[Sponsored by ARK] Bidirectional DShot (#23863)

* Bidirectional DShot

Co-authored-by: Julian Oes <[email protected]>

* f4/f1 support, not supported

* fix f1 build target

* sanity check timer_channel value, fix CCxNP ifdef, debug stuff

* removed debug code, added define for H7 HAVE_GTIM_CCXNP

* round robin sampling for less than 4 DMA

* unlimited esc_status logging

* dshot: fix formatting

* dshot: add define for number of DMA channels to use

This allows individual boards to override the number of DShot channels
and hence avoid round robin capture of the RPM feedback.

* ARK: enable 4 DMA channels for DShot on 6X

* dshot: publish when all channels are updated

This slows down the ESC_STATUS publication in the case of round robin
capture. E.g. for 800 Hz output with one DMA channel, the ESC_STATUS is
now published at 200 Hz.

* dshot: avoid duplicate publications for bidir and telem

Instead of publishing both bidirectional dshot updates as well as
telemetry updates, we now combine the data from both streams, and
publish whenever we get RPM updates, as the latter arrives with higher
rate, e.g. 200 Hz with round robin, or faster otherwise.

When combining the data, we take RPM from bidirectional dshot, and the
rest from telemetry.

When we have only one of the two, either telemetry or bidirectional
dshot, we just publish that one.

* boards: add ark fpv and pi6x BOARD_DMA_NUM_DSHOT_CHANNELS

* dshot: turn off debug build

---------

Co-authored-by: Julian Oes <[email protected]>
Co-authored-by: alexklimaj <[email protected]>

Author: 3 people

boards/ark/fmu-v6x/src/board_config.h

@@ -420,6 +420,9 @@
 /* This board provides a DMA pool and APIs */
 #define BOARD_DMA_ALLOC_POOL_SIZE 5120
 
+/* This board has 4 DMA channels available for bidirectional dshot */
+#define BOARD_DMA_NUM_DSHOT_CHANNELS 4
+
 /* This board provides the board_on_reset interface */
 
 #define BOARD_HAS_ON_RESET 1

boards/ark/fpv/src/board_config.h

@@ -307,6 +307,9 @@
 /* This board provides a DMA pool and APIs */
 #define BOARD_DMA_ALLOC_POOL_SIZE 5120
 
+/* This board has 3 DMA channels available for bidirectional dshot */
+#define BOARD_DMA_NUM_DSHOT_CHANNELS 3
+
 /* This board provides the board_on_reset interface */
 
 #define BOARD_HAS_ON_RESET 1

boards/ark/fpv/src/timer_config.cpp

@@ -58,7 +58,7 @@
 constexpr io_timers_t io_timers[MAX_IO_TIMERS] = {
 	initIOTimer(Timer::Timer5, DMA{DMA::Index1}),
 	initIOTimer(Timer::Timer8, DMA{DMA::Index1}),
-	initIOTimer(Timer::Timer4, DMA{DMA::Index1}),
+	initIOTimer(Timer::Timer4),
 };
 
 constexpr timer_io_channels_t timer_io_channels[MAX_TIMER_IO_CHANNELS] = {

boards/ark/pi6x/src/board_config.h

@@ -309,6 +309,9 @@
 /* This board provides a DMA pool and APIs */
 #define BOARD_DMA_ALLOC_POOL_SIZE 5120
 
+/* This board has 4 DMA channels available for bidirectional dshot */
+#define BOARD_DMA_NUM_DSHOT_CHANNELS 4
+
 /* This board provides the board_on_reset interface */
 
 #define BOARD_HAS_ON_RESET 1

boards/holybro/kakutef7/default.px4board

@@ -17,7 +17,6 @@ CONFIG_DRIVERS_IMU_INVENSENSE_MPU6000=y
 CONFIG_DRIVERS_OSD_ATXXXX=y
 CONFIG_DRIVERS_PWM_OUT=y
 CONFIG_DRIVERS_RC_INPUT=y
-CONFIG_DRIVERS_TELEMETRY_FRSKY_TELEMETRY=y
 CONFIG_MODULES_BATTERY_STATUS=y
 CONFIG_MODULES_COMMANDER=y
 CONFIG_MODULES_CONTROL_ALLOCATOR=y
@@ -47,6 +46,6 @@ CONFIG_MODULES_SENSORS=y
 # CONFIG_SENSORS_VEHICLE_AIRSPEED is not set
 # CONFIG_SENSORS_VEHICLE_MAGNETOMETER is not set
 # CONFIG_SENSORS_VEHICLE_OPTICAL_FLOW is not set
-CONFIG_SYSTEMCMDS_DMESG=y
+# CONFIG_SYSTEMCMDS_DMESG is not set
 CONFIG_SYSTEMCMDS_PARAM=y
-CONFIG_SYSTEMCMDS_TOP=y
+# CONFIG_SYSTEMCMDS_TOP is not set

platforms/nuttx/src/px4/nxp/imxrt/dshot/dshot.c

@@ -418,6 +418,21 @@ void up_bdshot_erpm(void)
 }
 
 
+int up_bdshot_num_erpm_ready(void)
+{
+	int num_ready = 0;
+
+	for (unsigned i = 0; i < DSHOT_TIMERS; ++i) {
+		// We only check that data has been received, rather than if it's valid.
+		// This ensures data is published even if one channel has bit errors.
+		if (bdshot_recv_mask & (1 << i)) {
+			++num_ready;
+		}
+	}
+
+	return num_ready;
+}
+
 
 int up_bdshot_get_erpm(uint8_t channel, int *erpm)
 {

platforms/nuttx/src/px4/rpi/rpi_common/include/px4_arch/io_timer.h

@@ -151,9 +151,6 @@ __EXPORT int io_timer_free_channel(unsigned channel);
 __EXPORT int io_timer_get_channel_mode(unsigned channel);
 __EXPORT int io_timer_get_mode_channels(io_timer_channel_mode_t mode);
 __EXPORT extern void io_timer_trigger(void);
-__EXPORT void io_timer_update_dma_req(uint8_t timer, bool enable);
-
-__EXPORT extern int io_timer_set_dshot_mode(uint8_t timer, unsigned dshot_pwm_rate, uint8_t dma_burst_length);
 
 /**
  * Returns the pin configuration for a specific channel, to be used as GPIO output.