Hi,

we want to run two instances of our little DRS DAQ program but obviously the first instance started always claims all DRS boards for itself and the other one exits with an error. The 2 boards used in the example below have the serial number # 2413 and #2414 and are v5 boards.

The first one:

mathes@ikauger5:~/src/DRS4/Cpp> ./drsdaq -b 2413
DRSController: found board with serial number #2413
DRSController: found board with serial number #2414
DRSController: using board with serial number #2413
CalibratedFrequency= 1.00721
====================================
DRS type:            DRS4
Board type:          9
Serial number:       2413
Firmware revision:   21260

...
And the second one:

mathes@ikauger5:~/src/DRS4/Cpp> ./drsdaq -b 2414
musb_open: usb_set_configuration() error -6
musb_open: Found USB device 0x04b4:0x1175 instance 0, but cannot initialize it: please check permissions on "/proc/bus/usb/1/7" and "/dev/bus/usb/1/7"
USB successfully scanned, but no boards found
...

How can our goal be achieved?

Thanks

Hermann-Josef

Hi, Stefan,

I found that my collaborator bought 2 older version of evaluation board before.
They are the version 1.2 in plastics case with firmware 13191.

Can I upgrade the firmware from 13191 to 13279?
I'm wondering if the older version of evaluation board is working with firmware 13279.

Thanks,
Heejong

 Hi, Stefan,

drs_exam.cpp is working good to read-out one board.

Now I would like to read-out two boards at the same time using the same trigger( external or internal).

I'm trying to understand and modify the original code for control two board.

Meantime, it would be very appreciated if you give any tips for this.

Thanks,

Heejong

Hello,

I'm using DRS4 evaluation board version4 in Linux (Scientific Linux 5).

Version4 software (drs-4.0.0) was installed without any troubles.

The oscilloscope interfrace program (drsosc) is working fine with version4 software.

But when I tried drs_exam program, it doesn't work as expected.

(500 mV positive (width 50ns)  pulse is connected to Ch#1).

It keeps waiting trigger in the first event.

In the previous version (board/software drs-3.0.0), drs_exam program worked well.

I'm wondering if anybody is using drs_exam with V4 evaluation board.

Any comments/help would be welcomed.

Thanks,

Heejong

Hello Stefan,

Thanks for your prompt reply.

drs_exam is working now after modification as above.

By some trials, I found that external trigger is possible by 'b->EnableTrigger(1,0); b->SetTriggerSource(1<<4);'

Best,

Heejong

Hi Stefan,

    I have an old-version DRS4 evaluation board which doesn't have the latest firmware. I tried to flash the drs_eval1.ipf boundary scan chain into the XCF02S PROM with Xilinx IMPACT, and the firmware seemed to go through into the PROM. However, when I started the DRS command line interface to test the firmware it kept on reporting errors like

musb_write: requested 10, wrote -116, errno 0 (No error)

musb_read error -116

musb_write: requested 10, wrote -22, error 0 (No error)

musb_read error -116

and so on. Finally the program made a dumb recognition of the board as

Found mezz. board 0 on USB, serial #0, firmware revision 0

Do you have any idea which caused this problem? Thanks!

Hi Stefan,

    in the latest DRS4 datasheet I only saw your data of the DRS4 PLL locking time for 6GSPS sampling speed, with other rows "TBD". Have you tried those lower frequencies? According to the datasheet I think the PLLLCK should be stabily low when the PLL is locked; am I right? However when I try my design with the DRS4 chip and feed the reference clock signal at 0.5MHz or 2MHz, the PLLLCK I get can never stabilize. There could be some problem in the PCB circuit connection, but I want to confirm with you since I'm confused with those "TBD" blanks.

    Thanks a lot!

Thanks! I see. The capacitor is important. However I'm a little confused... If PLLLCK=DTAP XOR REFCLK, shouldn't it integrate to low instead of high when the two clocks are in phase? I must have some misunderstanding here. So if we ignore any realistic complexity and assume DTAP is perfectly locked with REFCLK, will PLLLCK be always low or high? I'm sorry I do not know how the DRS internal PLL and its input/output work...

 Got it. Thank you! By the way I have another question: when the default operation mode of the DRS4 chip is used, i.e. WSRIN is fed internally to WSROUT, at the external pins is it necessary to leave the WSRIN open? Or any input through the pin will not affect the Domino wave running? Also I observe that WSROUT will be always low when the chip is running in this mode; is it the supposed behavior?

 Sorry; WSROUT also has an inverter? Actually I have one more stupid question about the shift registers: when we assert the address bits to operate on one shift register, e.g. WSR, we use SRIN to give input and SROUT to read output; but how does the shift register know whether we're reading or writing? Or it will just receive input from SRIN and give output at SROUT at the same time?

Thank you so much!

Hi Stefan,

    I read in the datasheet that every time after power up the Domino wave in DRS4 needs to be started and stopped once to initialize the Domino circuit. However in your firmware it seems the chip immediately goes into the idle state after reset. Is that Domino circuit initialization really necessary?

    Also an aside question: in your firmware the readout process has the SRCLK sent to DRS4 only about 200ns later after RSRLOAD gets asserted instead of immediately following RSRLOAD. Is there any reason for that?

    Thanks a lot!

Hi Stefan,

    thanks to your help I can now successfully keep the Domino wave running at a stable frequency and maintain the channel cascading information in the Write Shift Register. (Since you told me WSR always reads and writes at the same time, I think I need to rewrite the information back every time after reading out from WSR to decide from which channel my data come, don't I?)

    However I'm still having difficulty in reading out from the DRS cells. I use the ROI readout mode and assume as long as I give a pulse on RSRLOAD the data will come out one by one. However, what I get is just a constant with some noise, which seems I'm always reading from the same cell. Actually I'm not very clear about how it works. What's the mechanism for RSRLOAD  and do I have to initialize the Read Shift Register to use the ROI mode? Also I read in the datasheet that WSROUT will give RSR output when DWRITE is low. Sometimes I see some random bits from this output and sometimes I see all zero's. What is the reasonable output I should see from WSROUT, say, when I'm running in the transparent mode with DWRITE low?

    Thank you very much!

Hi Stefan,

    I tried again and confirmed the problem... In the full readout mode I could successfully read out all the data, but in the ROI mode if I naively apply a pulse at RSRLOAD the results are not right. Is there anything I should be careful about in the ROI readout mode?

    Thanks!

Hi Stefan,

    in the DRS4 datasheet I read that the optimal frequency for SRCLK is 33MHz. However in the evaluation board firmware SRCLK is toggled at rising edges of the internal 33MHz clock, i.e. the frequency of SRCLK itself is 16.5MHz instead. Is that frequency better than 33MHz?

    Thanks!

Hi Stefan,

    I read in the DRS datasheet that the input bandwidth if 950MHz. However, it also says the output bandwidth in the transparent mode is 50MHz. Since in the transparent mode the input is routed to the output, does it mean the input bandwidth also gets reduced in the transparent mode? I don't know how the transparent mode works inside the chip of course, but this value would be important since if the hardware discriminators are connected to the output of DRS, we have to always work in the transparent mode.

    Thanks!

 Thanks! The suggested algorithm looks promising. However, if the spikes take place only for those specific cells, is it possible to absorb them into the offset calibration?

Hi Stefan,

    in the datasheet it says at 6GSPS the typical loop filter parameters are 220Ω, 2.2nF and 27nF. If I want to run the Domino wave nominally at 1GHz, i.e. with a reference clock frequency around 0.5MHz, is there any recommended loop filter configuration? Is the setup of the evaluation board, that is, 220Ω, 3.3nF and 33nF an optimal choice?

    Thank you very much.

Hi Stefan,

    according to the DRS4 datasheet, if we want an input range centered around U0, the ROFS should be 1.55V-U0. However when I read the codes of the evaluation board application, ROFS seems to be 1.6V-1.25*U0 where the coefficient 1.25 is said to come from sampling cell charge injection correction. Is it the right equation to use? What exactly does that charge injection correction mean?

    Thanks a lot.

Hi Stefan,

    when I sample a constant input with the DRS 4 chip, there was a baseline variation showing up as a saw-tooth pattern which grows with the absolute value of the differential input. Do you think this is the kind of baseline variation mentioned in the evaluation board manual, i.e. coming from clock jitter in ADC sampling?

    Thanks a lot!

Hi Stefan,

    on our board some DRS chips draw a lot of current through DVDD after power-up and heat up significantly--it is true that our board doesn't have weak pull-down resistors at DENABLE and DWRITE output pins of FPGA, so this problem might have been caused by that, but a reinitialization of the Domino circuit doesn't help either. We tried different capacitors at DVDD and it seemed the larger the capacitance, the better the result--with a capacitor larger than 10nF some of the DRS chips could work happily in the normal way while if the capacitor is only 4.7nF all of them got very hot. Would you please provide some suggestions why there should be such a problem?

    Thanks a lot!