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Altera_Forum
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13 years ago

Nios II interfering with VGA Data

Hi! I'm trying to implement a Nios II core to manage an RS232 link on a Cyclone IV embedded in a DE2-115 board. On the same FPGA, but unrelated to the Nios II, is a VGA controller writing data...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
13 years ago

Is it just random pixels corrupted or does your output not work? If it's just a few bits here and there I would suspect it could be noise on the board causing this or a timing issue. Here is what I would do to tackle this:

1) Make sure you have timing constraints, if you don't then all bets are off and you probably just got lucky the VGA only design worked.

2) Remove the VGA portion of the design and make sure the Nios II portion actually works properly on it's own.

3) Look at the pin locations of the VGA interface and see if there are other interfaces you are using nearby and start to try to narrow the problem down to potential noise issues like crosstalk.