2 Channel CAN BUS FD Shield for Raspberry Pi - Error Experienced

Hi,



I have a Seeed CAN BUS Card and have installed it on top of a Sixfab Pi 3G-4G/LTE Base Shield V2 which is using USB cable for comms.

I havent wired the CAN card up yet to a CAN circuit but ran the install procedures on Seeed website.

Then got this on dmesg | grep spi



[ 5.201525] mcp25xxfd spi0.0: MCP2517 successfully initialized.

[ 5.226249] mcp25xxfd spi1.0: MCP2517 successfully initialized.

[ 5049.919314] mcp25xxfd spi0.0 can0: CAN Bus error experienced

[ 5049.920374] mcp25xxfd spi0.0 can0: CAN Bus error experienced

[ 5375.909019] mcp25xxfd spi0.0 can0: CAN Bus error experienced

[ 5375.909960] mcp25xxfd spi0.0 can0: CAN Bus error experienced



Got this msg from ip -details link show can0



4: can0: <NOARP,UP,LOWER_UP,ECHO> mtu 72 qdisc pfifo_fast state UP mode DEFAULT group default qlen 65536

link/can promiscuity 0 minmtu 0 maxmtu 0

can <LISTEN-ONLY,BERR-REPORTING,FD> state ERROR-PASSIVE (berr-counter tx 128 rx 0) restart-ms 1000

bitrate 500000 sample-point 0.875

tq 25 prop-seg 34 phase-seg1 35 phase-seg2 10 sjw 1

mcp25xxfd: tseg1 2…256 tseg2 1…128 sjw 1…128 brp 1…256 brp-inc 1

dbitrate 8000000 dsample-point 0.600

dtq 25 dprop-seg 1 dphase-seg1 1 dphase-seg2 2 dsjw 1

mcp25xxfd: dtseg1 1…32 dtseg2 1…16 dsjw 1…16 dbrp 1…256 dbrp-inc 1

clock 40000000numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535



Can anyone suggest what might be happening ?

Do I need to wire to a CAN circuit first or ?



Thanks



Chris