Tools: add script which tells you how Copter.ap changes over time

This is a global state object which we really want to get rid of - but
while we have it it does contain some useful state.

pbarker@bluebottle:~/rc/ardupilot(pr/du32-change)$ ./Tools/scripts/du32_change.py ~/rc/log32.bin
1648874490: Creating connection
Original armed_with_airmode_switch: 0
Original auto_armed: 0
Original compass_mot: 0
Original gps_glitching: 0
Original in_arming_delay: 1
Original initialised: 1
Original initialised_params: 1
Original land_complete: 1
Original land_complete_maybe: 1
Original land_repo_active: 0
Original logging_started: 1
Original motor_interlock_switch: 0
Original motor_test: 0
Original new_radio_frame: 1
Original pre_arm_check: 1
Original pre_arm_rc_check: 1
Original prec_land_active: 0
Original rc_receiver_present: 1
Original system_time_set_unused: 0
Original throttle_zero: 1
Original unused1: 0
Original unused2: 0
Original unused3: 0
Original unused_was_simple_mode bit1: 0
Original unused_was_simple_mode bit2: 0
Original usb_connected_unused: 0
Original using_interlock: 0
2022-04-01 08:19:27.03:  -in_arming_delay
2022-04-01 08:19:31.04:  +auto_armed -throttle_zero
2022-04-01 08:19:38.04:  -land_complete -land_complete_maybe
2022-04-01 08:20:34.29:  +throttle_zero
2022-04-01 08:20:35.29:  -auto_armed +land_complete +land_complete_maybe
pbarker@bluebottle:~/rc/ardupilot(pr/du32-change)$

Tools/scripts/du32_change.py

@@ -0,0 +1,118 @@
+#!/usr/bin/env python
+
+"""
+Parses a log file and shows how Copter's du32 changes over time
+
+AP_FLAKE8_CLEAN
+
+"""
+
+from __future__ import print_function
+
+import optparse
+import sys
+import time
+
+from pymavlink import mavutil
+
+
+class DU32Change(object):
+    def __init__(self, master):
+        self.master = master
+
+    def progress(self, text):
+        '''emit text with possible timestamps etc'''
+        print("%u: %s" % (time.time(), text))
+
+    def run(self):
+
+        self.progress("Creating connection")
+        self.conn = mavutil.mavlink_connection(master)
+
+        # this eas was generated from Copter.h's structure for ap_t:
+        bit_descriptions_list = [
+            "unused1",
+            "unused_was_simple_mode bit1",
+            "unused_was_simple_mode bit2",
+            "pre_arm_rc_check",
+            "pre_arm_check",
+            "auto_armed",
+            "logging_started",
+            "land_complete",
+            "new_radio_frame",
+            "usb_connected_unused",
+            "rc_receiver_present",
+            "compass_mot",
+            "motor_test",
+            "initialised",
+            "land_complete_maybe",
+            "throttle_zero",
+            "system_time_set_unused",
+            "gps_glitching",
+            "using_interlock",
+            "land_repo_active",
+            "motor_interlock_switch",
+            "in_arming_delay",
+            "initialised_params",
+            "unused3",
+            "unused2",
+            "armed_with_airmode_switch",
+            "prec_land_active",
+        ]
+        bit_descriptions = {}
+        count = 0
+        for bit in bit_descriptions_list:
+            bit_descriptions[bit] = count
+            count += 1
+
+        old_m = None
+
+        desired_type = "DU32"
+        while True:
+            m = self.conn.recv_match(type=desired_type)
+            if m is None:
+                break
+            if m.Id != 7:
+                # 7 is LOG_DATA_ID from AP_Logger.h
+                continue
+            if old_m is not None and m.Value == old_m.Value:
+                continue
+            line = ""
+            if old_m is None:
+                for bit in sorted(bit_descriptions.keys()):
+                    bit_set = m.Value & (1 << bit_descriptions[bit])
+                    if bit_set:
+                        print("Original %s: 1" % bit)
+                    else:
+                        print("Original %s: 0" % bit)
+            else:
+                for bit in bit_descriptions.keys():
+                    old_bit_set = old_m.Value & (1 << bit_descriptions[bit])
+                    new_bit_set = m.Value & (1 << bit_descriptions[bit])
+                    if new_bit_set and not old_bit_set:
+                        line += " +%s" % bit
+                    elif not new_bit_set and old_bit_set:
+                        line += " -%s" % bit
+
+                timestamp = getattr(m, '_timestamp', 0.0)
+                formatted_timestamp = "%s.%02u" % (
+                    time.strftime("%Y-%m-%d %H:%M:%S", time.localtime(timestamp)),
+                    int(timestamp * 100.0) % 100)
+
+                print("%s: %s" % (formatted_timestamp, line))
+            old_m = m
+
+
+if __name__ == '__main__':
+    parser = optparse.OptionParser("du32_change.py [options]")
+
+    (opts, args) = parser.parse_args()
+
+    if len(args) < 1:
+        parser.print_help()
+        sys.exit(1)
+
+    master = args[0]
+
+    tester = DU32Change(master)
+    tester.run()