PROCESSOR-SDK-AM62X: Testing CAN Interface on Am62x Sk

Hi TI,

kindly can anyone guide me through the CAN inteface Testing on Am62x. We are struggling on this for a while.but cant able to find the solution.

Regards,

Murali C 

Hi Murali, 
The overlay files/dtbos are not found in the standard wic image. You will need to build them by following certain commands in the PSDK linux source tree. After you build the overlay k3-am625-sk-mcan.dts file, you can copy it into the root partition for MCAN to work. 
You can refer to the following article for detailed reference: 4.1.7. How to enable DT overlays on AM625 SK — Processor SDK AM62x Documentation

Regards,
Aparna

Hi Aparna,

Thanks for the reply..

I had build the overlay file, and copied the k3-am62x-sk-mcan.dtbo file into /root/boot.

but when i tried to send data using cansend command the CAN bus goes to off state.

i had setup two am62x sk board with two CAN transceivers.One act as Transmitter and the other act as Receiver.

Transmitter side:

ip link set can0 down.
ip link set can0 type can bitrate 125000

ip link set can 0 up

cansend can0 123#DEADBEEF

[ 170.474360] can: controller area network core
[ 170.478830] NET: Registered protocol family 29
[ 170.490795] can: raw protocol
root@am62xx-evm:~# [ 170.498422] m_can_platform 20701000.can can0: bus-off

Receiver Side:

ip link set can0 down.
ip link set can0 type can bitrate 125000

ip link set can 0 up

candump can0

Kindly find the connection diagram below.

We followed the below link to test can interface.

https://software-dl.ti.com/processor-sdk-linux/esd/AM62X/08_05_00_21/exports/docs/linux/Foundational_Components/Kernel/Kernel_Drivers/MCAN.html

kindly provide some solution to overcome this issue, we are struggling on this for almost 2 weeks.

Regards

Murali C

Murali,

Please confirm that you also have pin 2 of the TCAN1051 connected to ground, and that you have the recommended 0.1uF decoupling capacitor between VCC and GND near the TCAN1051 XCVR.

The other issue I see is that you have the pin 8 silent pin pulled high. This puts the transceiver in silent mode, meaning that the transmitter is disabled. This will definitely cause a bus-off state.

Thanks,

Stuart

Hi Stuart,

Thanks for the reply, kindly find my response in blue below,

Please confirm that you also have pin 2 of the TCAN1051 connected to ground, and that you have the recommended 0.1uF decoupling capacitor between VCC and GND near
the TCAN1051 XCVR.

Yes, we have connected pin 2 to ground and have a 0.uf capacitor between VCC and Gnd.

The other issue I see is that you have the pin 8 silent pin pulled high. This puts the transceiver in silent mode, meaning that the transmitter is disabled.
This will definitely cause a bus-off state.

Yes, we have gone through the Datasheet and connected Pin 8 to ground, so that the transceiver will be in Normal mode.(Both Transmitter and Receiver Works).

But still we can't able to get the output, we are still facing the same issue.

Kindly find the updated block diagram for your reference.

Regards,
Murali C

Hi stuart,

Sorry! for the late reply. yes we tried probing the TX pin using Logic Analyzer. we found some signals on that TX Pin. So we started debugging the transceiver connections, where we found a connection issue. After fixing that, MCAN Bus started working and we are able to send and receive Data.

Thanks for the help.

Regards,

Murali Chikkanna 

Hi Stuart,
              I am am facing similar issue, I have added mcan overlay on 'k3-am625-sk.dts. Here is my dts after adding mcan overlay:-

// SPDX-License-Identifier: GPL-2.0
/*
 * AM625 SK: https://www.ti.com/lit/zip/sprr448
 *
 * Copyright (C) 2021-2022 Texas Instruments Incorporated - https://www.ti.com/
 */

/dts-v1/;

#include <dt-bindings/leds/common.h>
#include <dt-bindings/gpio/gpio.h>
#include <dt-bindings/net/ti-dp83867.h>
#include <dt-bindings/pinctrl/k3.h>
#include <dt-bindings/interrupt-controller/irq.h>

#include "k3-am625.dtsi"
#include "k3-am62x-sk-common.dtsi"


/ {
        compatible =  "ti,am625-sk", "ti,am625";
    model = "Platform-AM625-SK-13mar2023";
	transceiver1: can-phy0 {
                compatible = "ti,tcan1042";
                #phy-cells = <0>;
                max-bitrate = <5000000>;
        };
	wlan_lten: regulator-5 {
                compatible = "regulator-fixed";
                regulator-name = "wlan_lten";
                regulator-min-microvolt = <3300000>;
                regulator-max-microvolt = <3300000>;
                regulator-always-on;
                vin-supply = <&vcc_3v3_sys>;
                gpios = <&exp1 11 GPIO_ACTIVE_LOW>;
        };

        wlan_en: regulator-6 {
                /* OUTPUT of SN74AVC2T244DQMR */
                compatible = "regulator-fixed";
                regulator-name = "wlan_en";
                regulator-min-microvolt = <1800000>;
                regulator-max-microvolt = <1800000>;
                enable-active-high;
                vin-supply = <&wlan_lten>;
                gpios = <&main_gpio0 71 GPIO_ACTIVE_HIGH>;
                pinctrl-names = "default";
                pinctrl-0 = <&wlan_en_pins_default>;
        };
};

&main_pmx0 {
        wlan_en_pins_default: wlan-en-pins-default {
                pinctrl-single,pins = <
                        AM62X_IOPAD(0x124, PIN_OUTPUT, 7) /* (A23) MMC2_SDCD.GPIO0_71 */
                >;
        };

        main_mmc2_pins_default: main-mmc2-pins-default {
                pinctrl-single,pins = <
                        AM62X_IOPAD(0x120, PIN_INPUT, 0) /* (C24) MMC2_CMD */
                        AM62X_IOPAD(0x118, PIN_INPUT, 0) /* (D25) MMC2_CLK */
                        AM62X_IOPAD(0x114, PIN_INPUT, 0) /* (B24) MMC2_DAT0 */
                        AM62X_IOPAD(0x110, PIN_INPUT, 0) /* (C25) MMC2_DAT1 */
                        AM62X_IOPAD(0x10c, PIN_INPUT, 0) /* (E23) MMC2_DAT2 */
                        AM62X_IOPAD(0x108, PIN_INPUT, 0) /* (D24) MMC2_DAT3 */
                        AM62X_IOPAD(0x11c, PIN_INPUT, 0) /* (#N/A) MMC2_CLKB */
                >;
        };

        main_wlirq_pins_default: main-wlirq-pins-default {
                pinctrl-single,pins = <
                        AM62X_IOPAD(0x128, PIN_INPUT, 7) /* (B23) MMC2_SDWP.GPIO0_72 */
                >;
        };

    main_spi2_pins_default: main-spi2-pins-default {
                pinctrl-single,pins = <
                        AM62X_IOPAD(0x1B0, PIN_INPUT, 1)   /* (A20) SPI2_CLK pins  on expansion Header*/
            AM62X_IOPAD(0x1AC, PIN_OUTPUT, 1)  /* (E19) SPI2_CS0 pins on expansion Header */
            AM62X_IOPAD(0x194, PIN_INPUT, 1)   /* (B19) SPI2_D0 pins on expansion Header */
            AM62X_IOPAD(0x198, PIN_INPUT, 1)   /* (A19) SPI2_D1 pins on expansion Header */
                >;
        };
	main_mcan0_pins_default: main-mcan0-pins-default {
        pinctrl-single,pins = <
            AM62X_IOPAD(0x1dc, PIN_INPUT, 0)  /* (E15) MCAN0_RX */
            AM62X_IOPAD(0x1d8, PIN_OUTPUT, 0) /* (C15) MCAN0_TX */
        >;
    };
};

&main_i2c1 {
	exp1: gpio@22 {
		compatible = "ti,tca6424";
		reg = <0x22>;
		gpio-controller;
		#gpio-cells = <2>;
		gpio-line-names = "GPIO_CPSW2_RST", "GPIO_CPSW1_RST",
				   "PRU_DETECT", "MMC1_SD_EN",
				   "VPP_LDO_EN", "EXP_PS_3V3_En",
				   "EXP_PS_5V0_En", "EXP_HAT_DETECT",
				   "GPIO_AUD_RSTn", "GPIO_eMMC_RSTn",
				   "UART1_FET_BUF_EN", "WL_LT_EN",
				   "GPIO_HDMI_RSTn", "CSI_GPIO1",
				   "CSI_GPIO2", "PRU_3V3_EN",
				   "HDMI_INTn", "TEST_GPIO2",
				   "MCASP1_FET_EN", "MCASP1_BUF_BT_EN",
				   "MCASP1_FET_SEL", "UART1_FET_SEL",
				   "TSINT#", "IO_EXP_TEST_LED";

		interrupt-parent = <&main_gpio1>;
		interrupts = <23 IRQ_TYPE_EDGE_FALLING>;
		interrupt-controller;
		#interrupt-cells = <2>;

		pinctrl-names = "default";
		pinctrl-0 = <&main_gpio1_ioexp_intr_pins_default>;
	};
};

&sdhci2 {
	vmmc-supply = <&wlan_en>;
	pinctrl-names = "default";
	pinctrl-0 = <&main_mmc2_pins_default>;
	bus-width = <4>;
	non-removable;
	ti,fails-without-test-cd;
	cap-power-off-card;
	keep-power-in-suspend;
	ti,driver-strength-ohm = <50>;
	assigned-clocks = <&k3_clks 157 158>;
	assigned-clock-parents = <&k3_clks 157 160>;

	#address-cells = <1>;
	#size-cells = <0>;
	wlcore: wlcore@2 {
		compatible = "ti,wl1837";
		reg = <2>;
		pinctrl-names = "default";
		pinctrl-0 = <&main_wlirq_pins_default>;
		interrupt-parent = <&main_gpio0>;
		interrupts = <72 IRQ_TYPE_EDGE_FALLING>;
	};
};
&main_mcan0 {
        status = "okay";
        pinctrl-names = "default";
        pinctrl-0 = <&main_mcan0_pins_default>;
        phys = <&transceiver1>;
};
&ospi0 {
	flash@0 {
		compatible = "jedec,spi-nor";
		reg = <0x0>;
		spi-tx-bus-width = <8>;
		spi-rx-bus-width = <8>;
		spi-max-frequency = <25000000>;
		cdns,tshsl-ns = <60>;
		cdns,tsd2d-ns = <60>;
		cdns,tchsh-ns = <60>;
		cdns,tslch-ns = <60>;
		cdns,read-delay = <4>;
		cdns,phy-mode;

		partitions {
			compatible = "fixed-partitions";
			#address-cells = <1>;
			#size-cells = <1>;

			partition@0 {
				label = "ospi.tiboot3";
				reg = <0x0 0x80000>;
			};

			partition@80000 {
				label = "ospi.tispl";
				reg = <0x80000 0x200000>;
			};

			partition@280000 {
				label = "ospi.u-boot";
				reg = <0x280000 0x400000>;
			};

			partition@680000 {
				label = "ospi.env";
				reg = <0x680000 0x40000>;
			};

			partition@6c0000 {
				label = "ospi.env.backup";
				reg = <0x6c0000 0x40000>;
			};

			partition@800000 {
				label = "ospi.rootfs";
				reg = <0x800000 0x37c0000>;
			};

			partition@3fc0000 {
				label = "ospi.phypattern";
				reg = <0x3fc0000 0x40000>;
			};
		};
	};
};
&main_spi2{
    pinctrl-names = "default";
 	pinctrl-0 = <&main_spi2_pins_default>;
    status = "okay";    
    adc@0 {
            compatible = "ti,adc128s052";
            reg = <0>;
            spi-max-frequency = <1000000>;
            #io-channel-cells = <1>;
        };
};

/*
&main_i2c0 {
	#address-cells = <1>;
	#size-cells = <0>;

	touchscreen@41 {
		compatible = "ilitek,ili251x";
		reg = <0x41>;
		interrupt-parent = <&exp1>;
		interrupts = <15 IRQ_TYPE_EDGE_FALLING>;
		reset-gpios = <&exp2 18 GPIO_ACTIVE_LOW>;
	};
};
*/

I can't test mcan after booting my image to sk-am62 evaluation board, however I stop boot on u-boot and use following command:-

setenv name_overlays k3-am625-sk-mcan.dtbo
boot

Now I can test mcan successfully. Please confirm why mcan not coming by default with my changes.Thanks

Hello,

In u-boot, can you try the saveenv command, like so:

# setenv name_overlays k3-am625-sk-mcan.dtbo

# saveenv

# boot

Then reboot the board to see if the overlay is applied.

Hi Mendez,
  yes after applying these command, its working. But please confirm how to do it with dts file

Hi Mandez, I tried your patch. But it didn't solve my issue

Hello Tabish,

To better help you, could you please explain what is not working? What are the symptoms? A console log could be useful and what is your physical setup?

I am using CAN module (TJA1050 - robu.in/product/tja1050-can-controller-bus-driver-interface-module/?gclid=EAIaIQobChMIooKRiMeU_gIVkn0rCh3rXwMTEAQYAyABEgLtzPD_BwE) with my sk-am62 evaluation board.

I have connected J3 header pin number 8 with module Rx pin & pin number 10 with module Tx pin. I am providing power to the module with J24v header on my board. I am using PCAN tool (https://www.peak-system.com/PCAN-USB.199.0.html?&L=1)  to monitor signals. 

To send the signal, I am referring this documents :- https://software-dl.ti.com/processor-sdk-linux/esd/AM64X/08_02_00_23/exports/docs/linux/Foundational_Components/Kernel/Kernel_Drivers/MCAN.html

following are my commands:-

ip link set can0 type can bitrate 1000000

ip link set can0 up

cansend can0 123#DEADBEEF

I got nothing on PCAN.

I also tried hardware self test by using following command:-

ip link set can0 up type can bitrate 1000000 dbitrate 2000000 fd on loopback on

candump can0 &

cansend can0 300#AC.AB.AD.AE.75.49.AD.D1

I got following result:-

root@am62xx-lrd:~# ip link set can0 up type can bitrate 1000000 dbitrate 2000000 fd on loopback on
[   80.746976] IPv6: ADDRCONF(NETDEV_CHANGE): can0: link becomes ready
root@am62xx-lrd:~# candump can0 &
[1] 1031
interface = can0, family = 29, type = 3, proto = 1
root@am62xx-lrd:~# [   96.514163] can: raw protocol

root@am62xx-lrd:~# cansend can0 300#AC.AB.AD.AE.75.49.AD.D1
interface = can0, family = 29, type = 3, proto = 1
<0x001> [1] 2c 
<0x001> [1] 2c

Also, I observed that after connecting my module with J24, voltage gets drop to 1.1 V from 3.3 V. To cross check if module is faulty, I tried same setting with a different board, there is no voltage drop in that case, also CAN is working fine there.

Hello tabish,

Could you try the following and show your results:

# ip link set can0 type can bitrate 1000000
# ip link set can0 up
# cansend can0 123#DEADBEEF
# ip -d -s link show can0
# dmesg | grep can

Thank you.