CAN CC/FD/XL (Controller Area Network: Classical CAN, CAN FD, CAN XL)
CAN (Controller Area Network) is a field bus from Bosch for automotive and industrial use. The decode takes one digital channel, labelled RXD. Connect it to the RXD output of the transceiver. Frame types include Data, Remote, Error, and Overload.
| Generation | Data length | CRC | Data-phase rate |
|---|---|---|---|
| CAN CC (Classical CAN, 2.0B) | 0–8 bytes | CRC15 | – |
| CAN FD | up to 64 bytes | CRC17 / CRC21 (ISO or non-ISO) | 250 Kbps–10 Mbps |
| CAN XL | up to 2048 bytes | PCRC (13 bit) and FCRC (32 bit) | 1–20 Mbps |
CAN XL decoding is off by default. With it off, the decode and the report are the same as for CAN and CAN FD only. Check Enable CAN XL, or set Frame Format to CAN XL, to decode CAN XL frames.
A wrong Arbitration or Data phase rate, or the wrong signal polarity, fails decode. For channel-prefix differences, see Settings.
Decode Settings
| Setting | What it does | Default |
|---|---|---|
| Invert | Inverts the input signal. Check it when the signal has the reverse polarity. | Cleared |
| Frame Format | Selects which frame formats are decoded. Auto: reads the format from each frame. CAN: a recessive FDF bit is a Form Error. CAN FD: a recessive res bit is a Form Error. CAN XL: decodes CAN, CAN FD and CAN XL frames. |
Auto |
| Enable CAN XL | Decodes CAN XL frames and adds the SDT and VCID report columns. Available when Frame Format is Auto. Checked and locked when Frame Format is CAN XL. Locked off when Frame Format is CAN or CAN FD. | Cleared |
| ISO-CRC / Non ISO-CRC | CRC rule for CAN FD frames. Disabled when Frame Format is CAN. | ISO-CRC |
| Show scale in the waveform | Shows the bit scale on the waveform. Enabled only when Frame Format is CAN. | Cleared |
| Arbitration | Arbitration-phase rate in Kbps (5–1000), or Auto. | Auto |
| Data phase | CAN FD data-phase rate in Kbps (250–10000), or Auto. Disabled when Frame Format is CAN. | 1000 |
| XL data phase | CAN XL data-phase rate in Kbps (1000–20000). Enabled when CAN XL is enabled. | 8000 |
| Sample point | Sampling position inside a data-phase bit, 70–80 %. One value for Data phase and one for XL data phase. | 80 % |
| Data Filter | Shows only frames whose Data is within the given length (8–60 bytes); longer Data is omitted. When checked, the length field is enabled. | Cleared (show all); length 8 |
| Report Data | Number of Data bytes per report row (8-byte / 16-byte / 32-byte). A longer payload continues on the following rows. | 8-byte |
Report
| Column | Content |
|---|---|
| Frame Type | Frame kind. Prefix FD for CAN FD and XL for CAN XL: Std Data, Ext Data, Std Remote, Ext Remote, FD Std Data, XL Std Data, Error, Overload. |
| ID(h) | Identifier. |
| SDT | CAN XL only (Enable CAN XL checked): SDU type. |
| VCID | CAN XL only (Enable CAN XL checked): virtual CAN network ID. |
| DLC | Number of data bytes. |
| Data | Data bytes. |
| CRC(h) | CRC15 (CAN), CRC17 / CRC21 (CAN FD), FCRC (CAN XL). |
| ASCII(Data) | Data as ASCII. |
| Information | First row: Data Rate, the arbitration-phase rate. Errors. At the end of the report, one row each for FD Data Rate and XL Data Rate, the data-phase rates; a row appears only when the capture has frames of that generation. Below them are summary rows, one item per row: N error events (a run of bad frames or error rows with no good frame between counts once), N good frames, N Active Error Frame and N Passive Error Frame, and N frames not counted (frames with an ACK error, or cut off by the end of the capture). The last three appear only when the count is not zero. The summary counts only what is visible on the bus; it does not estimate any node's internal error counters. |
| Frame Duration | Time from the start to the end of the frame. |
With Enable CAN XL cleared the report has the first set of columns without SDT and VCID.
The other CAN XL fields are marked in the waveform area:
| Field | Content |
|---|---|
| XLF, resXL | CAN XL format bit and reserved bit |
| ADS, DAS | Phase-switch sequences before and after the data phase |
| SDT, SEC | SDU type, simple extended content |
| DLC, SBC | Data length code, stuff-bit count |
| PCRC, FCRC | 13-bit CRC of the header, 32-bit CRC of the frame |
| VCID, AF | Virtual CAN network ID, acceptance field |
| FCP | Frame check pattern |
Errors shown in the Information column:
| Text | Meaning |
|---|---|
| CRC Error, PCRC Error | The CRC does not match. In CAN XL, a wrong FCP counts as a CRC Error. |
| Form Error | A fixed-format bit has the wrong value, including a wrong fixed stuff bit. |
| ACK Error | The ACK slot is recessive. |
| Stuff Error | Six identical bits in the stuffed part of a frame. |
| Bit Error | A transmitted bit and the bus level differ. |
| Active Error Frame, Passive Error Frame, Error Delimiter | Error signalling after a frame error. Consecutive errors of one type are folded into one row with a count. |
| Overload Frame | Overload signalling. |
| Break by Error Frame, Break by Unknown | The frame ended before its end of frame. |
| Incomplete frame (capture ended) | The capture ended inside the frame. |
Result
Connect the RXD output of the transceiver.
