2

On a Raspberry Pi 1 Mod. B+

Raspberry Pi reference 2021-01-11
Generated using pi-gen, https://github.com/RPi-Distro/pi-gen, 21090519d85bdaa1615d5d5057d37b09368ea5d2, stage2

Oct 29 2021 10:49:08
Copyright (c) 2012 Broadcom
version b8a114e5a9877e91ca8f26d1a5ce904b2ad3cf13 (clean) (release) (start)

Linux raspberrypi 5.10.63-v7+ #1459 SMP Wed Oct 6 16:41:10 BST 2021 armv7l GNU/Linux

A CAN signal physicaly connected to CAN0 produces output on candump can1.

What can be the reason and what to do to eliminate the bug?

A waveshare 2-ch-can-hat connected to raspberry B3+

INT1 --- Pin 29 GPIO 5

INT0 --- Pin 31 GPIO 6

CS1 ---- Pin 11 GPIO 17 (SPI1 CE1)

CS2 ---- Pin 12 GPIO 18 (SPI1 CE0)

SCK ---- Pin 40 GPIO21 (SPI1 SCLK)

MOSI -- Pin 38 GPIO20 (SPI1 MOSI)

MISO -- Pin 35 GPIO19 (SPI1 MISO)

GND --- Pin 6 GND

5V ----- Pin 1 5V

with a /boot/config.txt loading dt overlays:

dtoverlay=spi1-2cs,cs0_spidev=off,cs1_spidev=off

dtoverlay=t-sp1-can0,oscillator=16000000,interrupt=5

dtoverlay=t-sp1-can1,oscillator=16000000,interrupt=6

t-sp1-can0.dtbo compiles from:

 /*  
*Device tree overlay for mcp251x/can0 on spi1.0
 */

/dts-v1/;
/plugin/;

/ {
    compatible = "brcm,bcm2835", "brcm,bcm2836", "brcm,bcm2708", "brcm,bcm2709";
    /* disable spi-dev for spi1.0 */
    fragment@0 {
        target = <&spi1>;
        __overlay__ {
            status = "okay";
        };
    };

    fragment@1 {
    target = <&spidev0>;
    __overlay__ {
        status = "disabled";
    };
    };

    /* the interrupt pin of the can-controller */
    fragment@2 {
        target = <&gpio>;
        __overlay__ {
            can0_pins: can0_pins {
                brcm,pins = <25>;
                brcm,function = <0>; /* input */
            };
        };
    };

    /* the clock/oscillator of the can-controller */
    fragment@3 {
        target-path = "/clocks";
        __overlay__ {
            /* external oscillator of mcp2515 on SPI0.0 */
            can0_osc: can0_osc {
                compatible = "fixed-clock";
                #clock-cells = <0>;
                clock-frequency  = <16000000>;
            };
        };
    };

    /* the spi config of the can-controller itself binding everything together */
    fragment@4 {
        target = <&spi1>;
        __overlay__ {
            /* needed to avoid dtc warning */
            #address-cells = <1>;
            #size-cells = <0>;
            can0: mcp2515@0 {
                reg = <0>;
                compatible = "microchip,mcp2515";
                pinctrl-names = "default";
                pinctrl-0 = <&can0_pins>;
                spi-max-frequency = <10000000>;
                interrupt-parent = <&gpio>;
                interrupts = <25 0x2>;
                clocks = <&can0_osc>;
            };
        };
    };
    __overrides__ {
        oscillator = <&can0_osc>,"clock-frequency:0";
        spimaxfrequency = <&can0>,"spi-max-frequency:0";
        interrupt = <&can0_pins>,"brcm,pins:0",<&can0>,"interrupts:0";
    };
};

t-sp1-can1.dtbo compiles from:

/*  * Device tree overlay for mcp251x/can1 on spi1.1 edited by petit_miner  */

/dts-v1/; /plugin/;

/ {
    compatible = "brcm,bcm2835", "brcm,bcm2836", "brcm,bcm2708", "brcm,bcm2709";
    /* disable spi-dev for spi1.1 */
    fragment@0 {
        target = <&spi1>;
        __overlay__ {
            status = "okay";
        };
    };

    fragment@1 {    target = <&spidev1>;    __overlay__ {
        status = "disabled";    };
    };

    /* the interrupt pin of the can-controller */
    fragment@2 {
        target = <&gpio>;
        __overlay__ {
            can1_pins: can1_pins {
                brcm,pins = <25>;
                brcm,function = <0>; /* input */
            };
        };
    };

    /* the clock/oscillator of the can-controller */
    fragment@3 {
        target-path = "/clocks";
        __overlay__ {
            /* external oscillator of mcp2515 on spi0.1 */
            can1_osc: can1_osc {
                compatible = "fixed-clock";
                #clock-cells = <0>;
                clock-frequency  = <16000000>;
            };
        };
    };

    /* the spi config of the can-controller itself binding everything together */
    fragment@4 {
        target = <&spi1>;
        __overlay__ {
            /* needed to avoid dtc warning */
            #address-cells = <1>;
            #size-cells = <0>;
            can1: mcp2515@1 {
                reg = <1>;
                compatible = "microchip,mcp2515";
                pinctrl-names = "default";
                pinctrl-0 = <&can1_pins>;
                spi-max-frequency = <10000000>;
                interrupt-parent = <&gpio>;
                interrupts = <25 0x2>;
                clocks = <&can1_osc>;
            };
        };
    };
    __overrides__ {
        oscillator = <&can1_osc>,"clock-frequency:0";
        spimaxfrequency = <&can1>,"spi-max-frequency:0";
        interrupt = <&can1_pins>,"brcm,pins:0",<&can1>,"interrupts:0";
    }; };

after booting dmesg | grep spi

[ 8.232885] mcp251x spi1.1 can0: MCP2515 successfully initialized. [ 8.245989] mcp251x spi1.0 can1: MCP2515 successfully initialized.

spi1.1 linked to can0 ! spi1.0 linked to can1 !

loading just one overlay results in the following errors:

dtoverlay=t-sp1-can0,oscillator=16000000,interrupt=5

 dmesg|grep spi ----> 
[    8.109524] mcp251x spi1.0: Cannot initialize MCP2515. Wrong wiring?
[    8.109766] mcp251x spi1.0: Probe failed, err=1



dtoverlay=t-sp1-can1,oscillator=16000000,interrupt=6

 dmesg|grep spi ----> 
[    8.109524] mcp251x spi1.1: Cannot initialize MCP2515. Wrong wiring?
[    8.109766] mcp251x spi1.1: Probe failed, err=19

and while loading only one overlay

cat /proc/interrupts shows no additional interupts

loading both overlays adds two interrupts

199:        0       0       0       0  pinctrl-bcm2835   6 Edge      spi1.1
200:    60961       0       0       0  pinctrl-bcm2835   5 Edge      spi1.0

hooking up an osciloscope :

GPIO5 -- int5(asociated with can0) is high and gets an interrupt

GPIO6 -- int6(asociated with can1) stays low

running

raspi-gpio get 5,6

in a loop confirms this reading

some other gory details can be found at https://github.com/raspberrypi/linux/issues/5346

1 Answer 1

0

After more testing -Hardware Error on GPIO 6 moved the Intrruped to GPIO 13 everything fine -- exept for the question just my board or a wider problem

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