Recans A0

Recans A0 has two controllers, one is based on RP2040, the other on MCP2515.

The MCP2515 CAN controller

sudo mount -o remount,rw /boot
sudo armbian-add-overlay /boot/overlay-user/sun50i-a64-mcp251x.dts
sudo mount -o remount,ro /boot

After booting:

sudo gpioset 1 165=0
sudo modprobe -r mcp251x
sudo modprobe mcp251x
dmesg | grep mcp

sudo ip link set can0 type can bitrate 125000
sudo ip link set can0 txqueuelen 128
sudo ip link set up can0

Interrupt: STEP7 = PL11

sudo apt install net-tools can-utils

cansend can1 5A1#11.2233.44556677.88

ip -details link show can0

~/klippy-env/bin/python ~/klipper/scripts/canbus_query.py can0

candump -tz -Ddex can0,#FFFFFFFF

To compile the RP2040 with klipper:

cd ~/klipper
cp test/configs/rp2040.config .config
make menuconfig
-- Communication interface = RP2040
-- RX = GPIO4
-- TX = GPIO5
make
sudo apt install libusb-1.0-0-dev
sudo FLASH_DEVICE="2e8a:0003" make flash

Hardware Errata

SPI_CLK and SPI_MOSI are interchanged and need to be fixed.
/RESET is floating.

Error messages

When sending: - write: No buffer space available

Got error -1 in can write: (105)No buffer space available

After that I get:

DROPCOUNT: dropped 109 CAN frames on 'can0' socket (total drops 576)

(302.908159) can0 RX - - 20000004 [8] 00 01 00 00 00 00 00 00 ERRORFRAME

       controller-problem{rx-overflow}

And the INT pin remains low. Needs a restart.

Debug

During init/reset:

TX: 0xC0 = RESET

TX: 0x03 0x0E 0x00 = READ CANSTAT
RX: 0x00 0x00 0x80 = Device is in Configuration mode

TX: 0x03 0x0F 0x00 = READ CANCTRL
RX: ? 

TX: 0x02 0x0F 0x20 = WRITE CANCTL = Sleep Mode

When trying to set interface up:

TX: 0x02 0x0F 0x80 = WRITE CANCTRL REQOP2 = Configuration Mode
RX: 0x00 0x00 0x00

TX: 0x03 0x0E 0x00 = READ CANSTAT
RX: 0x00 0x00 0x64 = OPMOD[2:0] = 0b011, ICOD[2:0] = 0b010

Device is in Listen-Only mode, Wake-up interrupt

It seems that the bring up sequence interferes with the initialization. Must make sure the mcp2515 probing is done after power is applied.