How to interface a phy device with another phy (BCM5482 --IC175C)?

[sureshte007]

Hi
can any one tell me how to interface a phy device with another phy (BCM5482 --IC175C).

 

[FvM]

phy to phy

I think, neither the RGMII data interface nor the managment interface is suited for PHY back-to-back connection. You would need a custom designed glue logic, e. g. from a CPLD. Also most likely a configuration must be supplied to the PHYs through the managment interface.

 

[sureshte007]

rgmii back to back

its not like that actually if we want to interface a phy with a mac means we will use a transformer in between in the same to interface PHY to PHY i got one refrence in that refrence they had mentioned to add a capacitor between each signal of 10 Uf.
and i had done that but it is working for only IC175C .and not with BCM5482.so how to solve this issue.

 

[dennis zhang]

Re: phy to phy interface

Hi,
I know what you want, a transformerless application, right?
You mean IC175C can hear from BCM5482, but BCM can not hear IC175, is it? Normally, transformerless application is only applicable to the both PHY from same vendor, to be excatly, the same Partnumber. I guess there is some mismatch between the differential pairs of both side. Or you need a DC bias for either side.
By the way, you also need consider the Auotnego when debugging. If both side support Fiber mode, maybe you can try this mode.

 

[FvM]

phy to phy interface

So you want to connect the network sides. Having specified termination resistors at each side and capacitive coupling will work in most cases, some transmitters need a transformer for driver biasing, but you can use two individual inductors instead.

 

[sureshte007]

Re: phy to phy interface

Hi

AC coupling is working well and good if i check the two ports of IP175C and individually both the ports of both the devices are ok they are respopnding but when i tried to interface both these with some termination resistor circuit in parallel between the pair of signals and coupling capacitor of 10Uf is not working ,but the same circuit is working if both the devices are of same make.

So can u suggest what else to be done to make it work without adding transformer ckts on both the devices