Firmware

Initialization

• Initialize Kicker(attiny) and FPGA using binary files stored on MBED
  • Compilation for these files is separate from firmware MBED runs
• Initialize any other devices (radio, MPU, etc.)
• Start threads

RTOS (Threads)

• Threads allow us to run multiple segments of code in "parallel"
• MBED only has one core so only one thread executed at once
• RTOS is used to control the running of these threads
• Threads can be running, ready (in queue to be run), or waiting (for some event like a timer or interrupt)

Main

• Watchdog (reset MBED if it doesn't go back to main in certain time)
• Control LEDs (neopixel & LEDs connected to IO Expander)
• Respond to buttons/switches(rotary selector & dip switch)

Other threads

• Console
  • Read and write to serial for the console
  • Commands for console defined in commands.cpp
• Controller
  • Send duty cycles to FPGA to control motor speeds
• Radio
  • Two RX threads, one TX thread (see Radio section)

Radio

• How commands are sent to robot (motor speeds, kick, etc.)
• How information is sent back to the base station (various robot statuses)

CommLink

• Used as hardware abstraction layer to communicate from higher level firmware to radio hardware (through drivers)
• What we use to call functions to get/send data through radio
• Other radio drivers (cc1201 and decawave) are derived from this in order to implement the specific hardware communication
• Runs RX thread waiting for radio interrupts

CommModule

• Used to handle packets being sent and received with radio
• RX/TX queues (as threads) waiting for other threads to put packets in the queue that are ready to be sent or have been received and need to be processed

Shared SPI

• Allows MBED (master) to communicate with multiple devices through same pins
• Devices (slaves) currently used are radio, kicker (ATtiny), and FPGA
• This ensures multiple threads aren't trying to communicate on these shared lines all at once

Hardfault Handler

• Written in assembly to call function when the mbed hard faults (crashes)
• Used to print out information to console useful for debugging

FPGA (verilog)

• FPGA is programming logic gates which allows for many parallel operations
• Reads in hall sensors for motors
  • Used to determine which phase to power to keeps motors running
• Gets encoder values for how fast motor is spinning
  • Given number of encoder steps passed in period of time
  • This value can be read by MBED over SPI
• Powers correct phases for motors (by sending signals to motor drivers)
  • Powers the next phase after the current phase given by hall sensors
  • Powers the motors using the duty cycle sent from the MBED
    • Adjusting the duty cycle allows us to control motor speeds
• Acts as SPI slave to receive motor speeds from MBED and has second SPI communication where it acts as SPI master to communicate with motor drivers
• Pin configurations found in robocup.ucf

Base Station

• MBED with only radio connected
• Uses MBED serial lines to communicate with computer running soccer
• Commands are sent from soccer to base station then to each robot
• Base station recieves replies back from robots then sends this to soccer