DP83848J: DP83848J-Communication Issue between PHY IC and RJ 45 Jack

Jaya Shree C P

Prodigy 40 points

Part Number: DP83848J

Hi,

I am using an Altera Cyclone III and trying to communicate with DP83848JSQ from an FPGA.

Even I did not plug the RJ45 jack of Altera Cyclone III to PC, the link up status always high.

Kindly confirm the below connections was correct between PHY IC and RJ45 jack.

Note: TD+/- & RD+/- are the pins from PHY IC (DP83848J).

Regards,

Jaya Shree C P

over 3 years ago

0 Jaya Shree C P over 3 years ago

Prodigy 40 points

Adding one more point.,

Transformer used in the board: TG110-S055N2.

Please confirm whether this part can be used.

0 Gokul Koraganji over 3 years ago in reply to Jaya Shree C P

TI__Mastermind 19250 points

Hi Jaya Shree,

Can you please share the whole schematic including DP83848 and its connections to Altera Cyclone III?

--
Regards,
Gokul

0 Jaya Shree C P over 3 years ago in reply to Gokul Koraganji

Prodigy 40 points

Hi Gokul,

Schematics are as follows.,

i) PHY IC Connections:

ii) Altera Cyclone III Connections:

Please let me know if you need anything else.

Regards,

Jaya Shree C P

0 Gokul Koraganji over 3 years ago in reply to Jaya Shree C P

TI__Mastermind 19250 points

Hi Jaya Shree,

LED_LINK, LED_SPEED have inverted polarity on DP83848 by default (i.e., high voltage for off and low voltage for on). The reason behind this is explained in section 6.3.3.1 of the datasheet.

You can remove the inverters in between and check.

--
Regards,
Gokul.

+1 Jaya Shree C P over 2 years ago in reply to Gokul Koraganji

Prodigy 40 points

Hi Gokul,

Thanks for your inputs. Communication issue was resolved now.

Issues was due to missing of connections in power feedback circuit (Pins 16, 19 & 30). These 3 pins need to be shorted as per data sheet. But we missed it.

So, we shorted the pins and tested. Now it’s working fine.

0 Gokul Koraganji over 2 years ago in reply to Jaya Shree C P

TI__Mastermind 19250 points

Hi Jaya Shree,

Thanks for the confirmation. Please let me know if you need any other help.

--
Regards,
Gokul.

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DP83848J: DP83848J-Communication Issue between PHY IC and RJ 45 Jack