AP_DDS: RC channels message

[tizianofiorenzani]

Issue

#28888

What Changed

New /ap/rc DDS topic reporting the current status and values of the RC receiver.

• is_connected: true if the radio is connected.
• receiver_rssi: 0 to 100 if the RSSI is available.
• channels: vector of maximum 32 pwm channels (usually 1000 to 2000).
• active_overrides: vector reporting whether the corresponding channel is overridden by GCS or DDS.

Topic is published at 10Hz when RC is connected, 1Hz when disconnected.

Test

• I used a MatekH743 autopilot and a FrSky X8R receiver.
• The RSSI receiver pin is connected to the RSSI pin ADC of the Matek autopilot.
• RSSI_ANA_PIN = 8, RSSI_PIN_HIGH = 3, RSSI_TYPE = 1.

Topic Output

With the autopilot connected through micro-ros, echo the topic with ros2 topic echo /ap/rc.

Boot with RC disconnected

header:
  stamp:
    sec: 25
    nanosec: 732212000
  frame_id: ''
is_connected: false
receiver_rssi: 0
channels: []
active_overrides: []

RC Connected

---
header:
  stamp:
    sec: 477
    nanosec: 419094000
  frame_id: ''
is_connected: true
receiver_rssi: 100
channels:
- 1495
- 1495
- 1466
- 1509
- 982
- 1495
- 1495
- 982
- 1495
- 1495
- 1495
- 1495
- 1495
- 1495
- 1495
- 1495
active_overrides:
- false
- false
- false
- false
- false
- false
- false
- false
- false
- false
- false
- false
- false
- false
- false
- false

RC Disconnected

header:
  stamp:
    sec: 525
    nanosec: 182030000
  frame_id: ''
is_connected: false
receiver_rssi: 0
channels:
- 1495
- 1495
- 1466
- 1509
- 982
- 1495
- 1495
- 982
- 1495
- 1495
- 1495
- 1495
- 1495
- 1495
- 1495
- 1495
active_overrides:
- false
- false
- false
- false
- false
- false
- false
- false
- false
- false
- false
- false
- false
- false
- false
- false

RC Connected and Overridden

Use Mavproxy to override RC channel 3.

header:
  stamp:
    sec: 593
    nanosec: 228105000
  frame_id: ''
is_connected: true
receiver_rssi: 95
channels:
- 1495
- 1495
- 1800
- 1509
- 982
- 1495
- 1495
- 982
- 1495
- 1495
- 1495
- 1495
- 1495
- 1495
- 1495
- 1495
active_overrides:
- false
- false
- true
- false
- false
- false
- false
- false
- false
- false
- false
- false
- false
- false
- false
- false

[Ryanf55]

Why only 8 channels?

[tizianofiorenzani]

@Ryanf55 updated and tested to a max of 32 channels.