1 files changed, 90 insertions, 0 deletions
diff --git a/stm32/src/tot.c b/stm32/src/tot.c
new file mode 100644
index 0000000..1fce495
--- /dev/null
+++ b/stm32/src/tot.c
@@ -0,0 +1,90 @@
+/*!
+ * Time-out timer.
+ *
+ * This is a simple time-out timer for ensuring a maximum transmission
+ * time is observed.  The time-out timer is configured with a total time
+ * in "ticks", which get counted down in an interrupt.
+ *
+ * When the "warning" level is reached, a flag is repeatedly set permit
+ * triggering of LEDs/sounds to warn the user that time is nearly up.
+ *
+ * Upon timeout, a separate flag is set to indicate timeout has taken
+ * place.
+ *
+ * Author Stuart Longland <[email protected]>
+ * Copyright (C) 2015 FreeDV project.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License version 2.1,
+ * as published by the Free Software Foundation.  This program 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 Lesser General Public
+ * License along with this program; if not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+
+#include "tot.h"
+
+/*!
+ * Reset the time-out timer.  This zeroes the counter and event flags.
+ */
+void tot_reset(struct tot_t * const tot)
+{
+	tot->event		= 0;
+	tot->remaining		= 0;
+	tot->warn_remain	= 0;
+	tot->ticks		= 0;
+}
+
+/*!
+ * Start the time-out timer ticking.
+ */
+void tot_start(struct tot_t * const tot, uint32_t tot_ticks,
+		uint16_t warn_ticks)
+{
+	tot->event		= TOT_EVT_START;
+	tot->warn_remain	= tot_ticks - warn_ticks;
+	tot->remaining		= tot_ticks;
+	tot->ticks		= tot->tick_period;
+}
+
+/*!
+ * Update the time-out timer state.
+ */
+void tot_update(struct tot_t * const tot)
+{
+	if (!tot->event)
+		/* We are not active */
+		return;
+
+	if (tot->event & TOT_EVT_DONE)
+		/* We are done, do not process */
+		return;
+
+	if (tot->ticks)
+		/* Wait for a tick to pass */
+		return;
+
+	/* One "tick" has passed */
+	if (!tot->remaining) {
+		/* Time-out reached, reset all flags except timeout */
+		tot->event	|= TOT_EVT_TIMEOUT | TOT_EVT_DONE;
+		return;
+	} else {
+		tot->remaining--;
+	}
+
+	if (!tot->warn_remain) {
+		/* Warning period has passed */
+		tot->event	|= TOT_EVT_WARN | TOT_EVT_WARN_NEXT;
+		tot->warn_remain = tot->remain_warn_ticks;
+	} else {
+		tot->warn_remain--;
+	}
+
+	tot->ticks = tot->tick_period;
+}