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ACRIS Firmware

This directory contains firmware for the AVR MCU. It is targeted at the ATmega168. The ATmega88 won't work because the bootloader is too big.


bld/        - configuration files for build
inc/        - include files
lib/        - library modules
prj/        - projects
Makefile    - rules for making projects from the fw dir   - well, what are you reading?


Projects are located in the prj dir.

bootloader  - ACRIS bootloader (broken due to size issues)
ledctrlr    - main LED controller firmware (getting there)
rftxer      - wireless transmitter module (basic idea down)

test-nrf    - first attempt at wireless communication with an NRF24L01+

bootloader_uart - modified legacy bootloader that communicates over serial
ledctrlr_uart   - modified legacy LED controller firmware, also serial

Project structure

Each project includes:

Makefile    - rules for making the project
config.h    - master configuration file with project-specific rules
pins.h      - project pinout
main.c/h    - main project source   - exactly what you would expect


There are also libraries. In some cases, a single header can be supported by multiple underlying designs. Example: the nrfspi_ module can either be driven by the USART or the SPI module on the AVR.

inc/ - include headers
lib/ - library modules

fn prefix   files       description
__________  __________  __________________________________________________
dbg_        dbg.h       control of board debug LEDs

eeprom_     eeprom.h    reading and writing settings in the EEPROM

flash_      flash.h     flash memory access functions

led_        led.h       action translator for LED array output

ledset_     ledset.h    functions for setting up TLC output buffer

nrf_        nrf.h       driver for NRF24L01+

nrfspi_     nrfspi.h    underlying data transfer layer between MCU and NRF
            nrfspi_spi.c      using HW SPI module
            nrfspi_usart.c    using USART in SPI master mode

tlc_        tlc.h       driver for TLC5940

uart_       uart.h      UART communication layer

uart_printf_    uart_printf.h   retargeting printf for uart output

uart_rb_    uart_rb.h   ring-buffer com layer to make receiving streaming
            uart_rb.c   data easier


The bld directory contains the master rules for building projects.


  1. Fix the wireless bootloader... it's too big for the flash. This probably means an architectural change in reality, but at the very minimum involves statically linking to the end of the app-space flash or something stupid and dangerous like that.

  2. Install a shim between nrf_ and the application layer to allow switching between wireless communication over NRF24L01+ and wired communication over RS-485.

  3. Add optional automatic retransmission support to the NRF driver.

  4. [partial] Update the bootloader to support wireless communication, with automatic retransmission to guarantee a good firmware load.

  5. Come up with a decent scheme for identifying all devices on the network and talking with each one of them (i.e. some kind of auto-discovery). I have some ideas floating around in my head that make use of the multi-pipe features of the Nordic chips.

  6. Add training to startup to determine best communication channels; come up with a way to change network channels on the fly.

  7. Expand transmitter system to support multiple transmitters on a single host to boost throughput. For extra lulz, make some run on the USART and others run on SPI and make the whole architecture event driven.