dynalite-ddrc810: A C++ repository from aliffers

Dynalite DDRC810 Emulation Library
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This library is how I use it on my network that is largely controlled by a
Genisys Master home automation controller.  It does work directly on DyNet
OpCodes, and can be easily modified to suit other environments.  I am happy
to answer questions as to why I did what, but not rewrite it to suit other
networks.

This library receives Dynalite OpCodes in the form of a byte array that is as
if it were listening directly on thye Dynalite bus, and pretends that it is a
DDRC810 8 channel relay.  It uses the I2C_RL8xxM Arduino library to control
a relay board over I2C.  This makes it possible to add up to 8 relay boards to
a single Arduino and have them behave as 8 separate DDRC810 controllers,
giving a total of 64 channels.

To use the library, include the library in your sketch:
#include <Dynalite_DDRC810.h>

Initialisation
--------------
This is probably the most confusing part, and it could probably be done in a
more optimised way, but it's designed for speed in operation as someone turning
on a channel on Dynalite doesn't want to wait 3 seconds for the action to
occur.  Everything is in byte arrays so that bitwise operators (NOT/AND/OR/XOR)
can be used, which typically use one or two CPU cycles to evaluate.

The DDRC810 class is initialsed using the begin() function with 7 values.

id
A byte that is the phyisical dynalite id of the controller, eg 0x04.

addr
The I2C address of the I2C_RL8xxM relay controller.  There's a separate repo
for this library.

respond
A function pointer to a function, defines as "void fn(byte*)" which expects
an 8 byte array, that is an OpCode.  This function is called by the class when
it receives an OpCode that requires it send a message back onto the Dynalite
bus (request channel level for example).  This class will not calculate the
checksum in the 8th byte of the OpCode.  It expects that whatever function is
writing to DyNet takes care of that.

area
This is an array of bytes where the index of the array is the DyNet area number
and the value is a byte indicating which channels on the I2C_RL8xxM is a member
of that area.  The first values is always zero, since area numbers start with 1.
The area number form the OpCode is used to directly access the area array, with
a "-1" to save on cpu cycles and increase speed.
For example, initialising with { 0x00, B11100001, B00000010 } means that relay
1, 6, 7 and 8 are in channel 1 and relay 2 is in area 2.

areas
Total number of areas; should be the number of elements in the area array.

channel
Same principle as the area array. However, since channels are per area and not
global, and zero based, there's going to be a high number of relays in channel
zero.  The DyNet OpCode to turn on a channel is always channel X in area Y, so
to determine the relay used we use channel[X] & area[Y] and send that an on/off
command in the I2C_RL8xxM.

channels
Number of elements in the channel array.

Functions
---------
One and only function is process, which expects an 8 byte DyNet OpCode in the
form of an 8 byte array.

It will resond to a physical (5C) request, which is used to turn an entire
DDRC810 controller on/off, or logical requests that make sense for a DDRC810
relay controller.  Channel level is always given as 0 or 255 for off and on.
Setting a chanel level is treated as 0% = off and anything greater than 0% is
on .  Fade time is ignored; it's a relay.

My system is using a Genisys master home automation controller, which defines
two presets that effectively mean "off" and they're taken care of as such in
this.  This may not be suitable for all environments.

The actions to perform on various opcodes is one one big switch() statement
that can be easily tweaked to do anything else.
aliffers/dynalite-ddrc810
