Hello!
I am developing with a MicroZed 7020, a FMC-CC and a ADC plugged in to the carrier card. My problem is this:
The FMC module is controlled with SPI, 1.8V signalling. The data from the module is sent over LVDS at 1.8V offset.
Both interfaces have signals going to both bank 34 and 35 on the Zynq.
Now, because these banks are HR (high-range, ironically) I cannot use the LVDS I/O standard (1.8V). However, I believe I can set the I/O standard to LVDS_25 while VCCIO is 1.8V for each bank, as long as DIFF_TERM is disabled. (UG497 p.100)
However, this means I have to have external differential termination.
So, my 2 questions:
1: What is the best way to provide such termination? Has AVnet provided any convenient sites to solder terminating resistors on either the MicroZed or FMC-CC?
2: Can I flip the problem around, i.e. specify 2.5V VCCIO, LVDS_25 and enable DIFF_TERM for the differential inputs, while the signal levels are physically 1.8V? Will the LVCMOS18 inputs still work? Could it damage anything?
Kind regards,
Snorre
