id: apollo_pcm_frame_sync
label: Apollo PCM Frame Sync
category: '[Apollo USB]'
flags: [python]

parameters:
- id: bit_rate
  label: Bit Rate (bps)
  dtype: int
  default: '51200'
  options: ['51200', '1600']
  option_labels: ['High (51.2 kbps)', 'Low (1.6 kbps)']
- id: max_bit_errors
  label: Max Sync Bit Errors
  dtype: int
  default: '3'

inputs:
- label: in
  domain: stream
  dtype: byte

outputs:
- label: frames
  domain: message

templates:
  imports: from apollo import pcm_frame_sync
  make: >-
    apollo.pcm_frame_sync.pcm_frame_sync(
      bit_rate=${bit_rate},
      max_bit_errors=${max_bit_errors})

documentation: |-
  Apollo PCM Frame Synchronizer

  Acquires the 32-bit frame sync pattern from an NRZ bit stream and
  outputs complete PCM frames as PDU messages.

  The sync word format is:
    [5-bit A][15-bit core][6-bit B][6-bit frame ID]

  The 15-bit core is complemented on odd-numbered frames. The correlator
  checks against both patterns simultaneously using Hamming distance.

  State machine: SEARCH -> VERIFY -> LOCKED (back to SEARCH on N misses).

  Parameters:
    bit_rate: 51200 (128 words/frame, 50 fps) or 1600 (200 words/frame, 1 fps)
    max_bit_errors: Hamming distance threshold for sync detection (default 3)

  Output PDU metadata:
    frame_id:        Frame number within subframe (1-50)
    odd_frame:       True if odd frame (complemented core)
    sync_confidence: Number of correct sync bits (out of 32)
    timestamp:       System time at frame detection

file_format: 1