Software

High-Level Software Architecture

The software of NIMBY is modularized into a hierarchical structure, with a high-level hierarchical state machine (HSM) module handling the high-level logic and reasoning, and low-level modules that handle critical functions including driving motors, encoder feedback, SPI communications, sensor input capture (IC), PWM output, etc. Each module is implemented in event-driven C on the PIC32 microcontroller, adapting Prof. Ed Carryer's Events and Services Framework. The functionality is distributed among the modules as follows:

Leader PIC High-Level Logic

RobStrat_TopLevelSM: Handles transitions between Idle, MainGame, SuddenDeath
RobStrat_IdleSM: Maps button inputs to toggle between game modes and start game
RobStrat_MainGameSM: Implements logic sequence for a full tournament game
RobStrat_SuddenDeathSM: Implements logic sequence for sudden-death game mode
RobStrat_Init: Initialization sequence to collect first puck, determine side-of-field by homing onto IR beacons, and align to the tape line
RobStrat_TapeFollowing: Responds to tape sensor signals to implement tape-following logic
RobStrat_TreePuck: Commands sequence to harvest tree of ACORNs and shoot them to the opponent's field
RobStrat_TreeCounting: Tracks of the number of trees we've harvested for ACORNs
RobStrat_RealignToTape: Realigns to tape after the first tree interaction
RobStrat_PatrolFreePuckSearch: Sweeps field along center tape line for loose pucks during free-puck stage
RobStrat_TestHarnessService [Test Harness]: Injects events into high-level SM from keyboard input

Leader PIC Low-Level Modules

IRService: Configures interrupt-driven IC of IR beacon signal to measure signal frequency and post events when valid beacon detected
LeaderSPICommSM: Handles two-way SPI communications with Follower PIC32
OnOffService: Event checker for button long-press and short-press events, handles LED effects (On, Off, Slow Flash, Fast Flash)
PIC32_SPI_HAL: Hardware-Abstraction Layer for SPI communication on PIC32
ServoAndPuckSensorsService: Handles PWM output and interrupt-driven IC for frequency analysis of reflected IR signal off of puck for puck sensor, AND generating event-driven servo control signal (both functionality based off of same hardware timer)
TapeSensorService: Posts events when tape sensor detects or loses sight of tape
TestDrivetrainSPIService [Test Harness] : Test drivetrain through LeaderSPI

Follower PIC Low-Level Modules

DCService: Set PWM signals to control the drivetrain motors according to high-level commands (eg drive forward, curve right, etc)
EncoderPIDFSM: Process quadrature encoder signal to apply PI control signal to the motors given a desired goal speed or position for drive turns, drive straights, etc
FollowerSPICommService: Handles two-way SPI communications with Leader PIC32, including interrupt-driven logic to maintain a buffer of valid messages to transfer upon request from the Leader
IntakeService: Handles direction and PWM motor control signals to drive intake motors through the integrated H-bridge motor control circuit
PIC32_SPI_HAL: Hardware-Abstraction Layer for SPI communication on PIC32