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High-rate encoder (hrencoder)

Debugging

devGui

The high-rate encoder firmware is located at high-rate-encoder-dev, the devGui is included in the repository. To clone it:

Registers

• TriggerEventBuffer.TriggerDelay is an additional trigger seen by the encoder
  • Units 185.7 MHz clocks
  • Provides a knob for timing the trigger to get the correct encoder reading per event.
  • Default value (if not running from DAQ) is 42 - too small to affect dead time issues.
• Set TriggerEventBuffer.TriggerSource  to XPM (0) - Evr is the other option (LCLSI)
• Set EventBuilder.Partition to group
• Set EventBuilder.Bypass  to 0x4 to bypass full timing stream which has no buffer and is not needed for the high-rate encoder.

Data Format

This information also available at the firmware repository.

Data is on SFP[0], VC[1] Subframe 2, counting from 0.

The data message is:

BIT[31:00] = Encoder position
BIT[39:32] = Encoder Error Counter
BIT[47:40] = Missed Trigger Counter
BIT[48]    = "E" latch
BIT[49]    = "P" latch
BIT[50]    = "Q" latch
BIT[63:51] = Reserved (zeros)

Debugging

devGui

The high-rate encoder firmware is located at high-rate-encoder-dev, the devGui is included in the repository. To clone it:

GIT_LFS_SKIP_SMUDGE=1 git clone git@github.com:slaclab/high-rate-encoder-dev 

GIT_LFS_SKIP_SMUDGE=1 git clone git@github.com:slaclab/high-rate-encoder-dev --recursive

The devGui  can then be run from high-rate-encoder-dev/software as:

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• The script must be run from the software directory as it looks for a configuration YAML that is located at config/defaults.yml .
• It requires the lane  not the lane mask . As of 2024/03/29, the high-rate encoder is drp-srcf-cmp004 lane 7.
• --standAloneMode  is for running off of internal timing.

devGui + DAQ Simultaneously

It is possible to run the full devGui  (not the "Spy-mode" described above) alongside the DAQ with a bit of hack. This works fairly well with the hrencoder  because the hrencoder_config.py  is fairly simple. It may be of use if you can transition to configure but not beyond. To run the DAQ alongside the devGui , you can:

1. First open the DAQ alongside the spy-GUI described above.
2. Pass through the Configure  transition.
3. Switch to the "spy-mode devGui" and save a YAML file containing the current configuration.
4. Close the DAQ and edit hrencoder_config.py (or other equivalent detector) - remove the Root  object and all register accesses from the file.
5. Reopen the DAQ and rerun the devGui . Swich to the System  tab and browse to and load the YAML file you saved previously.
6. Transition to Configure and run etc..
   1. You have to load the YAML before transitioning to configure.

Restarting IOCs

(courtesy of Tyler Johnson)

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