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AR# 15440

CORE Generator Gigabit Ethernet MAC v2.1 - The UCF file must be modified for GMII configuration of the core when it is targeted to a Virtex-II Pro device

Description

Keywords: Virtex-II Pro, V2Pro, GEMAC

Urgency: Standard

General Description:
The GMII configuration of the Gigabit Ethernet MAC (GEMAC) requires that the SelectI/O be set to 3.3V TTL. 3.3V TTL is the default for the other device families supported by this core, but if the GMII configuration of the GEMAC is targeted to the Virtex-II Pro family, the default SelectI/O setting of 2.5V CMOS for Virtex-II Pro must be explicitly forced to 3.3V TTL to meet the GMII requirement.

Solution

You can force the SelectI/O to be 3.3V TTL via the UCF file.

Add the following lines (Note that there is no order dependency in a UCF file, so these lines may be inserted anywhere in the UCF):

# GMII SelectIO standard: please do not edit
INST *gmii_rxd* IOSTANDARD = LVDCI_33;
INST *gmii_rx_dv IOSTANDARD = LVDCI_33;
INST *gmii_rx_er IOSTANDARD = LVDCI_33;
INST *gmii_rx_clk IOSTANDARD = LVDCI_33;
INST *gmii_txd* IOSTANDARD = LVDCI_33;
INST *gmii_tx_en IOSTANDARD = LVDCI_33;
INST *gmii_tx_er IOSTANDARD = LVDCI_33;
INST *gmii_col IOSTANDARD = LVDCI_33;
INST *gmii_crs IOSTANDARD = LVDCI_33;
INST *gmii_tx_clk IOSTANDARD = LVDCI_33;


For more information about the LVDCI_33 setting in the Virtex-II Pro devices and which I/O banks of the Virtex-II Pro may be used at 3.3V, please refer to (Xilinx Answer 14965).
AR# 15440
Date Created 08/20/2002
Last Updated 11/07/2004
Status Archive
Type General Article