Stratix3 Dev Kit, Using HSMC ports as I/O

Hi, Guys,

I've been experiencing I/O problems of the port for about a month but still have no clue of solving it.

First, I got a DVI RX/TX d-card, manufactured by Terasic (http://www.terasic.com.tw/cgi-bin/page/archive.pl?language=english&categoryno=68&no=359). I hooked up the card and download the loopback demo made by Terasic. With SignalTapII, I found the pixel clock signal can be recognized by the FPGA chip but can not be used to trigger any internal register of the chip.

Then, I powered on a VGA decoder/digitizer and connect the pixel clock to each of the 40 pins on a HSMC Debug Breakout Header d-card, which is an accessory card in the kit. The result is interesting:

For some pins, I can observe the input clock waveform in SignalTapII and can use the clock to trigger internal registers of the device;

For some other pins, the clock waveform is observable but can not bu use as triggering clock of device register;

For the rest of the pins, clock waveform is not even observable, I got constant 0 or 1 in the SignalTapII.

I'll attach my result along with schematic of both of the d-card I mentioned.

So...does any one know the reason of this problem or any suggestion of work around?

Any help is appreciated, thanks!

Best,

https://www.alteraforum.com/forum/attachment.php?attachmentid=1959

https://www.alteraforum.com/forum/attachment.php?attachmentid=1960

https://www.alteraforum.com/forum/attachment.php?attachmentid=1961