I/O standard for ZCU208 CLK104_SFP_REC_CLK_P

[norume]

I want to drive a CLK104 card from the FPFA CLK104_SFP_REC_CLK_P/N lines.  What I/O standard is appropriate for this?  I tried LVDS, but that's not a valid option for these pins.

[markg@prosensing.com]

@norume 

From the ZCU208_master.xdc, I find:

set_property PACKAGE_PIN L21      [get_ports "CLK104_SFP_REC_CLK_N"] ;# Bank  67 VCCO - VADJ_FMC - IO_L3N_T0L_N5_AD15N_67
set_property IOSTANDARD  LVDS     [get_ports "CLK104_SFP_REC_CLK_N"] ;# Bank  67 VCCO - VADJ_FMC - IO_L3N_T0L_N5_AD15N_67
set_property PACKAGE_PIN M20      [get_ports "CLK104_SFP_REC_CLK_P"] ;# Bank  67 VCCO - VADJ_FMC - IO_L3P_T0L_N4_AD15P_67
set_property IOSTANDARD  LVDS     [get_ports "CLK104_SFP_REC_CLK_P"] ;# Bank  67 VCCO - VADJ_FMC - IO_L3P_T0L_N4_AD15P_67

Also, from Table 6 in UG1410(v1.0), I find that Bank 67 is an HP bank with VCCO typically set to 1.8V.  So, CLK104_SFP_REC_CLK_P and CLK104_SFP_REC_CLK_N on the ZCU208 can receive or send LVDS.

What is telling you that LVDS is not a valid option for these pins?

Cheers,
Mark

[norume]

My mistake in the original message.  Copy/pasted the wrong content.

The signals I'm interested in are the CLK104_PL_CLK and CLK104_PL_SYSREF coming back from the CLK104 card.  These are on pins B7, B8, B9 and B10 (Bank 87).  This is also a 1.8V bank, but if I specify LVDS I get errors stating that LVDS is not supported for banks of High Density.

The CLK104_PL_CLK and CLK104_PL_SYSREF  are needed for multi-tile synchronization.

[markg@prosensing.com]

@norume 

Bank 87 of the ZU48DR on your board is an HD (not HP) bank.  As shown in Chapter 3 of UG571(v1.12), HD banks support LVDS input (but not LVDS output) and only with an external termination.

[norume]

I see what I need to change.  I had specified LVDS, when I should have specified LVDS_25.

This seems incorrect to me given that the bank supply is actually 1.8V.  But I don't see LVDS_18 as an option.

 I now have the following which results in a successful synthesis and implementation:

set_property PACKAGE_PIN B10 [get_ports CLK104_PL_SYSREF_P]
set_property PACKAGE_PIN B9 [get_ports CLK104_PL_SYSREF_N]
set_property IOSTANDARD LVDS_25 [get_ports CLK104_PL_SYSREF_P]
set_property IOSTANDARD LVDS_25 [get_ports CLK104_PL_SYSREF_N]
set_property PACKAGE_PIN B8 [get_ports CLK104_PL_CLK_P]
set_property PACKAGE_PIN B7 [get_ports CLK104_PL_CLK_N]
set_property IOSTANDARD LVDS_25 [get_ports CLK104_PL_CLK_P]
set_property IOSTANDARD LVDS_25 [get_ports CLK104_PL_CLK_N]
create_clock -period 87.931 [get_ports CLK104_PL_CLK_P]
create_clock -period 175.862 [get_ports CLK104_PL_SYSREF_P]