Introduction
------------

This is a basic DCC command station for the Raspberry Pi. It generates
output suitable for feeding into an L298N or similar H-bridge. I've
successfully used it with one like this:

http://www.ebay.co.uk/itm/Dual-H-Bridge-DC-Stepper-Motor-Drive-Controller-Board-Module-Arduino-L298N-/390535254940

(if you try it with something like this, bear in mind that there is no
short circuit/overcurrent detection)

Building and running
--------------------

To build, run make.

Connect the pins as follows:

	Raspberry Pi			L298N board
	-------------------------------------------
	GPIO0 (pin 3 on the header)	IN1
	GPIO1 (pin 5)			IN2
	GPIO4 (pin 7)			ENA
	GND (eg pin 6)			GND

Run gpiodcc (as root, or with sudo), and telnet to localhost port 4303. You
should be able to issue the following commands:

SET PROTOCOL SRCP 0.8.3
SET CONNECTIONMODE SRCP COMMAND
GO

Then, to initialise a locomotive decoder

INIT 1 GL <addr> N 1 128 <functions>
	<addr> = loco address
	<functions> = number of functions, eg 1 for FL only

And, to set speed/direction/function state

SET 1 GL <addr> <dir> <speed> <max speed> <fl> <f1> <f2>...
	<addr> = loco address
	<dir> = 0 (backwards), 1 (forwards), 2 (emergency stop)
	<speed> = 0 (stop) to <max speed>
	<max speed> = a number which defines the top speed. eg, 100 makes
		<speed> a percentage
	<fl> = status of FL (or function 0). 1 = on, 0 = off
	<f1>, etc = status of function. Only supply as many as there are
		functions defined in INIT; any others will be ignored

Example:

INIT 1 GL 5 N 1 128 1
	- define a locomotive at (short) address 5, 128 speed steps, 1
	function

SET 1 GL 5 1 50 100 1
	- forwards at 50% speed with the front light on

Note
----

This code works with JMRI, and SRCP Client on Android. Other things (such as
Rocrail) have not been tried. It is a very incomplete implementation of
SRCP

The supported loco types are very limited for the moment:
	Only 128 speed steps
	Only 5 functions (FL, F1-F4)
	Only short addresses

There is currently no support for programming (either on a programming track
or the main), or any form of accessory decoder

This code should be regarded as experimental and incomplete