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AP_FETtecOneWire: Fix spelling in comments (NFC)

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Dr.-Ing. Amilcar do Carmo Lucas 2022-01-03 19:30:13 +01:00 committed by Peter Barker
parent bfded82da5
commit 95effd59ea
2 changed files with 10 additions and 10 deletions
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2
libraries/AP_FETtecOneWire/AP_FETtecOneWire.cpp
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@ -141,7 +141,7 @@ void AP_FETtecOneWire::init()
// initialise ESC ids. This enforces that the FETtec ESC ids
// inside FETtec ESCs need to be contiguous and start at ID 1
// which required by fast-throttle commands.
// which is required by fast-throttle commands.
uint8_t esc_offset = 0; // offset into our device-driver dynamically-allocated array of ESCs
uint8_t esc_id = 1; // ESC ids inside FETtec protocol are one-indexed
uint8_t servo_chan_offset = 0; // offset into _motor_mask_parameter array

18
libraries/AP_FETtecOneWire/README.md
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@ -4,7 +4,7 @@ FETtec OneWire is an [ESC](https://en.wikipedia.org/wiki/Electronic_speed_contro
It is a (bidirectional) [digital full-duplex asynchronous serial communication protocol](https://en.wikipedia.org/wiki/Asynchronous_serial_communication) running at 500Kbit/s Baudrate. It requires three wire (RX, TX and GND) connection (albeit the name OneWire) regardless of the number of ESCs connected.
Unlike bidirectional-Dshot, the FETtec OneWire protocol does not need one DMA channel per ESC for bidirectional communication.
For purchase, connection and configuration information please see the [Ardupilot FETtec OneWire wiki page](https://ardupilot.org/copter/docs/common-fettec-onewire.html).
For purchase, connection and configuration information please see the [ArduPilot FETtec OneWire wiki page](https://ardupilot.org/copter/docs/common-fettec-onewire.html).
## Features of this device driver
@ -39,9 +39,9 @@ For purchase, connection and configuration information please see the [Ardupilot
- fly a copter over a simulated serial link connection
## Ardupilot to ESC protocol
## ArduPilot to ESC protocol
The FETtec OneWire protocol supports up to 24 ESCs. As most copters only use at most 12 motors, Ardupilot's implementation supports only 12 (`ESC_TELEM_MAX_ESCS`)to save memory.
The FETtec OneWire protocol supports up to 24 ESCs. As most copters only use at most 12 motors, ArduPilot's implementation supports only 12 (`ESC_TELEM_MAX_ESCS`)to save memory.
There are two types of messages sent to the ESCs configuration and fast-throttle messages:
@ -95,7 +95,7 @@ The signal is used to transfer the eleven bit throttle signals with as few bytes
All motors wait for the complete message with all throttle signals before changing their output.
If telemetry is requested the ESCs will answer them in the ESC-ID order.
See *ESC to Ardupilot Protocol* section below and comments in `AP_FETtecOneWire.cpp` for details.
See *ESC to ArduPilot Protocol* section below and comments in `AP_FETtecOneWire.cpp` for details.
### Timing
@ -103,13 +103,13 @@ See *ESC to Ardupilot Protocol* section below and comments in `AP_FETtecOneWire.
Four ESCs need 90us for the fast-throttle request and telemetry reception. With four ESCs 11kHz update would be possible.
Each additional ESC adds 11 extra fast-throttle command bits, so the update rate is lowered by each additional ESC.
If you use 8 ESCs, it needs 160us including telemetry response, so 5.8kHz update rate would be possible.
The FETtec Ardupilot device driver limits the message transmit period to `_min_fast_throttle_period_us` according to the number of ESCs used.
The FETtec ArduPilot device driver limits the message transmit period to `_min_fast_throttle_period_us` according to the number of ESCs used.
The update() function has an extra invocation period limit so that even at very high loop rates the the ESCs will still operate correctly albeit doing some decimation.
The current update rate for Copter is 400Hz (~2500us) and for other vehicles is 50Hz (~20000us) so we are bellow device driver limit.
**Note:** The FETtec ESCs firmware requires at least a 4Hz fast-throttle update rate (max. 250ms between messages) otherwise the FETtec ESC disarm (stop) the motors.
## ESC to Ardupilot protocol
## ESC to ArduPilot protocol
OneWire ESC telemetry information is sent back to the autopilot:
@ -120,7 +120,7 @@ OneWire ESC telemetry information is sent back to the autopilot:
- Temperature (°C/10)
- CRC errors (ArduPilot->ESC) counter
This information is used by Ardupilot to:
This information is used by ArduPilot to:
- log the status of each ESC to the SDCard or internal Flash, for post flight analysis
- send the status of each ESC to the ground station or companion computer for real-time monitoring
@ -137,8 +137,8 @@ The data is forwarded to the `AP_ESC_Telem` class that distributes it to other p
There are two public top level functions `update()` and `pre_arm_check()`.
And these two call all other private internal functions.
A single (per ESC) state variable (`_escs[i]._state`) is used in both the RX and TX state machnines.
Here is the callgraph:
A single (per ESC) state variable (`_escs[i]._state`) is used in both the RX and TX state machines.
Here is the call graph:
```
update()