i.MX8M mini ENET IO voltage

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i.MX8M mini ENET IO voltage

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shruthi_subrama
Contributor I

Hi

As per i.MX8M Mini Datasheet NVCC_ENET supports 1.8V/2.5V/3.3V IO voltage.According to Ethernet PHY (AR8031) used in i.MX8M Mini EVK board, MDC,MDIO are 3.3V only tolerant and  in EVK ENET IO (NVCC_ENET) voltage is set to 1.8V (used Voltage Translators for MDC,MDIO pins).

Is there any limitation or issue when we set ENET IO(NVCC_ENET) voltage  to 3.3V ?

We want to set  NVCC_ENET to 3.3V to avoid Voltage Translator on MDC,MDIO pins with the same Ethernet PHY in our Custom design using i.MX8M Mini &  Nano CPU.

Best Regards,

Shruthi Subramanian

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rfguy1
Contributor I

Igor,

For the DART-MX8M-MINI, the datasheet (J1.31-No EC of Table 3) shows the voltages for RMII, RGMII, and GPIO.  What is the voltage(s) NVCC_ENET for MII (using 4 lines for ENET_RDx and 4 lines for ENET_TDx)?

Regards,

Erik

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1,221 Views
shruthi_subrama
Contributor I

Hi igor,

Thanks for the reply.I would also like to know as per i.MX8MM Errata "e50080" -

(IO internal pull up/down is not supported in 3.3V mode.For 3.3V IO operation use external resistors for pull up/ pull down and disable the internal pullup/down via software.All IO pin groups are impacted except for XTAL, DDR, PCI, USB, and MIPI PHY IO’s.) whether we need to give External Pullup Resistor Option or not  for i.MX8MM all ENET IO signals at CPU side if we are setting NVCC_ENET to 3.3V.

Regards,

Shruthi

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1,221 Views
igorpadykov
NXP Employee
NXP Employee

Hi Shruthi

according to Table 64. i.MX 8M Mini 14 x 14 mm functional contact assignments

Datasheet MDC,MDIO pins also belong to NVCC_ENET power group.

From i.MX8MM side there are no restrictions for using 3.3V, if phy allows

this voltage also can be used. Setting NVCC_ENET to 3.3V means that all i.MX8MM

enet signals will operate with I/O 3.3V levels.

Best regards
igor
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1,220 Views
shruthi_subrama
Contributor I

    Hi igor,

   Thanks for the reply.I would also like to know as per i.MX8MM Errata

"e50080" -

   (IO internal pull up/down is not supported in 3.3V mode.For 3.3V IO

operation use external resistors for pull up/ pull down and disable the

internal pullup/down via software.

All IO pin groups are impacted except for XTAL, DDR, PCI, USB, and MIPI

PHY IO’s.) whether we need to give External Pullup Resistor Option or

not  fori.MX8MM all ENET IO signals at CPU side if we are setting

NVCC_ENET to 3.3V.

I  If Pull up resistor is needed for 3.3V IO ENET, how much is

recommended Pullup value for ENET Signals?

Regards,

Shruthi

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igorpadykov
NXP Employee
NXP Employee

Hi Shruthi

for external pulls one can use the same values as internal.

Best regards
igor

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