devcan-flexcan

CAN driver for FlexCAN Controller

Syntax:

devcan-flexcan [options] ["can#"[,sysirq[,sysirq[,sysirq]]]]
can# is can0|1|2|3
sysirq is CAN system interrupt number, up to 3 IRQ numbers
                  [-a]
                  [-b string]
                  [-B presdiv,propseg,pseg1,pseg2,rjw]
                  [-c number]
                  [-d string]
                  [-D presdiv,propseg,pseg1,pseg2,rjw]
                  [-f]
                  [-h]
                  [-i midrx[,midtx]]
                  [-I]
                  [-k clksrc[,freq]]
                  [-l]
                  [-m number]
                  [-M]
                  [-n number]
                  [-o]
                  [-p port]
                  [-q number]
                  [-r number[,number[,number]]
                  [-R]
                  [-s]
                  [-S]
                  [-t]
                  [-u number]
                  [-v]
                  [-w]
                  [-x]
                  [-z]

Runs on:

QNX OS

Options:

These are the options available for this driver.

can#

The CAN number to use, which can be can0, can1, can2, can3.

sysirq

The CAN system interrupt number, up to 3 IRQ numbers

-a

Disable the AUTOBUS. By default, the AUTOBUS is enabled.

-b bitrate

Use a predefined bitrate. The valid values you can specify are 50K, 125K, 250K, 1Mor 500K. The default is 50K.

-B presdiv,propseg,pseg1,pseg2,rjw

Manually define the bitrate rate as a hexadecimal value. For each value, these conditions apply:

presdiv, specifies the bitrate prescaler.
propseg specifies the propagation segment time.
pseg1 specifies the bitrate time segment 1 must be less than or equal to 0x7.
pseg2 specifies the bitrate time segment 2 must be less than or equal to 0x7 but can't be zero (0x0).
rjw specifies the sync jump rate must be less than or equal to 0x3.

-c

Set and enable TDC offset (available for CAN-FD drivers)

-d

Predefined data bitrate for CAN-FD (50K, 125K, 250K, 500K, 1M, 5M, default 50K)

-D presdiv,propseg,pseg1,pseg2,rjw

Manually define the bitrate rate for CAN-FD as a hexadecimal value. For each value, these conditions apply:

presdiv, specifies the bitrate prescaler.
propseg specifies the propagation segment time.
pseg1 specifies the bitrate time segment 1 must be less than or equal to 0x7.
pseg2 specifies the bitrate time segment 2 must be less than or equal to 0x7 but can't be zero (0x0).
rjw specifies the sync jump rate must be less than or equal to 0x3.

-f

CAN-FD mode

Note:

"-f" option shouldn't be used on old FLEXCAN controller(eg. the one found on imx8qm/qxp SOC)

-h

Single message buffer[14MB], default dual buffer[28MB]

Note:

"-h" is mandatory if the FLEXCAN controller(eg. the one found on imx8qm/qxp SOC) doesn't support dual buffer

-i midrx[,midtx]

The starting receive and transmit message ID. The starting default ID is 0x100C0000.

-I

Enable IO privity

-k clksrc[,freq]

Set clock source (ref_clk|ext_clk) and frequency. The default is ref_clk,80000000

Note:

If supported by FLEXCAN IP.

-l

Listen only Mode

-m timestamp

Set the initial local timestamp as a hexadecimal number. The initial timestamp is 0x00000008.

-M

Disable MECR

Note:

"-M" is mandatory for certain FLEXCAN controllers(eg. the one found on the i.MX8M Plus SOC)

-n number

Number of each device mailbox message buffer (default 128 for CAN, 28 for CAN-FD).

-o

Enable CAN FD ISO

-p port

Base address of Flexcan

-q number

Client wait queue length for each mailbox

-r number[,number[,number]]

IRQ number, up to 3 IRQ numbers

-R

Enable raw mode, send and receive both standard and extended messages (doesn't require the -x option).

-s

Enable triple bitrate sample (default single sample).

-S

Message data endian swap

-t

Enable the self-test loopback mode. By default, the self-test loopback mode is disabled.

-u can_unit_num

CAN unit number. The default is 1.

-v

Increase driver verbosity

-w

The lowest buffer is transmitted first.

-x

Enable extended 29-bit CAN message ID. The default is 11-bit MID.

-z

Enable the timer synchronization. By default, it's disabled.

Examples:

S32g in loopback mode:

devcan-flexcan -t -I -S can0,0x45,0x47,0x48

i.MX8 in loopback mode:
```
devcan-flexcan -t -h can0
```

i.MX8MP using 80MHz ref clock:

devcan-flexcan -h -M -b250K -k ref_clk,80000000 -u1 can0

Page updated: September 26, 2025