Import grbl v1.1h
diff --git a/grbl/probe.c b/grbl/probe.c
new file mode 100644
index 0000000..60c9073
--- /dev/null
+++ b/grbl/probe.c
@@ -0,0 +1,66 @@
+/*
+ probe.c - code pertaining to probing methods
+ Part of Grbl
+
+ Copyright (c) 2014-2016 Sungeun K. Jeon for Gnea Research LLC
+
+ Grbl is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ Grbl is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with Grbl. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "grbl.h"
+
+
+// Inverts the probe pin state depending on user settings and probing cycle mode.
+uint8_t probe_invert_mask;
+
+
+// Probe pin initialization routine.
+void probe_init()
+{
+ PROBE_DDR &= ~(PROBE_MASK); // Configure as input pins
+ #ifdef DISABLE_PROBE_PIN_PULL_UP
+ PROBE_PORT &= ~(PROBE_MASK); // Normal low operation. Requires external pull-down.
+ #else
+ PROBE_PORT |= PROBE_MASK; // Enable internal pull-up resistors. Normal high operation.
+ #endif
+ probe_configure_invert_mask(false); // Initialize invert mask.
+}
+
+
+// Called by probe_init() and the mc_probe() routines. Sets up the probe pin invert mask to
+// appropriately set the pin logic according to setting for normal-high/normal-low operation
+// and the probing cycle modes for toward-workpiece/away-from-workpiece.
+void probe_configure_invert_mask(uint8_t is_probe_away)
+{
+ probe_invert_mask = 0; // Initialize as zero.
+ if (bit_isfalse(settings.flags,BITFLAG_INVERT_PROBE_PIN)) { probe_invert_mask ^= PROBE_MASK; }
+ if (is_probe_away) { probe_invert_mask ^= PROBE_MASK; }
+}
+
+
+// Returns the probe pin state. Triggered = true. Called by gcode parser and probe state monitor.
+uint8_t probe_get_state() { return((PROBE_PIN & PROBE_MASK) ^ probe_invert_mask); }
+
+
+// Monitors probe pin state and records the system position when detected. Called by the
+// stepper ISR per ISR tick.
+// NOTE: This function must be extremely efficient as to not bog down the stepper ISR.
+void probe_state_monitor()
+{
+ if (probe_get_state()) {
+ sys_probe_state = PROBE_OFF;
+ memcpy(sys_probe_position, sys_position, sizeof(sys_position));
+ bit_true(sys_rt_exec_state, EXEC_MOTION_CANCEL);
+ }
+}