Module packet 

The transmit-side packet builder — allocation-free.

Builds the full wire packet: command + checksum, encoded as UTF-8 bytes, written into a caller-provided buffer. The checksum is a bytewise sum mod 256, formatted as 2 uppercase hex chars — exactly the app’s SkydroidControl.getCrc.

Functions

build

Build the full wire packet from raw command bytes: command + checksum, written into out. Returns the total bytes written, or None if out is too small (cmd.len() + 2 needed).

build_command

Build a wire packet from any Command implementor, writing into out.

checksum_byte

Compute the checksum byte for a command: (sum of all bytes) mod 256.

checksum_hex

Compute the 2-character uppercase-hex checksum string as ASCII bytes.

verify

Given a full packet (cmd + 2-char checksum), verify the checksum matches.