I'm creating a backplane for distributed control. The slave modules on the backplane will be using the Intel MAX10 FPGA. The main control will be a Xlinx Zync UltraScale SOC. The backplane communication will be MLVDS (BLVDS). When setting up the BLVDS on the MAX10, the VCCIO is automatically set to 2.5V and can't be changed. The Xlinx Zync UltraScale SOC MLVDS VCCIO is 1.8V only. The Xlinx Zync UltraScale SOC can receive the 2.5V based MAX10 BLVDS output signal. However, the Xlinx Zync UltraScale SOC can only transmit with a 1.8V based MLVDS. Can I directly connect the two together or do I have to have some sort of translation IC between them? Will the 1.8V based MLVDS signal of the Xlinx Zync UltraScale SOC meet the input requirements of the MAX10 BLVDS receiver?
In addition, the MAX® 10 FPGA Device Datasheet does not specify the output differential voltage swing or the output offset voltage (pg. 24). Note 23 (pg. 25) says, "No fixed VIN , VOD , and VOS specifications for Bus LVDS (BLVDS). They are dependent on the system topology.". I'm not sure what this means. Please explain in more detail or with an example. Thank you for you time.
Sorry for the late response.
In my opinion, using a level shifter is definitely a better option.
From what I understand from the BLVDS (TIA/EIA-899) standard receiver spec, this standard has an improved threshold. So, I think it should be possible to connect both the devices directly, as long as the transmitter drives output according to the receiver spec in standard. However, please consider the electrical aspects of it. I am not an expert in that, so would recommend you to run IBIS simulations before you do direct connections.
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