Honored Contributorhi all,
i am designing a board using stratix II FPGA (EP2S15F484C3).. I want to know whether this FPGA has the inbuilt lvds transmitter and receiver or i have to use external lvds transmitter and receiver ICs. please help me... regards Asha
Honored ContributorIt has internal transmitters. Higher data rates can be achieved only with internal LVDS interface, also you can expect higher immunity against on-board generated interferences. If external transmitters/receivers are required for some reason, you should use differential LVDS repeater chips rather than interfacing the FPGA singled-ended.
You should pay attention however to the I/O-voltage and pin placement requirements when using LVDS. The Quartus Pin Planner helps to keep all constraints.Honored Contributorhi...
thanks for the reply.... ya, i will take care of the I/O-voltage and pin placement requirements for using LVDS. i want to know, if i want to use the LVDS transmitter and receiver inbuilt in FPGA, how do i instantiate them. Is there any megafunction available or how it is done?Honored ContributorNormally, you instantiate a LVDS transmitter or receiver by assigning LVDSI/O standard to a single ended port pin with an optional DIFFIO_xxp function. The inverted DIFFIO_xxn is then selected by the Quartus fitter automaticly. There's are also differential I/O low-level primitives, but they are rarely required in standard designs.
Honored Contributorhi.... thanks for the reply
"you instantiate a LVDS transmitter or receiver by assigning LVDSI/O standard to a single ended port pin with an optional DIFFIO_xxp function" This means in the pin assignment editor we just have to change the I/O standard.... we need not have to instantiate the altlvds receiver/ transmitter megafunction.Honored ContributorThe LVDS Megafunction is providing the serializer/deserializer. In most applications of LVDS I/O standard, it will be used. But it's not required to use the I/O standard.
