
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| R |
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| (3 bits) |
| 1 | P |
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| (8 bits) |
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| Cont |
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| (8 Bits) |
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| (8 Bits) |
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1 | 2 | 3 |
| 4 | 5 | 6 | 7 |
| 8 | 9 |
| 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| 1 | 2 | 2 |
| 2 | 2 | 2 | 2 | 2 | 2 |
| 2 | 2 | 3 | 3 | 3 | 3 | 3 | 3 | 3 |
| 3 | 3 | 3 |
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| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
| 9 | 0 | 1 |
| 2 | 3 | 4 | 5 | 6 | 7 |
| 8 | 9 | 0 | 1 | 2 | 3 | 4 | 5 | 6 |
| 7 | 8 | 9 |
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The table above shows a comparison between the
The bold line separates the upper and lower parts of the table. The upper half of the table shows the CAN data frame labels and the lower part of the table contains the
The CAN extended frame is made up of 6 fields: Arbitration, Control, Data, CRC, ACK, EOF. The arbitration field is subdivided into two fields of 11 and 18 bit identifiers. CAN uses these fields to determine both identification and priority.
The
Priority | 3 bits with a value of 0 to 7 - with 0 having the highest priority. |
R1 | 1 bit. This bit is reserved by the SAE for future use and should be set to 0. |
DP Data Page | 1bit. Sets an auxiliary page of parameter groups. |
8 bit. One of the fields that makes up the Parameter Group Number. | |
8 bit. The second field the makes up the Parameter Group Number. |
Source Address 8 bit. The address of the sending/receiving node.
The fields above are required to send a message on the
An expanded view of the Arbitration field is shown on the following page.
1939STB4600 Manual | Appendix A |
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