roelandkluit/loconet

An embedded Loconet interface library for Arduino family microcontrollers

Overview

The EmbededLocoNet Library provides functions that manage the sending and receiving of LocoNet packets.

As bytes are received from the LocoNet by an interrupt driven handler, they are stored in a circular FIFO buffer. The LocoNet.receive() method returns the head packet from the buffer, or NULL if no valid packets have arrived.

When packets are sent successfully, by default they are also appended to the circular receive buffer so they can be handled in the same manner as if they had been received from another device.

It maintains statistics about the transmission and reception of packets. Also, it discards any invalid packets it receives, incrementing an RxErrors statistic accordingly.

Hardware Resource Dependencies

This library uses TIMER1 & ICP (UNO) and/or TIMER5 and ICP5 (MEGA) resources and associated interrupt handler hooks. On the STM32, it uses TIM2 and the EXTI10-15 interrupts handler hooks. On the ESP8266, the implementation uses TIMER1 and associated interrupt handler hooks.

Of the AVR "mega" and "tiny" range of microcontrollers, this library only works on those that have an Input Capture Unit (ICP) associated with a 16-Bit Timer/Counter.

It's known to work with:

• UNO (ATmega328)
• MEGA (ATmega2560)
• Leonardo, LeoStick, Arduino Pro Micro (ATmega32U4)
• Various AVRTiny Boards (ATTiny84, ATTiny84A, ATTiny841)
• Blue Pill (STM32F1 w/ libopencm3 and Arduino Stubs)
• NodeMCU v1.0 (ESP8266 core for Arduino)

As of 2020-03-28 - Hans Tanner added the capability to change the polarity of the Rx and Tx electrical signal (depending on your circuitry) in the utility/ln_config.h file. The is controlled using the two #defines LN_SW_UART_RX_INVERTED and LN_SW_UART_TX_INVERTED

Contributing

Update the version in two places:

1. library.properties - used by the Arduino IDE via https://github.com/arduino/library-registry#adding-a-library-to-library-manager
2. library.json - used by PlatformIO, see https://docs.platformio.org/en/latest/manifests/library-json/index.html

Releasing

Arduino IDE: add a tag or GitHub Release matching the version number in library.properties. See the documentation.

For PlatformIO, see documentation about publishing.

IMPORTANT

Some message formats used in this code are Copyright Digitrax, Inc. and/or Elektronik GmbH and are used with permission as part of the MRRwA project. That permission does not extend to uses in other software products. See the LICENSE file for more information.