[shuckc]

Reads the machine's command set and NC Code preferences at connect, shows the command set in the header, and adds an n dialog to change them.

What the machine config is

The 6-byte GET 0x3106 / SET 0x3107 struct carries the command set and, from VPanel's "NC Code setting" page (FUN_00404ff0 / FUN_00405040), three NC Code preferences. Each byte is the MFC radio index of a VPanel control:

Byte	Meaning	Values
1	command set	RML-1 (0), NC Code (1), Auto (2)
2	decimal-point method	Conventional (0), Calculator [All] (1), [F] (2), [IJKRXYZA] (3)
3	tool-diameter offset type	Type A (0), Type B (1)
4	optional block	Enabled (0), Disabled (1)

Bytes 0 and 5 are never edited by VPanel and are round-tripped. VPanel writes only when something changed, and enables the NC Code page only for the NC Code and automatic command sets.

Changes

• machine: MachineConfig decodes the struct. It is read at connect and logged in full at startup (Machine config: command set …, tool-dia offset paths …, decimal point …, optional block … [00 01 00 00 00 05]). write_config() changes any of the fields with one validated read-modify-write, waits for the ack and reads back to verify. set_command_set() now delegates to it, and the unused MDX40A.CMDSET_* class attributes are gone (the constants are module-level).
• tui: the header shows RML-1 mode, NC mode or Auto-mode. n opens a Command Mode dialog (command set plus Tool-dia offset paths Type A/B, decimal point, optional block): ↑↓ navigate, ↵ apply, Space select, Esc close. The NC Code preferences are locked unless the command set is NC Code or automatic, as in VPanel, and n is refused while a job is loaded. Changes are applied with a single write.
• The Z-probe dialog now uses the cached command set instead of reading it each time it opens, and also warns that VPanel hides User in NC Code mode.
• docs: a "Machine config struct" section in usb-protocol.md, notes in sending-nc-code.md, and the n key in the README.

Test plan

• pytest -q: 206 passed, 1 skipped
• tests/test_machine_config.py (exact bytes written, only the edited bytes change, no write when unchanged, validation, failed read-back, the startup banner) and tests/test_cmd_mode.py (dialog flow, locked preferences, one write per apply, no write on Esc)
• ruff check on the test files touched
• Reading and writing these values was tested on a real MDX-40A (by the author)

🤖 Generated with Claude Code