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Rodeo

sat_chain.h

Generated from the header

This page is rodeo-sdk/common/sat_chain.h — its comments and declarations. To change it, change the header.

This is the engine, and it is pure logic: no UART, no clock, no libDaisy. It decides what frame to send next and makes sense of what comes back; a transport moves the bytes (sat_chain_port.h on the Seed, a simulated ring in common/tests/sat_chain_gtest.cpp). The frame format is sat_frame.h, and the rules are RODEO_SATELLITE_CHAIN_CONTRACT.md (§ numbers below):

  • wait 50 ms after power for the satellites to boot (§6.1), then DISCOVER;
  • SCAN every 4 ms (§6.2), output slots out, input slots back;
  • three bad SCANs in a row: DISCOVER again, up to three times (§5.1);
  • still nothing: find the break by closing the ring one satellite further each time, and keep scanning the satellites before it (§5.2); retry the whole ring every couple of seconds in case it has been fixed.

Controls are addressed by satellite (chain order, from 0) and slot within it. Which control is which parameter is the instrument’s business.

One exchange at a time:

SatChain::Exchange ex;
if(chain.Poll(now_us, ex))   // something to send now
    port.Start(ex);          // ...and later, when it has come back or timed out:
chain.Reply(rx, len, now_us);

SatChain

class SatChain

Members

  • static constexpr int kMaxSatellites = SAT_MAX_SLOTS — one slot each, at most

SatChain::Config

struct Config

Members

  • uint32_t scan_period_us = SAT_SCAN_PERIOD_MS * 1000u
  • uint32_t power_wait_us = SAT_FIRST_DISCOVER_MS * 1000u
  • uint32_t retry_period_us = 2000000u — how often a broken ring is retried whole
  • uint8_t fw_major = 1 — the satellite firmware major this build speaks

SatChain::State

enum class State : uint8_t
  • kPowerWait — waiting for the satellites to boot
  • kDiscover — learning the chain
  • kScan — the whole ring answers
  • kFindBreak — the ring is broken: looking for where
  • kPartial — broken: scanning the satellites before the break
  • kVersion — a satellite runs a firmware major this build doesn’t speak

SatChain::Exchange

struct Exchange

One frame to send, and what to expect back.

Members

  • uint8_t tx[SAT_MAX_FRAME_LEN]
  • uint16_t tx_len
  • uint16_t rx_len — the reply’s exact length; 0: read it from the reply’s header
  • uint32_t timeout_us — give up on the reply after this long

SatChain::Init

void Init(const Config& cfg, uint32_t now_us);

SatChain::Poll

bool Poll(uint32_t now_us, Exchange& ex);

True when a frame should go out now; fills ex. Call often from the main loop. Nothing is sent while a reply is awaited.

SatChain::Reply

void Reply(const uint8_t* rx, size_t len, uint32_t now_us);

The reply to the last exchange: len bytes, or fewer (0 included) when it timed out.

SatChain::GetState

State GetState() const;

SatChain::Satellites

int Satellites() const;

Satellites being scanned: the whole ring, or those before a break.

SatChain::Satellite

const sat_descriptor& Satellite(int i) const;

SatChain::BrokenAfter

int BrokenAfter() const;

A break was found after this many satellites, or -1 if there is none.

SatChain::Changed

bool Changed();

True once after the chain’s layout changes (discovered, grown, broken).

SatChain::GoodScans

uint32_t GoodScans() const;

SCAN replies that came back whole, and those that didn’t.

SatChain::BadScans

uint32_t BadScans() const;

SatChain::Input

sat_slot Input(int i, int s) const;

The slot as last received with a good CRC.

SatChain::Pot

float Pot(int i, int s) const;

A POT slot’s position, 0..1.

SatChain::EncoderSteps

int EncoderSteps(int i, int s);

Encoder detents since the last call, + or -.

SatChain::Pressed

bool Pressed(int i, int s) const;

Whether a button, or an encoder’s push switch, is held now.

SatChain::Presses

int Presses(int i, int s);

Presses since the last call.

SatChain::SwitchPosition

int SwitchPosition(int i, int s) const;

A SWITCH slot’s position index.

SatChain::Fault

bool Fault(int i, int s, uint8_t* code = nullptr, uint8_t* detail = nullptr) const;

True if the slot reports a FAULT; *code and *detail say which (§7).

SatChain::SetLed

void SetLed(int i, uint8_t brightness, uint8_t mode = SAT_LED_STEADY);

A satellite’s LED: brightness 0..255 and a SAT_LED_ mode. Sent with every scan.

SatChain::SetRgb

void SetRgb(int i, int s, uint8_t r, uint8_t g, uint8_t b);

The colour of the RGB LED on satellite i’s slot s, for boards with one per slot (the button bank). Sent with every scan as an RGB slot (§3.2), in place of SetLed’s on slot 0. Colours travel as RGB565.