09-01-2019 07:40 PM
I'm using ZU4EG SFCV784 pkg.
I'm planning to use 1GE phy, and going to connect to GTH port.
(I know I don't need to use GTH.. anyway)
Design structure is RJ45 <-> T/F <-> PHY <-> GTH and PS MIO BANK.
So i should connect single-ended TX 4 port and RX 4 port to GTH, but i don't know how to configure it.
First of all, I connected MGTHRXPO, P1, P2, P3 to RX 4 port of PHY, and MGTHTXP0, P1, P2, P3 to TX 4 port of PHY.
And I connected MGTAVTTRCAL_R to VCCO_HP and MGTRREEF_R connected to VCCO_HP with serial resistor.
The other control signals of PHY are connected to PS MIO.
My questionare is as below.
1. Is there anything wrong with the foregoing?
2. In case single-ended I/O connect to GTH, how should I handle of N0, N1, N2, N3 of TX, RX?
09-04-2019 11:46 PM
09-04-2019 03:16 AM
Hi @torresuarez ,
GTH inputs/outputs are differential and you should use them this way. The RJ45 connector has differential signals too, I would say. Where do you find single-ended signals here? Do they come from your PHY? What are you using there?
To use the transceivers you need to provide them with their own supplies. You should not connect to other IO supplies like VCCO. Please refer to the Board Design Guidelines in UG576.
09-04-2019 03:45 AM
@torresuarez The GTH (and all of the GT* transceivers) cannot operate in single-ended mode. Unlike the general-purpose SelectIO pins, the transceivers support exactly one I/O standard, which is a CML differential signalling system. If your PHY requires single-ended signals, route those to SelectIO pins instead.
09-04-2019 03:53 AM
Is this a PHY not in the FPGA ?
Which PHY is it ?
Most ( ALL ) the phys I know use an interface to the FPGA thats differential, such as the SGMII ,
09-04-2019 05:07 PM - edited 09-04-2019 05:10 PM
Thank you for your reply.
I use PHY of RGMII interface, so TX, RX are not differential.
So I connected TX 4bit to TXP0~TXP3 of GTH Bank, and RX 4bit to RXP0~RXP3 of GTH Bank.
But GTH port should only use differential signal, is it impossible to connect to TX, RX to GTH port?
09-04-2019 11:46 PM
09-05-2019 07:20 AM
@torresuarez No, the GTH cannot drive these lines in single-ended mode. It can't meet the speed requirements either - the minimum speed for a GTH is 500Mbps and RGMII needs to operate right down to 2.5Mbps.
Quite apart from that, all the high-speed transceivers are pretty power-hungry - best not to use them unless you need that performance.