canconfig(8) - NetBSD Manual Pages

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CANCONFIG(8)            NetBSD System Manager's Manual            CANCONFIG(8)


NAME

     canconfig -- configure CAN network interface parameters


SYNOPSIS

     canconfig -a
     canconfig canif
     canconfig can command [args ...]


DESCRIPTION

     The canconfig utility is used to configure CAN network interface parame-
     ters and retrieve CAN network interface parameters and status from the
     kernel.

   Timing
     The base time unit used to define the network bit rate is the time quanta
     (tq), its value is defined by the input clock frequency and the prescaler
     value as (1/ freq * prescaler).

     The network bit time is split in 4 segments:
           sync_seg    fixed to 1 tq
           prop_seg
           phase_seg1
           phase_seg2
     The network bit time is (1 + prop_seg + phase_seg1 + phase_seg2), in tq.
     The sample point is between phase_seg1 and phase_seg2.

     The receiver hardware is allowed to shorten prop_seg or phase_seg2 to
     resynchronize with the sender.  The swj (Synchronisation Jump Width)
     parameter defines by how much the hardware can shorten these segments.

     Some hardware can use 3 sample points instead of one, and keep the major-
     ity as the final value.

   Options
     The options are as follows:

     -a      Display the status of all CAN devices present on the system.
             This flag is mutually exclusive with all other sub-commands.

     All other operations require that a CAN interface be specified.  If a CAN
     interface is specified with no sub-commands, the status of that interface
     is displayed.

     The following sub-commands are available:

     up      Start network operations on the interface.  Requires that all
             timing parameters have been set.

     down    Stop network operations on the interface.

     brp value
             Set the value of the baud rate prescaler.

     prop_seg value
             Set the number of tq for the propagation segment.

     phase_seg1 value
             Set the number of tq for the phase segment 1.

     phase_seg2 value
             Set the number of tq for the phase segment 2.

     sjw value
             Set the number of tq for the Synchronisation Jump Width.

     3samples
             Enable triple-sampling.

     -3samples
             Disable triple-sampling.

     listenonly
             Enable listen-only mode.  In this mode the controller is passive,
             and doesn't send ACKs on the bus.

     -listenonly
             Disable listen-only mode.

     loopback
             Enable loopback mode.  In this mode, the controller doesn't
             expect ACK from the bus.

     -loopback
             Disable loopback mode.


SEE ALSO

     ifconfig.if(5), ifconfig(8)


HISTORY

     The canconfig utility first appeared in NetBSD 8.0.


AUTHORS

     This version of the canconfig utility was written by Manuel Bouyer.

NetBSD 10.1                     April 15, 2017                     NetBSD 10.1