dp83640 register configuration in fiber mode

Naeem,

I believe this post is a duplicate of another post:

http://e2e.ti.com/support/interface/ethernet/f/903/t/382554.aspx

Could you confirm this?  If this is correct, would you mind if I delete this post and use the other post for any additional inquiries?

Patrick

Hi Naeem,

Here is how you can enable fiber mode.

Fiber mode enable with Strapping:

1. Use 2.2Kohm pull-down resistor on the RX_ER (FX_EN_Z) Pin.

          -This will force it into fiber mode

2. Use AN0 strap (pin LED_ACT) to decide between full or half duplex operation.

          - For full duplex (no external Pull-Up needed)

          - For half duplex (use a 2.2Kohm Pull-Down resistor)

Fiber mode enable with Register Writes:

1. Set FX_EN bit

           - Write a "1" to Bit[6] in Register PCSR (PCS Configuration and Status Register) 0x0016

2. Set for Full-Duplex Operation

           - Write a "1" to Bit[8] in Register BMCR (Basic Mode Control Register) 0x0000

3. Set for Half-Duplex Operation

           - Write a "1" to Bit[8] in Register BMCR (Basic Mode Control Register) 0x0000

Regards,

Ross

okk.. I am not getting how to write in these registers in practical... i.e., how to configure these registers in practical..?? do i have to use some software or by hardware means the registers can be configured..??

Hi Naeem,

There is a section in our datasheet dedicated to the serial interface (MDIO) that is used to read and write to the PHY registers.

Your CPU/MPU or controller will need to have the MDIO interface to communicate.

If this is not possible, it is highly recommended that you use a hardware means of setting the registers.

Hardware configuration is done by strapping.

When the phy is powered on or there is a hard reset, the voltage read on certain pins of the chip will be stored (latched) and set the PHY registers. The pins with this strapping option are labeled in the DP83640 datasheet (section 3).

In this section you will see that there are 2 pins required for hardware setting fiber mode.

These pins are AN0 (LED_ACT) and FX_EN_Z (RX_ER).

RX_ER has an internal weak Pull-Up resistor that disables Fiber mode. To force the PHY into fiber mode you will need to have a 2.2Kohm resistor connected from the RX_ER pin to GND.

LED_ACT has an internal weak Pull-Up resistor that forces the PHY into full-duplex operation. If you require a half-duplex operation you will need to connect a 2.2Kohm resistor from the LED_ACT pin to GND (Pull-Down).

Hopefully this was clear.

Regards,

Ross

Thank you so much..

what about other registers..?? are they need to be configured or it is not necessary..??

Also i would like to know about PTP time synchronization.. how it should be done..?

I am interfacing wiznet 5300 chip with this PHY, which is further interfaced to optical transceiver...

Hi Naeem,

In section 3 there are other functions that can be controlled by using the hardware setting (strapping) that I described above.

For registers that are not listed in the strapping section you will need to use MDIO serial interface to communicate with the PHY.

What is your end goal for this application? 

Please create a new form thread for questions on PTP. This allows maximum viability so that other people can search for it.

Regards,

Ross

okk.. my end goal of application is Board to board communication via fiber optic cable, the flow is like this as below:

FPGA->wiznet 5300->PHY->optical transceiver

on the other side same flow..

There are no other registers required (besides the fiber ones mentioned above) for fiber operation.

Regards,

Ross 

Thank you so much.. if any problem occurs during implementation.. i will let you know...

Dear Sir,

I am also facing the issue of DP83640 not pinging in fiber mode.

I am using AM3354 processor and interfacing DP83640 chip over RMII mode. DP83640 is prefectly pinging while it is used in COPPER mode.

Hardware Strapping are as belows:

For Copper mode, LED_ACT (Pin 26), LED_SPEED(Pin 27), LED_LINK(Pin 28) are individually pull up using 2.2K resistor and RX_ER(Pin 41) is also pull up using 2.2K resistor. IN copper mode, DP83640 is pinging properly and link is also detected in linux console.

For Fiber mode, LED_ACT is pull up using 2.2k and RX_ER is Pull down using 2.2k while LED_SPEED and LED_LINK  pins are floating. We are using AFBR5803TZ fiber transceiver and SCto ST fiber multimode cable. But, we are not able to ping in fiber mode. Link is also not detected in linux console.

Please find below schematic of fiber optic connector. Please suggest the solution.

Hi,

These register provide information on the Link Status and Configuration of device. Refer to DS for details on these registers.

http://www.ti.com/lit/ds/snosay8f/snosay8f.pdf

THese have to be accessed thru MDIO/MDC interface. If your driver provide interface to read the registers, you can use this. 

Regards,
Geet