Using IMXRT EMC pins for Ethernet2 and Hyperram

[patriciocohen]

Hi guys,

I will appreciate you to answer these questions

1) Can I use the Ethernet2 interface without using the Ethernet1 interface?

2) Since I'm connecting a hyperram to the FLEXSPI2 interface in the same EMC domain, I think I will have to power this domain with 1.8v. Is this correct?

3) Since the EMC domain is going to be powered with 1.8v due to the hyperram, the Ethernet2 signals will have 1.8v levels. Im using the same PHY as the EVK1060 which is the KSZ8081. Will it work if I power the VCCIO pin in the PHY with 1.8v and leave the other things the same as the evk?

4) Why the KSZ8081 has 49.9 ohm resistors connected to VCC on the RX and TX pairs in the EVK1060? The datasheet states that it has internal terminations, and that external ones are not required.

Thank you,

Patricio

[jeremyzhou · Accepted solution]

Thank you for your interest in NXP Semiconductor products and for the opportunity to serve you.
1) Can I use the Ethernet2 interface without using the Ethernet1 interface?
-- Yes.
2) Since I'm connecting a hyperram to the FLEXSPI2 interface in the same EMC domain, I think I will have to power this domain with 1.8v. Is this correct?
-- Yes.
3) Since the EMC domain is going to be powered with 1.8v due to the hyperram, the Ethernet2 signals will have 1.8v levels. Im using the same PHY as the EVK1060 which is the KSZ8081. Will it work if I power the VCCIO pin in the PHY with 1.8v and leave the other things the same as the evk?
-- Yes.
4) Why the KSZ8081 has 49.9 ohm resistors connected to VCC on the RX and TX pairs in the EVK1060? The datasheet states that it has internal terminations, and that external ones are not required.
-- In my experience, it usually adds these resistors to achieve resistance matching, they can be removed which depends on you.

Have a great day,
TIC

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[patriciocohen]

Hi Jeremy,

Thank you very much.

Have a nice day!

Patricio