Question on Urukul board status reading

LQF

Hello,
I met a problem of pll lock fail in one urukul board, that is the front panel red led is on and the frequency output is 160MHz while my setting is 100MHz. Then I would like to check the pll lock status by sta_read() function in urukul cpld class. However, the return shows all 0. How can I get the correct data?
Here is my code.

from artiq.experiment import *
from artiq.coredevice.urukul import urukul_sta_pll_lock, urukul_sta_smp_err
class UrukulPLLCheck(EnvExperiment):
    def build(self):
        self.setattr_device("core")
        self.setattr_device("suservo0")
        self.setattr_device("urukul0_cpld")


    @kernel
    def read_sta_once(self) -> TInt32:
        
        self.core.reset()
        self.core.break_realtime()
        delay(200*us)

        # Initialize CPLD (reads proto rev, sets up SPI) and give it a moment
        self.suservo0.init()
        delay(200*us)
        self.suservo0.cplds[0].set_att(0, 0.0)

        sta = self.suservo0.cplds[0].sta_read()
        
        #sta = self.urukul0_cpld.sta_read()
        return sta

    def run(self):
        sta = self.read_sta_once()

        pll_mask = urukul_sta_pll_lock(sta)   
        smp_mask = urukul_sta_smp_err(sta)    

        print(sta, pll_mask, smp_mask)

occheung

LQF However, the return shows all 0. How can I get the correct data?

You currently can't.
See gateware docstrings. On SU-Servo mode, EEM0[2] acts as NU_CLK, not MISO.
So your comments regarding the self.suservo0.init() line is wrong. Those inits are blind inits.
And since there are no MISO line available to SU-Servo, all CPLD and DDS read will not work.

ARTIQ PR #2875 will fix it, with a gateware patch.

LQF

occheung
Thank you so much! I got it! Is there any other way to check the PLL status? I have two DDS boards, when using the 125MHz clock from Kasli MMCX port, one is locked outputting the same frequency as setting and the other one is not locked with red led on, which output frequency larger than setting. When I use external trigger on both DDS boards directly from front panel SMA port, they all work well.

dpn

occheung

This is indeed a limitation of the current Urukul CPLD setup. If you need a solution without waiting for the other ProtoRev9 changes to come down the pipe, you could also use the firmware we developed in Oxford some years ago to operate SUServo phase-coherently (for which we also need to read back the status register): https://github.com/quartiq/urukul/pull/11 It will similarly require reflashing the cards and fiddling a bit with things on the ARTIQ side, though. (The code is public; see https://github.com/m-labs/artiq/tree/master/experimental-features that the above PR is loosely based on.)

LQF

Thank you so much! I got it! Is there any other way to check the PLL status? I have two DDS boards, when using the 125MHz clock from Kasli MMCX port, one is locked outputting the same frequency as setting and the other one is not locked with red led on, which output frequency larger than setting. When I use external trigger on both DDS boards directly from front panel SMA port, they all work well.

occheung

LQF Is there any other way to check the PLL status?

The red LEDs on the Urukul front panels is the only other way I am aware of. I am sure you have already been looking at them.

LQF When I use external trigger on both DDS boards directly from front panel SMA port, they all work well.

I assume you mean the "EXT CLK IN" SMA port on both Urukul 4410, where you supply an external clock to both cards.

Did you check the MMCX connection (and the corresponding clock signal) from Kasli to the problematic Urukul card?

LQF

occheung
Yes, it is the "EXT CLK IN" port.
I have checked the MMCX cable. There are four ports in my Kasli card and I use three of them. So I connect the remaining one out to the spectrum analyzer, the 125MHz is correct and the amplitude is correct as the Paweł Piotr Kulik master thesis mentioned.
However, those MMCX cables connected between the Kasli card and the Urukul card are hard to plug out, so I have not checked the other ports. I am afraid of breaking the cables and connectors. The space between two cards is small for plugging out the cable and the connector is tight.
Do you have any trick to check them safely?
Thank you so much!