DP83826E: Wake up function

Hi Fabio!

Yes, LED2 & LED3 (only available if using RMII) can be configured to output HIGH using extended Registers 0x305 & 0x306. This requires register configuration. 

Section 9.3.17 of the data sheet has more information.

Regards,

Alvaro

My customer used TMS320F28P65+2*DP83826+DC-DC scheme with EN solutions now,

They want to achieve low power consumption at<1mA level?

How to achieve sleep and wake-up to achieve this goal?

It seems in low power mode, the power consumption is still very large.

Hi Fabio,

Like you see in the data sheet, IEEE Power Down will be the lowest power consumption mode. Could you help me understand where the customer's <1mA requirement comes from?

IEEE Power Down can be controlled in two ways:

• by asserting a low signal on Pin 21 - PWRDN
• by writing to Register 0x0[11] = '1'

The MCU will have to control when the DP83826 goes into a low power mode, note that when in IEEE Power Down, no packets will be received via the ethernet cable.

Regards,

Alvaro

" Yes, LED2 & LED3 (only available if using RMII) can be configured to output HIGH using extended Registers 0x305 & 0x306. This requires register configuration.  Section 9.3.17 of the data sheet has more information."

The customer will use DP83826 in enhanced mode.

Why only available in RMII mode? I did not find the description in datasheet.

According to the description,

"In MII mode this pin is asserted high when the receive or transmit medium is non-idle. Carrier
sense and receive data valid."

It seems it also could output high when there is communication in MII mode? I am confused.

More two questions:

1. Is there a range value for impedance control of our Ethernet PHY DP83826, such as 50ohm, 100ohm, etc?

2. Is there a specific tolerance requirement for the equal length of signal lines?

Hi Fabio,

Alvaro is currently out of office. He will provide an response by tomorrow. Thank you for your patience

--

Regards,

Hillman Lin

Hi Fabio,

Thank you for your patience.

LED2 and LED3 are only available in RMII mode, because in MII those pins are used for communication (COL and CRS). However, COL and CRS are only needed in MII when communicating in Half Duplex. If your application will always be full duplex, then these can be configured as LED's as well.

Fabio Gou said:

1. Is there a range value for impedance control of our Ethernet PHY DP83826, such as 50ohm, 100ohm, etc?

2. Is there a specific tolerance requirement for the equal length of signal lines?

Yes there are! These can be found in our Industrial Layout checklist, found in the Design Tools & Simulation tab of the DP83822 Product Page

Regards,

Alvaro