Topic: FMC125 DMUX 1:1 Mode?  (Read 4445 times)

jchang August 06, 2013, 12:04 PM

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I have the FMC125 running on a ML605.

The FMC12x User Manual pg. 7 (October 2012) states:
"The FMC122/FMC125 has a 1:2 DMUX feature. In 1:2 DMUX mode eight 8-bit LVDS busses run at a maximum of 625Mbps each.
The FMC126 does not offer a DMUX mode and has four 10-bit busses running at a maximum of 1.25Gbps each."
"It should be noted that successful implementation of LVDS connections running at 1.25Gbps (FMC126) highly depends on carrier board design and layout."

Also, I see DMUX_MODE generic in ev8aq160_quad_phy.vhd, which leads me to ask:
1) Does the FMC125 support 1:1 DMUX mode?  If not, why?
2) Does the ML605 support the LVDS 1.25Gbps that the 1:1 DMUX mode requires?  I would think it would have to, since the ML605 is compatible with the FMC126 which only runs at 1:1 DMUX mode/LVDS 1.25 Gbps.  If that's the case, why doesn't the FMC125 run in 1:1 DMUX mode?
3) If so, to enable it, is it as simple as changing the DMUX_MODE generic to 1?

Thanks in advance.

Kyu August 08, 2013, 02:05 PM (#1)

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For the hardware point of view, FMC125 supports the 1:1 DMUX mode. Because of the FPGA speed, we generated the firwmare for 1:2 DMUX mode. 1:1 DMUX mode for FMc125 is not tested recently. It should work, but I cannot confirm it. In order to use it, DMUX mode and clock constraints in the firmware and clock/adc settings in the software needs to be updated.