altos: Add separate 'ao_launch_tick'. Use in pyro and lockout.

Prior to this, there was only ao_boost_tick, which got reset at each
motor burn start. That meant there wasn't any way to measure total
flight time for pyro channels and 'apogee lockout' was based on time
since most recent motor start instead of total flight time.

Now pyro channels and apogee lockout both use total flight time, while
motor burn length still uses time since most recent motor burn start
(as it should).

Docs and UI updated to use 'launch' instead of 'boost' to try and make
the change clear.

Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 7 insertions, 3 deletions

diff --git a/doc/pyro-channels.inc b/doc/pyro-channels.inc
index 68bbf910..ab5baef0 100644
--- a/doc/pyro-channels.inc
+++ b/doc/pyro-channels.inc
@@ -42,9 +42,13 @@ launch pad and initialize the system.
   of less than that value.
   ====
 
-Flight Time:: Time since boost was detected. Select a value and choose
-whether to activate the pyro channel before or after that amount of
-time.
+Flight Time:: Time since launch. Select a value and choose whether to
+activate the pyro channel before or after that amount of time.
+
+[WARNING]
+Firmware versions older than 1.8.6 have a bug which resets the time
+since launch to zero each time a motor starts burning. Update firmware
+to get the correct behavior.
 
 Ascending:: A deprecated configuration value which was the same as
 setting Ascent rate > 0. Existing configurations using this will be