I have the same problem with DP83869HM in 1000M Media Convertor Mode as in e2e.ti.com/.../3144830. Is there a solution to that problem?
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I have the same problem with DP83869HM in 1000M Media Convertor Mode as in e2e.ti.com/.../3144830. Is there a solution to that problem?
Hi Alexander,
You may want to add a digital restart to the register programming sequence such that it reads the following:
Are you able to correctly access the extended registers? Can you read back the STRAP_STS register?
Thank you,
Nikhil
Hello Nikhil,
I programmed the following registers:
After programming links on my PC and Fiber side goes down.
Here are the values that I have read out of some of the registers.
BMSR = 0x7969 (bit LINK_STS1 =0)
STRAP_STS = 0x08CE
FX_STS = 0x6149 (bit STTS_LINK_STATUS=0)
1KSCR = 0xF000
SERDES_SYNC_STS = 0x0220
I don't understand why bits *LINK_STATUS in DP83869HM show the Link Down, but on PC and FIber side show the Link Status is Up?
Where can I get a 0x01EC register description? There's no description of it in the DP83869HM datasheet .
Hi Alexander,
I have the following feedback for the schematic:
As an additional debug step, have you tried the Media Converter mode using two DP83869s?
Thank you,
Nikhil
Hello Nikhil,
I have replaced:
The situation has not changed.
I can't check two DP83869s in media converter mode on my board.
What does the register 0x01EC do? There's no description of it in the DP83869HM datasheet .
I tried to change the operating mode to SGMII to Copper in DP8369. Then i read register BMSR = 0x796d (bit LINK_STS1 =1).
When changing the operating mode to 1000Base-T to 1000Base-X in DP8369. register BMSR = 0x7969 (bit LINK_STS1 =0).
What is the difference in these modes for the 1000BASE-T communication procedure? Why is it in the media converter mode link bit is down?
Thank you
Hi Alexander,
Are you also seeing this issue in RGMII to Fiber mode? If RGMII to Fiber works, this may narrow down our issue to the Fiber side. .
Register 1EC is a link loss pass through register. If you have the PHY acting as a media converter between a Fiber and Copper device, both devices will show link on either side of the PHY. If one device, for example on the fiber side of the PHY, drops link, you would also want the device on the copper side of the PHY to drop link so this device isn't sending messages to the PHY while there is no link on the Fiber side. Enabling link loss pass through will recognize that link has dropped on one side of the PHY, and drop link on the other side.
Thank you,
Nikhil
Hello Nikhil,
The problem has been solved. After examining the behavior of DP8396, the following was found:
If the 1000Base-T to Fiber mode is set using strap resistors. When the power is on, the contents of the registers are as follows:
and so there was no connection.
Then I set the SGMII to Copper mode using strap resistors. When I turned on the power, the contents of the registers were like this:
there was no connection.
After that, I programmed the following via MDIO:
and then the connection appeared and worked well and the register contents were like this:
Although the problem is solved, I am interested in whether the 1000Base-T to Fiber mode should work if the setting is made only with strap resistors and there is no possibility to adjust it by software?
Thank you
Hi Alexander
For the case where you are strapping SGMII to Copper, you are reading bit LINK_STS1=1 in BSMR but there is no connection?
As for using Media Converter mode with only straps, the datasheet specifies in section 9.4.7 that a register write is necessary for operation in Media Converter mode.
Thank you,
Nikhil