Forum Discussion
Arria 10 LVDS transmitter IP Core needs more documentation
- 6 years ago
Hi ,
I understand the below pointer. I would try to change the documentation as per the below feed back. But as an expectation, I cannot guarantee you the changes
Firstly, you need to tell the IP core whether the 'TX core registers clock' input is tx_coreclock or inclock, despite the fact that it's actually ext_coreclock (since we have an 'external' PLL). So you'd assume that the selection wasn't necessary, but changing the option appears to affect the SDC timings that are generated.
Secondly, you have to tell the IP core the 'Desired inclock frequency' for the PLL that's feeding the LVDS serializer. Again, this makes no sense as the only clock inputs into the LVDS serializer are at 100MHz (bar the fclk) and therefore have no relation to that PLL reference clock - since the PLL is 'external' to the LVDS serializer.
As a general comment, Personally I find the Altera/Intel documentation hard going. It would really help if there were some more block diagrams. I recently used the ALTLVDS on the Cyclone II. The circuit didn't work. Finally I got it working by reversing the data inputs. The code was ported from a competitors FPGA. I read the ALTLVDS documentation several times, there are lots of words, but at least for me a lack of clarity and lack of nice block diagrams.