CANB_W - Wishbone CAN Controller with Direct Addressing
Figure 1. CANB_W - Wishbone CAN Controller with Direct Addressing.
The CAN Controller component (CANB_W) is a stand-alone, Wishbone-compliant controller, for a Controller Area Network conforming to the CAN 2.0B specification. It provides an interface between a processor and a CAN bus. The Controller implements the BOSCH CAN 2.0B Data Link Layer Protocol.
The CAN Controller is compatible with the Philips SJA1000 working in its PeliCAN mode.
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Features at-a-glance
- Supports Standard Frame Format (11-bit identifier) and Extended Frame Format
(29-bit identifier)
- 64-byte Receive FIFO with 13-byte window (Receive Buffer) pointing to first message to be read from FIFO
- Data Overrun control
- Received Message Counter
- Receive Buffer Start Address Register reflecting the current position where the first byte of the received message is stored
- 13-byte Transmit Buffer
- Compound, programmable Acceptance Filter
- Single and Dual Acceptance Filter mode
- 4-byte code
- 4-byte mask
- Access to bit-position in message identifier where arbitration lost occurred.
- Error Confinement
- Error Receive and Transmit Counters with read and write access
- Programmable Error Warning Limit
- Access to last error code that informs about type of error that occurred and error position in bit-stream.
- Listen Only Mode – CAN Controller has no influence on CAN bus, no active error flags, no overload flags and no acknowledgments can be sent, but it can receive messages.
- Self Test Mode with Self Reception Request – full node test possibility without any other active node; message acknowledgement is not required and transmission with simultaneous reception possible.
- Single Shot Transmission – no re-transmission required
- Sleep Mode with reduced power consumption.
- Programmable Bit Timing Logic
- Programmable Bit Rate
- Programmable ClockOut Period
- Programmable bit-period length – TSeg1, TSeg2
- Programmable Synchronization Jump Width
- Single- and triple- sampling modes.
- Output Modes
- Normal mode
- ClockOut mode
- Biphase mode
- Test mode
- Receive interrupt output enable (in normal mode).
- Input Modes
- Normal mode
- Test mode.
- Compound and Flexible Interrupt Structure.
- Wishbone-compliant
Availability
From an OpenBus System document, the CAN Controller (B) component can be found in the Peripherals region of the OpenBus Palette panel.
From a schematic document, the CANB_W component can be found in the FPGA Peripherals (Wishbone) integrated library (FPGA Peripherals (Wishbone).IntLib), located in the \Library\Fpga folder of the installation.
Designing with the CANB_W
Use the following links to explore use of the CANB_W in more detail: