DP83849IF Strap Options

Sebastian Miesner

Other Parts Discussed in Thread: DP83849IF

I am using the DP83849IF Dual-Phy and want to use the Strap Options for automatic configuration during start-up. I am using actually an microblaze prozessor to set the register using the MDIO interface.

First I readout the actual register status and then I set the register and read out the register status again.

I can see that using the strap options nearly everything is alreight but in register 4 bit 7 (100BASE TX-Support) is 0 instead of 1. I have tested several strap options to set these bit to 1 but I have no idea which strap option I have to use.

I can´t find in datasheet an table with the corresponding strap options to a register.

If anyone now how to do this, please help.

over 10 years ago

0 Patrick OFarrell over 10 years ago

TI__Mastermind 31600 points

100Base-TX half-duplex is not supported in extender mode. Please check bits 10:9 of the RMII and Bypass Register (RBR), addresses 17h, to confirm the strap configuration for extender mode.

Patrick

0 Sebastian Miesner over 10 years ago in reply to Patrick OFarrell

Prodigy 50 points

Hello Patrick,
I am using the Phy in RMII Mode without FX-Mode. I have disabled the extender mode (register 17h, bit 10:9 to '0') and I want to use 100Base-TX Full duplex mode not half-duplex.
I have set in (ANAR)-Register Adress 04h, bit 8,bit 7 to '1' and bit 6 and bit 5 to '0'.
I can set register 4h, bit 7 to '1' by using MDIO interface, but I want to use the strap options for that.
I´m not quite sure if I need that bit 7, my configuration is to use fixed 100 Base tx/ rx full duplex mode.

thanks for your valuable replay,

Sebastian Miesner

0 Patrick OFarrell over 10 years ago in reply to Sebastian Miesner

TI__Mastermind 31600 points

Sebastian,

Extender mode can be disabled by strap. You just need to make sure that the RXD2_B pin is pulled low during power up and/or reset.

Patrick

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DP83849IF Strap Options