[Halld-offline] New fADC250 data format + sim-recon

[Alexander Somov]

Hi Sean,

The pedestal sum (14 bits) is reported by the
firmware. Pedestals are summed in a window
with programmable size  (Min = 4 samples
and Max = 15 samples). I guess that David is
not normalizing pedestals in Df250PulsePedestal.
The window size will be stored in rcdb and
data stream (the default value is 4 samples).

Quality bits reported by fadc:

-----------------------------
a) pedestal quality (bit 14)
It is set to 1 if any of amplitudes in the
pedestal window are larger than a threshold
(programmable parameter, defaulted to 512
fadc counts) The threshold will be stored
in the rcdb and data stream.

b) pulse integral quality (bits 9, 10, 11)
bit 9  : one (or more samples) is underflow
bit 10 : one (or more samples) is overflow
bit 11 : NSA extends beyond the readout window


c) time quality bit (bits 0, 1, 2)
bit 1: peak cannot be found
bit 2: peak is beyond NSA (or window end)

You can find more details about the format
and processing in:

https://halldweb.jlab.org/level-1/manuals/FADC250/FADC250_Processing_FPGA_Firmware_ver_0x0C00_Description_Instructions.pdf

Cheers,
       Alex




On Thu, 15 Sep 2016, Sean Dobbs wrote:

> Hi David,
>
> Thanks a lot for the update.  Did you push the branch to the github
> server?  I see a branch with that name there, but it's 7 days old.
>
> Also, is there a copy of the data format specification that exists?  I'm
> particularly curious:
> 1) If the pedestal value is reported in the same way as the previous
> firmware (i.e., it corresponds to the pedestal for a single sample)
> 2) How firmware errors are reported, or what QF values we need to worry
> about to start off with.
>
> Hopefully we'll get some data soon to test this with =)
>
> Cheers,
> Sean
>
>
> On Thu, Sep 15, 2016 at 1:04 PM David Lawrence <davidl at jlab.org> wrote:
>
>> Dear fADC250 fans,
>>
>>   I have just pushed some changes to a branch (davidl_Df250PulseData) to
>> support
>> the new f250 firmware at the digihit level for all detectors. As you may
>> know, the new
>> firmware includes a new data type that combines information previously
>> spread over
>> the following classes:
>>
>> Df250PulseIntegral
>> Df250PulseTime
>> Df250PulsePedestal
>>
>> The new class that reflects this new data type is:
>>
>> Df250PulseData
>>
>>
>> The digihits actually did not require much change since they already
>> contained
>> members to hold values from the 3 older classes. The changes are:
>>
>> 1. The “pulse_peak" value is now a member of all digihit classes derived
>> from fADC250 data
>> (BCAL already contained this, but now all others do as well)
>>
>> 2. A new member “datasource” has been added that will be set to “1” for
>> the old firmware
>> and “2” for the new firmware. This may also be set to “0” if the emulate
>> flag is set
>> indicating that the values were derived from Window Raw Data
>>
>> 3. The QF value is now a combination of 7 quality factor bits when the
>> data comes
>> from the new firmware. i.e. Interpretation of the QF value should depend
>> on the value
>> of “datasource”.
>>
>>
>> Finally, one additional piece of information available in the new firmware
>> is the
>> "nsamples_over_threshold”. Currently, this is available in the
>> Df250PulseData
>> which may be obtained from the digihit via the Associated Objects
>> mechanism.
>> I did not add an additional member to all digihits to hold another copy of
>> this
>> value. If there is strong desire to make an additional copy of this value
>> at the digihits
>> level then we can do that. We could also consider adding it as some higher
>> bits
>> to the QF value.
>>
>> I will likely put a pull request in for this soon. If I get a file with
>> the new format soon
>> I will test it on that first. Otherwise, I’ll just put in the pull request
>> and we can debug
>> it on the master.
>>
>> Regards,
>> -David
>>
>>
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