app_link.h File Reference

Receive side of the ACwing Pilot link (HANDOVER_FW.md §2 and §6). More...

#include <stdint.h>

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Data Structures
struct	appl_cmd_t
struct	appl_rc_t

Macros
#define	APPL_CMD_MAX   20u
#define	APPL_QUEUE_LEN   16u
	power of 2, >= 8 required by the handover

Functions
void	appl_reset (void)
void	appl_on_cmd_write (const uint8_t *data, uint16_t len, uint32_t now_ms)
void	appl_on_connect (void)
void	appl_on_disconnect (void)
int	appl_pop (appl_cmd_t *out)
	1 if a command was taken
uint32_t	appl_queue_dropped (void)
uint8_t	appl_ever (void)
	1 once any CMD frame arrived
uint32_t	appl_last_ms (void)
	time of the last CMD frame
uint8_t	appl_link_down (void)
	GAP disconnected since then
uint32_t	appl_silence_ms (uint32_t now_ms, uint32_t down_floor_ms)
	Silence seen by the failsafe: now - last CMD frame, at least 'down_floor_ms' while the link is reported down; UINT32_MAX if nothing ever arrived.
int	appl_rc_read (appl_rc_t *out, uint32_t *t_ms)
	Latest RC values and their arrival time.

Detailed Description

Receive side of the ACwing Pilot link (HANDOVER_FW.md §2 and §6).

The BLE CMD write callback (HCI user-event thread of the stack) calls appl_on_cmd_write() and NOTHING else happens in that context:

• the arrival time is stored from a monotonic hardware tick (one aligned 32-bit store: atomic on Cortex-M, no lock);
• RC (0x11) values are stored behind a sequence counter (seqlock): the reader in the flight core never waits, it retries or keeps the previous values;
• HEARTBEAT (0x10) only refreshes the time;
• every other v2 opcode (>= 0x10) is copied (<= 20 bytes) into a single-producer single-consumer queue drained by the AppTask. Legacy 0x01/0x02 are still handled inline by tlm_ble_on_command().

Only CMD frames refresh the app-link time: connection events, CCCD writes, notifications sent or link-layer keep-alives do not (they never call this). A GAP disconnection only marks the link down, which can make the failsafe start earlier, never later (appl_silence_ms()).

Host-testable: no HAL, no RTOS.

Definition in file app_link.h.

Macro Definition Documentation

APPL_CMD_MAX

#define APPL_CMD_MAX   20u

Definition at line 29 of file app_link.h.

APPL_QUEUE_LEN

#define APPL_QUEUE_LEN   16u

power of 2, >= 8 required by the handover

Definition at line 30 of file app_link.h.

Function Documentation

appl_reset()

void appl_reset

(

void

)

Definition at line 32 of file app_link.c.

References s_down, s_ever, s_head, s_last_ms, s_qdrop, s_rc, s_rc_ever, s_rc_ms, s_rc_seq, and s_tail.

appl_on_cmd_write()

void appl_on_cmd_write	(	const uint8_t *	data,
		uint16_t	len,
		uint32_t	now_ms
	)

Definition at line 41 of file app_link.c.

References APPL_BARRIER, APPL_CMD_MAX, APPL_QUEUE_LEN, appl_cmd_t::b, appl_rc_t::buttons, appl_cmd_t::len, appl_rc_t::pitch, PV2_OP_HEARTBEAT, PV2_OP_RC, pv2_rd_i16(), QMASK, appl_rc_t::roll, s_down, s_ever, s_head, s_last_ms, s_q, s_qdrop, s_rc, s_rc_ever, s_rc_ms, s_rc_seq, s_tail, appl_rc_t::thr, and appl_rc_t::yaw.

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appl_on_connect()

void appl_on_connect

(

void

)

Definition at line 81 of file app_link.c.

appl_on_disconnect()

void appl_on_disconnect

(

void

)

Definition at line 82 of file app_link.c.

References s_down.

appl_pop()

int appl_pop

(

appl_cmd_t *

out

)

1 if a command was taken

Definition at line 85 of file app_link.c.

References APPL_BARRIER, QMASK, s_head, s_q, and s_tail.

Referenced by commands().

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appl_queue_dropped()

uint32_t appl_queue_dropped

(

void

)

Definition at line 96 of file app_link.c.

References s_qdrop.

appl_ever()

uint8_t appl_ever

(

void

)

1 once any CMD frame arrived

Definition at line 99 of file app_link.c.

References s_ever.

appl_last_ms()

uint32_t appl_last_ms

(

void

)

time of the last CMD frame

Definition at line 100 of file app_link.c.

References s_last_ms.

appl_link_down()

uint8_t appl_link_down

(

void

)

GAP disconnected since then

Definition at line 101 of file app_link.c.

References s_down.

appl_silence_ms()

uint32_t appl_silence_ms	(	uint32_t	now_ms,
		uint32_t	down_floor_ms
	)

Silence seen by the failsafe: now - last CMD frame, at least 'down_floor_ms' while the link is reported down; UINT32_MAX if nothing ever arrived.

Definition at line 103 of file app_link.c.

References s, s_down, s_ever, and s_last_ms.

Referenced by app_link_failsafe(), and calibration().

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appl_rc_read()

int appl_rc_read	(	appl_rc_t *	out,
		uint32_t *	t_ms
	)

Latest RC values and their arrival time.

Returns 1 with a consistent copy, 0 if no RC ever arrived (out untouched).

Definition at line 112 of file app_link.c.

References APPL_BARRIER, s_rc, s_rc_ever, s_rc_ms, and s_rc_seq.

Referenced by build_checks(), and update_sticks().

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