FADC Data Format June 9, 2015

Location and Time

Room: CC L207 ??

Time: 2pm.

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Agenda

• Previous meeting (Apr 21, 2015)
• Status of FADC125 Firmware
• Configuration parameters
• Emulation

Useful Links

• Timing algorithm - updated to include latest revisions
• fADC125 Data Format Specification Document Latest version (5.01) in svn, 17 Feb 2015 Even Later version (5.03) in svn, 11 March 2015
• Data format for 250 modes on fADC125 from Cody, Aug 15 2014
• FA250 modes 2 from Ed and Hai, Feb 18 2014
• FIRMWARE for FADC250 Ver2 ADC FPGA, Sept 2014?
• FDC_pulse_data_format
• CDC readout needs Garfield calcs
• CDC_run_985 CDC_run_970

Minutes

Present: Naomi (CMU), Cody, Elton, David, Beni (JLab)

1. Cody is still finding a few signals which do not make timing (ie the signal needs more than one clock cycle to get from one state to the next, the delays can be due to excess logic or routing or both) in the full version of the new firmware, where all the possible output quantities are calculated and then selected for output according to the data format mode in use. More than 80% of the FA125 resources are in use; this is after redoing the daisy-chaining and back-end.
2. However, the code for just one readout format - the CDC combination mode - does make timing. This needs to have the configuration parameters finalized and Cody will ask Bryan for the readout library so that he can test it (the library supplies the register space for the configuration parameters and the data decoder). Cody asked about doing full crate tests to check the trigger rates, Beni said yes, do this as soon as he can.
3. Cody will keep working on the full version. If it does not seem likely that this will be successful, the backup plan is to make separate firmware versions for the CDC and FDC.
4. The timing algorithm has been fully pipelined, with every loop removed. XTHR_SAMPLE and NSAMPLES can be configurable. Naomi: we are ok with NSAMPLES constant.
5. Naomi: We can remove the tests for overflow and upsampling errors as these can be identified offline.
6. Naomi has been looking at prototype data to see if XTHR_SAMPLE should be configurable (probably, yes) and if using a mean of a number of samples for the timing pedestal gives better results than a single sample (so far, no, but needs further work).
7. Naomi mentioned reducing the upsampling factor. This would not help with synthesis (making timing), but would make the process finish sooner.
8. Elton mentioned that the FA250 team are planning to revise their firmware and might adopt some similar tactics to the FA125's.
9. Lubomir asked about the FA125 self-triggering. Cody will look to see how long this would be likely to take to implement.