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Altera_Forum
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8 years ago

How can I make the Marvell 88E1111 operate in GMII instead of RGMII?

Hi, I've recently gotten the ETHERNET-HSMC Card for use with the Cyclone V GX Starter Kit. Problem: It uses RGMII by default, and I want GMII. The manual just says that this can be ch...
Altera_Forum's avatar
Altera_Forum
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8 years ago

There should be a ban on Marvel products for development kits, the lack of public documentation make then a pain to use.

The interface mode is set with the HWCFG_MODE[3:0] register. It should be 1111 for MII/GMII and 1011 for RGMII.

The initial value of HWCFG_MODE[3:0] value comes from the configuration pins. I haven't look at the PCB but I guess that you can't change that from the FPGA.

After power up you can change the mode by writing the new value of HWCFG_MODE[3:0] to bits 3:0 in register 27, and then perform a software reset. To perform a software reset, set the bit 15 of register 0 to 1. It will be cleared to 0 automatically when the reset operation is done.