AM335x with LAN8710a RMII mode : packet loss

AFM

Intellectual 560 points

hello,

i m trying to use the LAN8710A for a customer board based on AM335x with RMII mode.

1-) clock 50MHZ sourced from AM335x :

==> when trying to ping the board on network 100Mb, i get near of 40% packet loss.

==> when trying to ping the board on network 10Mb, no packet loss

2-) clock 50MHz sourced from external oscillator:

==> can't get the LAN8710A work: i made changes on gmii_sel register (rmii1_io_clk_en bit) but with no results. did i miss somethings on configuration ?

the Pinmux is configured as RMII mode,

thanks

over 11 years ago

0 Biser Gatchev-XID over 11 years ago

TI__Guru**** 393215 points

Hi Mokh,

The answer to both of your questions can be found in AM335X Errata Rev.E, Advisory 1.0.16. The first case will simply not work. In the second case check if you have receiver enabled in the pinmux.

0 AFM over 11 years ago in reply to Biser Gatchev-XID

Intellectual 560 points

i updated the pinmux for the rmii1_refclk.rmii1_refclk pin and i changed the register gmii_sel. is there any other updates ?

0 Biser Gatchev-XID over 11 years ago in reply to AFM

TI__Guru**** 393215 points

From a hardware point of view no.

0 Steve Kipisz over 11 years ago in reply to Biser Gatchev-XID

TI__Genius 15510 points

From a software point of view, can you post your source code that sets the pinmux and the gmii_sel register?

Steve K.

0 AFM over 11 years ago in reply to Steve Kipisz

Intellectual 560 points

1) pinmux configuration:

static struct pinmux_config rmii1_pin_mux[] = {
{"mii1_crs.rmii1_crs_dv", OMAP_MUX_MODE1 | AM33XX_PIN_INPUT_PULLDOWN},
{"mii1_rxerr.mii1_rxerr", OMAP_MUX_MODE1 | AM33XX_PIN_INPUT_PULLDOWN},
{"mii1_txen.mii1_txen", OMAP_MUX_MODE1 | AM33XX_PIN_OUTPUT},
{"mii1_txd1.mii1_txd1", OMAP_MUX_MODE1 | AM33XX_PIN_OUTPUT},
{"mii1_txd0.mii1_txd0", OMAP_MUX_MODE1 | AM33XX_PIN_OUTPUT},
{"mii1_rxd1.mii1_rxd1", OMAP_MUX_MODE1 | AM33XX_PIN_INPUT_PULLDOWN},
{"mii1_rxd0.mii1_rxd0", OMAP_MUX_MODE1 | AM33XX_PIN_INPUT_PULLDOWN},
{"rmii1_refclk.rmii1_refclk", OMAP_MUX_MODE0 | AM33XX_PIN_INPUT_PULLDOWN},
{"mdio_data.mdio_data", OMAP_MUX_MODE0 | AM33XX_PIN_INPUT_PULLUP},
{"mdio_clk.mdio_clk", OMAP_MUX_MODE0 | AM33XX_PIN_OUTPUT_PULLUP},
{NULL, 0},
};

2) Register gmii_sel

#define RGMII_MODE_ENABLE 0x09

on the board, we are using the ETH0 as RMII1 and ETH1 as RGMII2: is that related to the dual mac configuration ? how can fix that ?

0 AFM over 11 years ago in reply to AFM

Intellectual 560 points

any feedback about this configuration ?

0 AFM over 11 years ago in reply to AFM

Intellectual 560 points

any member can confirm this configuration ?

0 Steve Kipisz over 11 years ago in reply to AFM

TI__Genius 15510 points

Your gmii_sel register is incorrect. You need to set bit 6 to 1.

Steve K.

0 AFM over 11 years ago in reply to Steve Kipisz

Intellectual 560 points

we tried before with 0x49 and 0xF9 but we get the same behavior of the ethernet interface. any propositions ?

0 AFM over 11 years ago in reply to AFM

Intellectual 560 points

even on beaglebone, they switch from RMII to MII on future revision.

it appears that RMII is not the best choice with the AM335x family.

0 peaves over 11 years ago in reply to AFM

TI__Guru 62875 points

RMII was changed to MII on BeagleBone before the issue described in AM335x Silicon Errata Advisory 1.0.16 was fully understood. RMII has been proven to work by using an external low jitter 50MHz clocksource for the RMII Reference clock.

Can you send us a snapshoot of the LAN8710 portion of your schematic?

Regards,
Paul

0 AFM over 11 years ago in reply to peaves

Intellectual 560 points

any remarks ?

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AM335x with LAN8710a RMII mode : packet loss