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Alphabets uses two communication layers. The application layer talks in text; the module layer talks in physical drum positions.
flowchart LR
A[Application] -->|Message protocol: text and layout| C[Controller]
C -->|Module protocol: positions 0-63| M[Module chain]
M -->|Ready and current position| C
C -->|Accepted, ready, or error| A
Applications send newline-delimited UTF-8 JSON. A display.show request can
contain text plus wrapping and alignment preferences. The controller knows the
real number of rows and columns and refuses text that cannot fit or cannot be
shown by the installed character set.
The controller first replies that a valid update was accepted. When every module reaches its target, it reports that the display is ready.
Read the complete message protocol and its JSON Schema.
The controller opens a frame with LATCH, shifts one byte per module using a
shared clock, and closes the frame. Commands 0x01 through 0x40 mean drum
positions 0 through 63. 0x41 starts automatic homing on V2 Final modules.
Each status byte says whether a module is present, whether it is ready, and which position it currently shows. Commands travel in reverse physical order because every module forwards the byte it receives to the next module.
Read the complete ATtiny1624 module protocol. The older ATtiny44 protocol is kept for V2 Prototype hardware.
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