grblHAL Setup

grblHAL is a high-performance CNC controller firmware that ncSender fully supports.

Connection

• USB — Standard serial connection at 115200 baud
• Ethernet — TCP or WebSocket connection (if your board supports networking)

grblHAL boards typically use DTR for USB CDC communication. ncSender handles this automatically.

Firmware Settings

Access firmware settings through the console:

• $$ — List all settings
• $<number>=<value> — Set a specific value (e.g., $110=5000)
• $help — Show available commands

Key Settings

Setting	Description	Example
$22	Homing enable	1 (enabled)
$32	Laser mode	1 (laser), 0 (normal)
$110-$112	Max feed rate (X/Y/Z)	5000 mm/min
$120-$122	Acceleration (X/Y/Z)	500 mm/sec^2
$130-$132	Max travel (X/Y/Z)	1200 mm

Status Reporting

ncSender polls grblHAL for status at the configured polling interval (default 100ms). The status report includes:

• Machine and work positions
• Machine state (Idle, Run, Hold, Alarm, etc.)
• Feed rate and spindle speed
• Pin states (probe, limits, door)
• Overrides (feed, rapid, spindle)
• Work Coordinate Offset (WCO)

Alarms

grblHAL alarm codes are automatically fetched and displayed with descriptions. Use $X to clear alarms, or the Unlock button in the toolbar.

Probing

grblHAL supports:

• G38.2 — Probe toward target, error if no contact
• G38.3 — Probe toward target, no error
• G38.4 — Probe away from target, error if no contact break
• G38.5 — Probe away from target, no error

Realtime Commands

ncSender uses grblHAL's realtime commands for instant response:

Byte	Command
!	Feed hold
~	Cycle start / Resume
?	Status query
0x18	Soft reset
0x85	Jog cancel
0x87	Full status report
0xA0	Toggle flood coolant
0xA1	Toggle mist coolant

These bypass the planner buffer and execute immediately.