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GG System Software GbR
Software Engineering
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GG System Software GbR
Software Engineering
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CAN ISO TRANSPORT PROTOCOL (ISO 15765-2)
Günter Gebhardt, M. Systems Eng.
g.gebhardt@gg-sw-systems.de
www.gg-sw-systems.de
1. June 2022
1. Overall N_PDU Format
+------+-------+--------+
| N_AI | N_PCI | N_Data |
+------+-------+--------+
N_AI - Address Information
N_PCI - Protocol Control Information
N_Data - Data field
N_AI consist of or depends on the following elements
Mtype - Message Type (diagnostics, remote diagnostics)
N_TAtype - Target Address Type (physical, functional)
N_TA - Target Address (0x00-0xFF)
N_SA - Source Address (0x00-0xFF)
N_AE - Address Extension (0x00-0xFF, Mtype 'remote diagnostics')
CAN/CANFD Frame usage is defined by the following parameters:
CAN_DL (n) - Physical length of CAN/CANFD frame data in bytes.
TX_DL - Transmit data link layer data length (limits CAN_DL, 8 - 64)
1.1. Addressing Formats
1.1.1. Normal Addressing, physical/functional Target Address, 11 Bit ID
Used when Mtype is 'diagnostics'.
+-----------+---------+--------+ +--------+
| 11 Bit ID | Byte 0 | Byte 1 | ... | Byte n |
+-----------+---------+--------+ +--------+
|<--N_AI--->|<-N_PCI->|<-------N_Data-------->|
1.1.2. Normal fixed Addressing, physical Target Address, 29 Bit ID
Used when Mtype is 'diagnostics'.
+-----------+---------+--------+ +--------+
| 29 Bit ID | Byte 0 | Byte 1 | ... | Byte n |
+-----------+---------+--------+ +--------+
|<--N_AI--->|<-N_PCI->|<-------N_Data-------->|
+--------+ +--------+--------+ +-------+-------+ +-------+
| Bit 28 | ... | Bit 16 | Bit 15 | ... | Bit 8 | Bit 7 | ... | Bit 0 |
+--------+ +--------+--------+ +-------+-------+ +-------+
|<--------0x18DA------->|<--------N_TA-------->|<-------N_SA-------->|
|<-------------------------------N_AI------------------------------->|
1.1.4. Normal fixed Addressing, functional Target Address, 29 Bit ID
Used when Mtype is 'diagnostics'.
+-----------+---------+--------+ +--------+
| 29 Bit ID | Byte 0 | Byte 1 | ... | Byte n |
+-----------+---------+--------+ +--------+
|<--N_AI--->|<-N_PCI->|<-------N_Data-------->|
+--------+ +--------+--------+ +-------+-------+ +-------+
| Bit 28 | ... | Bit 16 | Bit 15 | ... | Bit 8 | Bit 7 | ... | Bit 0 |
+--------+ +--------+--------+ +-------+-------+ +-------+
|<--------0x18DB------->|<--------N_TA-------->|<-------N_SA-------->|
|<-------------------------------N_AI------------------------------->|
1.1.5. Extended Addressing, physical/functional Target Address, 11 Bit ID
Used when Mtype is 'diagnostics'.
+-----------------------+--------+---------+--------+ +--------+
| 11 Bit ID | Byte 0 | Byte 1 | Byte 2 | ... | Byte n |
+-----------------------+--------+---------+--------+ +--------+
|<--N_AI except N_TA--->|<-N_TA->|<-N_PCI->|<-------N_Data-------->|
1.1.6. Mixed Addressing, physical Target Address, 29 Bit ID
Used when Mtype is 'remote diagnostics'.
+--------------------+--------+---------+--------+ +--------+
| 29 Bit ID | Byte 0 | Byte 1 | Byte 2 | ... | Byte n |
+--------------------+--------+---------+--------+ +--------+
|<-N_AI except N_AE->|<-N_AE->|<-N_PCI->|<-------N_Data-------->|
|<-----------N_AI------------>|
+--------+ +--------+--------+ +-------+-------+ +-------+
| Bit 28 | ... | Bit 16 | Bit 15 | ... | Bit 8 | Bit 7 | ... | Bit 0 |
+--------+ +--------+--------+ +-------+-------+ +-------+
|<--------0x18CE------->|<--------N_TA-------->|<-------N_SA-------->|
|<--------------------------N_AI except N_AE------------------------>|
1.1.7. Mixed Addressing, functional Target Address, 29 Bit ID
Used when Mtype is 'remote diagnostics'.
+--------------------+--------+---------+--------+ +--------+
| 29 Bit ID | Byte 0 | Byte 1 | Byte 2 | ... | Byte n |
+--------------------+--------+---------+--------+ +--------+
|<-N_AI except N_AE->|<-N_AE->|<-N_PCI->|<-------N_Data-------->|
|<-----------N_AI------------>|
+--------+ +--------+--------+ +-------+-------+ +-------+
| Bit 28 | ... | Bit 16 | Bit 15 | ... | Bit 8 | Bit 7 | ... | Bit 0 |
+--------+ +--------+--------+ +-------+-------+ +-------+
|<--------0x18CD------->|<--------N_TA-------->|<-------N_SA-------->|
|<--------------------------N_AI except N_AE------------------------>|
1.1.8. Mixed Addressing, physical/functional Target Address, 11 Bit ID
Used when Mtype is 'remote diagnostics'.
+--------------------+--------+---------+--------+ +--------+
| 11 Bit ID | Byte 0 | Byte 1 | Byte 2 | ... | Byte n |
+--------------------+--------+---------+--------+ +--------+
|<-N_AI except N_AE->|<-N_AE->|<-N_PCI->|<-------N_Data-------->|
|<-----------N_AI------------>|
2. N_PCI Types
+-------------------------+
| Byte 0 |
| 7 6 5 4 | 3 2 1 0 |
| 1st Nibble | 2nd Nibble |
| FT | |
+-------------------------+
|<---------N_PCI--------->|
1st Nibble - Defines the frame type (FT):
0x0 : SF-I (Single Frame ISO compliant)
0x1 : FF-I (First Frame ISO compliant)
0x2 : CF (Consecutive Frame ISO compliant)
0x3 : FC (Flow control frame)
2nd Nibble - Content depends on the frame type determined by 1st Nibble
3. Frame Types
3.1. Single Frame (CAN_DL <= 8)
+-------------------------+--------+ +--------+
| Byte 0 | Byte 1 | | Byte n |
| 7 6 5 4 | 3 2 1 0 | | | |
| 1st Nibble | 2nd Nibble | | ... | |
| 0x0 | DL | | | |
+-------------------------+--------+ +--------+
|<---------N_PCI--------->|<-------N_Data-------->|
DL - Data Length (0x1-0x7)
3.2. Single Frame (CAN_DL > 8)
+-------------------------+--------+--------+ +--------+
| Byte 0 | Byte 1 | Byte 2 | | Byte n |
| 7 6 5 4 | 3 2 1 0 | | | | |
| 1st Nibble | 2nd Nibble | | | ... | |
| 0x0 | 0x0 | DL | | | |
+-------------------------+--------+--------+ +--------+
|<--------------N_PCI------------->|<-------N_Data-------->|
DL - Data Length (0x1-(TX_DL - N_AE.size - N_PCI.size))
TX_DL - Size of the N_PDU i.e. the CAN frame.
3.3. First Frame (DL <= 4095)
+-------------------------+--------+--------+ +--------+
| Byte 0 | Byte 1 | Byte 2 | | Byte n |
| 7 6 5 4 | 3 2 1 0 | | | | |
| 1st Nibble | 2nd Nibble | | | ... | |
| 0x1 | DL MSB | DL LSB | | | |
+-------------------------+--------+--------+ +--------+
|<--------------N_PCI------------->|<-------N_Data-------->|
DL MSB - Holds the most significant bits of DL.
DL LSB - Holds the least significant bits of DL.
DL - Data Length of the whole message (0x001-0xFFF)
3.4. First Frame (DL > 4095)
+-------------------------+--------+--------+--------+--------+--------+ +--------+
| Byte 0 | Byte 1 | Byte 2 | Byte 3 | Byte 4 | Byte 5 | | Byte n |
| 7 6 5 4 | 3 2 1 0 | | | | | | | |
| 1st Nibble | 2nd Nibble | | | | | | ... | |
| 0x1 | 0x0 | 0x00 | | | | | | |
+-------------------------+--------+--------+--------+--------+--------+ +--------+
|<-------------N_PCI-------------->|<-----------DL----------->|<-------N_Data-------->|
DL - Data Length of the whole message in big endian format (0x00000001-0xFFFFFFFF)
3.5. Consecutive Frame
+-------------------------+--------+ +--------+
| Byte 0 | Byte 1 | | Byte n |
| 7 6 5 4 | 3 2 1 0 | | | |
| 1st Nibble | 2nd Nibble | | ... | |
| 0x2 | SN | | | |
+-------------------------+--------+ +--------+
|<--------N_PCI---------->|<-------N_Data-------->|
SN - Sequence Number (0x1-0xF)
3.6. Flow Control Frame
+-------------------------+--------+--------+
| Byte 0 | Byte 1 | Byte 2 |
| 7 6 5 4 | 3 2 1 0 | | |
| 1st Nibble | 2nd Nibble | | |
| 0x3 | FS | BS | STmin |
+-------------------------+--------+--------+
|<------------------N_PCI------------------>|
FS - Flow Status:
0x0: CTS, Clear To Send
0x1: WT, Wait
0x2: OVFLW, Overflow
BS - Block Size:
0x00 (unacknowleged/acknowledged without retry): Unlimited block size
0x01-0xFF (unacknowledged): Number of CFs in one block
0x01-0x10 (acknowledged with retry): Number of CFs in one block
STmin - Minimum Separation Time
0x00-0x7F: ST in number of milliseconds
0xF1-0xF9: ST in number of microseconds starting with 100us and a step width of 100us