docs: bidirectional dshot

docs/en/peripherals/dshot.md

@@ -36,7 +36,7 @@ Remove propellers before changing ESC configuration parameters!
 
 Enable DShot for your required outputs in the [Actuator Configuration](../config/actuators.md).
 
-DShot comes with different speed options: _DShot150_, _DShot300_, _DShot600_ and _DShot1200_, where the number indicates the speed in kilo-bits/second.
+DShot comes with different speed options: _DShot150_, _DShot300_, and _DShot600_ where the number indicates the speed in kilo-bits/second.
 You should set the parameter to the highest speed supported by your ESC (according to its datasheet).
 
 Then connect the battery and arm the vehicle.
@@ -110,17 +110,18 @@ The most important ones are:
 
   :::
 
-## Telemetry
+## ESC Telemetry
 
-Some ESCs are capable of sending telemetry back to the flight controller, including:
+Some ESCs are capable of sending telemetry back to the flight controller through a UART RX port.
+These DShot ESCs will have an additional telemetry wire.
 
-- temperature
-- voltage
-- current
-- accumulated current consumption
-- RPM values
+The provided telemetry includes:
 
-These DShot ESCs will have an additional telemetry wire.
+- Temperature
+- Voltage
+- Current
+- Accumulated current consumption
+- RPM values
 
 To enable this feature (on ESCs that support it):
 
@@ -147,3 +148,40 @@ ERROR [dshot] No data received. If telemetry is setup correctly, try again.
 
 Check manufacturer documentation for confirmation/details.
 :::
+
+## Bidirectional DShot (Telemetry)
+
+<Badge type="tip" text="PX4 v1.16" />
+
+Bidirectional DShot is a protocol that can provide telemetry including: high rate ESC RPM data, voltage, current, and temperature with a single wire.
+
+The PX4 implementation currently enables only ESC RPM (eRPM) data collection from each ESC at high frequencies.
+This telemetry significantly improves the performance of [Dynamic Notch Filters](../config_mc/filter_tuning.md#dynamic-notch-filters) and enables more precise vehicle tuning.
+
+::: info
+The [ESC Telemetry](#esc-telemetry) described above is currently still necessary if you want voltage, current, or temperature information.
+It's setup and use is independent of bidirectional DShot.
+:::
+
+### Hardware Setup
+
+The ESC must be connected to FMU outputs only.
+These will be labeled `MAIN` on flight controllers that only have one PWM bus, and `AUX` on controllers that have both `MAIN` and `AUX` ports (i.e. FCs that have an IO board).
+
+:::warning **Limited hardware support**
+This feature is only supported on flight controllers with the following processors:
+
+- STM32H7: First four FMU outputs
+  - Must be connected to the first 4 FMU outputs, and these outputs must also be mapped to the same timer.
+  - [KakuteH7](../flight_controller/kakuteh7v2.md) is not supported because the outputs are not mapped to the same timer.
+- [i.MXRT](../flight_controller/nxp_mr_vmu_rt1176.md) (V6X-RT & Tropic): 8 FMU outputs.
+
+No other boards are supported.
+:::
+
+### Configuration {#bidirectional-dshot-configuration}
+
+To enable bidirectional DShot, set the [DSHOT_BIDIR_EN](../advanced_config/parameter_reference.md#DSHOT_BIDIR_EN) parameter.
+
+The system calculates actual motor RPM from the received eRPM data using the [MOT_POLE_COUNT](../advanced_config/parameter_reference.md#MOT_POLE_COUNT) parameter.
+This parameter must be set correctly for accurate RPM reporting.