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

NAME

canconfigconfigure CAN network interface parameters

SYNOPSIS

canconfig -a

canconfig canif

canconfig can command [args ...]

DESCRIPTION

The canconfig utility is used to configure CAN network interface parameters 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 majority 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.
April 15, 2017 NetBSD 8.1