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Native Text Scroll Protocol (ACT1025)

Date: 2026-03-15

Current production rule

After end-to-end hardware validation, the stable routing rule is:

  • Default and supported route: native-type4-route for all text lengths (>= 1 char)

Reason: native-type4-route is the only route that validated consistently across short, medium, and long strings in our latest tests.

Handshake / open sequence

Before text payload, send:

  1. 08 00 01 80 HH MM SS 00
  2. 04 00 05 80
  3. 05 00 12 80 07
  4. 07 00 08 80 01 00 CH

Then send text payload frame(s).

native-type4-route frame (type-4 channel payload)

Observed accepted framing (from app captures and validated sender):

  • Bytes 0..1: framed packet length (LE)
  • Bytes 2..3: data type 00 01
  • Byte 4: type 00
  • Bytes 5..8: totalData length (LE)
  • Bytes 9..12: CRC32(totalData) (LE)
  • Bytes 13..14: route marker/trailer 00 65
  • Bytes 15..: totalData

Long payloads are segmented into multiple BLE writes (chunked value writes).

totalData text record layout

  • Byte 0: text length (1-byte)
  • Byte 1: 00
  • Bytes 2..3: 01 01
  • Byte 4: effect code
  • Bytes 5..6: 50 00
  • Bytes 7..20: color prelude
    • fg(3) + bg(3) + 00 00 + fg(3) + bg(3)
  • Bytes 21..: glyph records
    • first glyph + separator
    • then repeated fg + bg + glyph + separator

Effect codes:

  • 0=fixed
  • 1=scroll-left
  • 2=scroll-right
  • 5=blinking
  • 6=breathing
  • 7=snowflake
  • 8=laser

Validation status

Visually validated on panel:

  • short text (1, 2, 3, 5, 8, 10 chars)
  • medium text (11 chars)
  • long text (>11, including repeated "Hello World" long string)
  • effects and color

Notes

  • Success criterion is always visual panel rendering (not BLE write/ack alone).
  • Glyph rendering uses the repo native font mapping (scripts/ipixel_font_map.py).