upkie::cpp::spine Namespace Reference

Inter-process communication protocol with the spine. More...

Classes
class	AgentInterface
	Memory map to shared memory. More...
class	Spine
	Loop transmitting actions to the actuation and observations to the agent. More...
class	StateMachine
	Spine state machine. More...

Enumerations
enum class	Request : uint32_t {   kNone = 0 , kAction = 1 , kStart = 2 , kStop = 3 ,   kError = 4 }
	Request flag used for shared-memory inter-process communication. More...
enum class	State : uint32_t {   kSendStops = 0 , kReset = 1 , kIdle = 2 , kStep = 3 ,   kShutdown = 4 , kOver = 5 }
	States of the state machine. More...
enum class	Event : uint32_t { kCycleBeginning = 0 , kCycleEnd = 1 , kInterrupt = 2 }
	Events that may trigger transitions between states. More...

Functions
void	allocate_file (int file_descriptor, int bytes)
	Allocate file with some error handling. More...
constexpr const char *	state_name (const State &state) noexcept
	Name of a state. More...

Variables
constexpr size_t	kMebibytes = 1 << 20
	Number of bits in one mebibyte.
constexpr unsigned	kNbStopCycles = 5
	When sending stop cycles, send at least that many.

Detailed Description

Inter-process communication protocol with the spine.

Main control loop between agents and actuators.

Design notes: one alternative was a proper FSM with a clear distinction between states (what the spine is doing) and transitions (agent requests, spine replies, etc.). This could have allowed more granularity, such as the spine doing nothing (instead of sending stops) when it is idle, however at the cost of more complexity. We choose to go for the simpler (riskier) version where both agent and spine directly manipulate the agenda.