Mity CPU Platforms » MitySOM-AM57X

Sandeep Sivadas wrote:

Hi,

We designed our own custom AM5728 board with two DP83822 PHYs. Desired phy address are phy0 and phy 1.
In the schematic shown , we removed R219 to make it to PHY 1. The other DP83822 has COL pin pull down with 2.2k resistance is R55.
eth0 and eth1 is listed when giving ifconfig command. But when connecting with PC, following message coming continuously, when the ethernet cable is connected with PC and custom AM5728 Board

[ 661.602356] prueth pruss2_eth eth1: Link is Down
[ 662.642615] prueth pruss2_eth eth1: Link is Up - 100Mbps/Full - flow control off
[ 664.722383] prueth pruss2_eth eth1: Link is Down
[ 666.802613] prueth pruss2_eth eth1: Link is Up - 100Mbps/Full - flow control off
[ 668.882374] prueth pruss2_eth eth1: Link is Down

Do the link lights on the ethernet jack also go on and off?

We tried the commands in the wiki page. results are attached in the text file. Please have a look into this.
Attaching the Schematic files of DP83822 also.

I don't see anything wrong with your schematic.

Thanks and regards
Sandeep S

Q: Do the link lights on the ethernet jack also go on and off?
Yes. Left side led of RJ45 is go on and off. When we connect to PC, the ethernet link is showing not connected.

With regards
Sandeep S

Sandeep Sivadas wrote in RE: Ethernet Connectivity issues with DP83822:

Q: Do the link lights on the ethernet jack also go on and off?
Yes. Left side led of RJ45 is go on and off. When we connect to PC, the ethernet link is showing not connected.

If the phy link goes up and down, we can ignore the processor side of things. The phy itself handles establishing a link. It's very unusual that it would be toggling like that.

I'd recommend getting an oscilloscope and probing all the voltages going to the PHY as well as the reset line.

Hi,

I will verify the voltage levels on each lines.
1. For "PRU2MII1RESETn" we are using GPIO 1_4 and modified the Kernel and uboot for GPIO 1_4. we made the modification in

/processor-sdk-u-boot/board/cl/mitysom-57x/board.c

#define GPIO_PRU2_MII1_RESETn GPIO_TO_PIN(1, 4) // previously #define GPIO_PRU2_MII1_RESETn GPIO_TO_PIN(5, 9)

Changed aliases as below in "am57xx-mitysom-baseboard.dtsi"
aliases {
display0 = &hdmi0;
ethernet0 = &pruss2_emac0;
ethernet1 = &pruss2_emac1;
sound0 = &sound0;
sound1 = &hdmi;
spi4 = &mcspi4;
};

2. Changed made as below in "am57xx-mitysom-baseboard.dtsi"

&pruss2_mdio {
status = "okay";

reset-gpios = <&gpio5 8 GPIO_ACTIVE_LOW>,
                <&gpio1 4 GPIO_ACTIVE_LOW>;  //<&gpio5 9 GPIO_ACTIVE_LOW>;
    reset-delay-us = <20>;   /* PHY datasheet states 10uS min */

pruss2_eth0_phy: ethernet-phy@0 {
        reg = <0>;
        interrupt-parent = <&gpio3>;
        interrupts = <30 IRQ_TYPE_EDGE_FALLING>;
    };

pruss2_eth1_phy: ethernet-phy@1 {
        reg = <1>;
        interrupt-parent = <&gpio3>;
        interrupts = <31 IRQ_TYPE_EDGE_FALLING>;
    };
};

3. In mux_data.h modified the code as shown below.

//{MCASP1_AXR7, (M14 | PIN_INPUT_PULLUP)},    /* D12 mcasp1_axr7.gpio5_9 PRU2_MII1_RESETn[OUT] external pullup */
{MCASP2_AXR4, (M14 |PIN_INPUT_PULLUP)},            /* D12 mcasp2_axr4.gpio1_4 PRU2_MII1_RESETn[OUT] external pullup */

Any other changes we have to do if we are using PRU2_MII1_RESETn GPIO 1_4 other than GPIO 5_9

Please have a look in to this.

Thanks and regards
Sandeep S

3. In mux_data.h modified the code as shown below.

Did you also comment out or change the original MCASP2_AXR4 line. Just to make sure that pinmux isn't getting set twice.

    {MCASP2_AXR4, (M1 | PIN_INPUT)},    /* D15 mcasp2_axr4.mcasp8_axr0 AIC_DIN */

Hi,

The problem is solved now. We removed the 165 ohm resistance connected in the TDP,TDM, RDP and RDM lines. Now the ethernet connectivity is okay and ping also working.

Now we are facing another problem. We are planned for RJ45 and SFP using the PHY DP83822IRHBR. But in one TI forum I saw that this PHY didn't support 100 base FX communication. I need a PHY IC which can support both Copper and fiber communication.

Could you please confirm that DP83822IRHBR support with copper or fiber optic communication. We purchased some ICs. If it is not supported with copper and fiber we have to buy another series IC which have both copper and fiber support.

Thanks and regards
Sandeep S

Sandeep Sivadas wrote in RE: Ethernet Connectivity issues with DP83822:

Hi,

The problem is solved now. We removed the 165 ohm resistance connected in the TDP,TDM, RDP and RDM lines. Now the ethernet connectivity is okay and ping also working.

Ahh good catch, I didn't notice those when looking through your schematic.

Now we are facing another problem. We are planned for RJ45 and SFP using the PHY DP83822IRHBR. But in one TI forum I saw that this PHY didn't support 100 base FX communication. I need a PHY IC which can support both Copper and fiber communication.

According to the datasheet: https://www.ti.com/lit/ds/symlink/dp83822i.pdf, dp83822if and dp83822hf support 100base-fx. Though I'm not sure you can do both at the same time.

Could you please confirm that DP83822IRHBR support with copper or fiber optic communication. We purchased some ICs. If it is not supported with copper and fiber we have to buy another series IC which have both copper and fiber support.

I believe you want, DP83822IFRHBR

Thanks and regards
Sandeep S

Hi,

Thank you for your prompt support.

Is there any modifications to be done in the kernel side for the fiber optic communication using SFP modules ?

With regards
Sandeep S

Sandeep Sivadas wrote in RE: Ethernet Connectivity issues with DP83822:

Hi,

Thank you for your prompt support.

Is there any modifications to be done in the kernel side for the fiber optic communication using SFP modules ?

I don't know, I've never used an SFP in a design before.

Hi,

Okay..will try with DP83822IFRHBR.
Thank you for your support.

With regards
Sandeep S