Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
14 years ago

Stratix IV GX Pin Assignment

Hi, I'm working on the Stratix IV GX 230 board and I'm trying to use the Triple Speed Ethernet in RGMII mode with MDIO. I did everything well untill the moment I needed the PIN in order to co...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
14 years ago

Does mdio_oen always stay at 1? That's strange, it should go to 0 when the TSE wants to read the PHY's answer. You should also se some toggling on mdio_out and the mdio pin.

I'm not sure how Quartus will understand and synthesize this: 

mdio_inout <= system_mdio_out when (system_mdio_oen = '0')
else 'Z' when (rising_edge(clk));
but it probably won't be what you expect. Just ule a regular buffer: 

mdio_inout <= system_mdio_out when (system_mdio_oen = '0')
else 'Z';
No need to take the clock into account here.