Bitfile or help – Mesa 6i25 + 7i74 (BiSS-C) + 8i20 + 7i70/7i87

i am not making any progress so let take a step back.
i use a bit file PIN_7I76_7I74BISS3D_34 With the biss signal assigned to a 7i74 plugged on the port P2 with the pin configuration :
        IOPortTag & x"00" & BISSTag  & BISSDataPin,             -- I/O 17    PIN 1
        IOPortTag & x"01" & BISSTag  & BISSDataPin,             -- I/O 18    PIN 14
        IOPortTag & x"02" & BISSTag  & BISSDataPin,             -- I/O 19    PIN 2
        IOPortTag & x"00" & NullTag & x"00",                    -- I/O 20    PIN 15
        IOPortTag & x"00" & BISSTag  & BISSClkPin,            -- I/O 21    PIN 3
        IOPortTag & x"01" & BISSTag  & BISSClkPin,            -- I/O 22    PIN 16
        IOPortTag & x"02" & BISSTag  & BISSClkPin,            -- I/O 23    PIN 4
I dont understand yet why we have 3 pin for data and 3 for clock but its fine.

the objective now is to get the system to produce at least a clock. with the cnc project running i tried to locate where the clock where available but nothing. I tested each port rj45 on my 7i74 and even the pin from the cable between my two card and nothing relevant. i got power (5v) some signal but no clock. do i need a command in hal/init /bit/god? to indicate that the signal should be active?

i found it i got my clock.
i needed this two line:
setp hm2_5i25.0.biss.00.timer-number 1
setp hm2_5i25.0.biss.00.frequency-khz 8000.
i just want to know if it is ok to have 10 volt of amplitude between -5 clk- and +5 clk+ with spike to -10 +10 v? seem a bit much for a clock, WIll test other cable i may have made a mistake here.

There are 3 clocks because there are 3 BISS channels in that configuration

in addition you mast set the DPLL timer so that the BISS read completes before the nominal read time
something like:

setp hm2_5i25.0.dpll.01.timer-us -200

The 7I74 only outputs 5V signals so no 10V signal is possible other than
perhaps overshoot on an unterminated line.

The outputs swing from ground to +5V, so If you measure between
outputs, you could read +5V or -5V depending on the output state.