11.2.1 CAN Controller Interface Signals

This section describes the CAN bus interfaces. The following table lists the external interface signals that connects the SmartFusion 2 device to an off-chip CAN transceiver.

Table 11-1. CAN Bus Interface
Signal Name Direction Description
RX Input CAN bus receive signal. This signal connects to the receiver bus of the external driver.
TX Output CAN bus transmit signal. This signal connects to the external driver.
TX_EN_N Output External driver enable control signal

This signal is used to enable or disable the external CAN transceiver.

TX_EN_N is asserted when the CAN controller is stopped or if the CAN state is bus-off (shut down completely)

When enabled, by default the CAN ports are configured to connect to SmartFusion 2 Multi-Standard I/Os (MSIOs). CAN signals are also configured to interface with the FPGA fabric and the MSS General Purpose Inputs/Outputs (GPIOs). The CAN configurator within Libero SoC allows selection from among the fabric, MSIOs, and GPIOs.

Important: The MSIOs allocated to the CAN instance are shared with other MSS peripherals. These shared I/Os are available to connect to the MSS GPIOs and other peripherals when the CAN instance is disabled or if the CAN instance ports are only connected to the FPGA fabric. For more details, see MSS CAN Configurator User Guide.