Table of Contents

rocNET Protocol

Inhoud → Central Stations → rocNET


This is an binary Open Source protocol intended for communication between two or more, in a peer to peer network, hardware units.
Software stubs will be made available in C. The C source can, partly, also be used as base for embeded software. (PIC/Atmel)

Work in progress, can change any moment, open for any comment, advice and help.


Features


Masterless Network

The idea is to build a network of two or more units of operation.
There are different types of units:

All should have their own unique ID which is used as sender/receipient parameter in the header.
The unit who is processing all messages and sends a lot of them can be entitled to be the master of the network, but in fact it is only a player in the game. So in the case of Rocrail the computer running this software could be seen as the master.


Setup

RocNET has a dedicated node for setting up the communication:

Only UDP is supported.
Default settings:


Packet Format

Header
network receipient sender action data
netid rcptH rcptL sndrH sndrL group code length n data bytes



Packet Content

Network ID

To group units in a large system. Leave zero if there is only one active network.

Receipient

Every unit in the network has its own ID.
If left to zero all units must evaluate the packet. This can be of use for queries to see which devices are available.

Sender

The ID of the sender unit. Rocrail Server default ID is 1.
A value of "0" means undefined.

Action

If the action needs an address it will be provided in the first two bytes of data part. (Extended format)

Length

Netto number of following data bytes.

Data

The variable part of the packet which is action dependent.
The length may be set to zero if no further information is needed for the given action.


Network ID

bit 7 6 5 4 3 2 1 0
function 8 bits ID (0-255)

Zero is for all networks.

Address/ID High/Low

bit 7 6 5 4 3 2 1 0
function 8 bits ID (0-255)
Calculating the Address/ID
ID = idL + idH * 256


Group

bit 7 6 5 4 3 2 1 0
function 8 bit group code (0-255)


Code

bit 7 6 5 4 3 2 1 0
function 3 bit type (0-7) 5 bit code (0-31)
Type

If the type is an event or reply, no real I/O action should be taken on the specified address; mostly the I/O with this address signals a state change.

Length

bit 7 6 5 4 3 2 1 0
function number of data bytes (0-255)


Data

bit 7 6 5 4 3 2 1 0
function 8 data bits (0-255)



Groups

Code Description Remark
1 Command Station Command Station
2 Mobile decoders Locomotives and functions
3 Stationary decoders Multiport for inputs and outputs
4 Programming mobile DCC CVs
5 Programming stationary Including command stations
6 GP Data transfer General purpose data transfer between modules
7 Clock Fast clock
8 Sensor Position determination


Command Station

Actions

act description data 1 reply data 1 reply data 2
0 NOP 0
1 query status
2 track power 0 = off, 1 = on status
3 halt status
4 version versionH versionL
5 PT on/off on/off on/off


The address is optional and can be used to point at a single booster.

Status
7 6 5 4 3 2 1 0
0 PT busy idle power


Mobile

Actions

request reply
code description data 1 data 2 data 3 data 1 data 2 data 3 data 4
0 NOP 0
1 setup protocol number of functions
2 velocity³ 0…255 direction¹ lights¹
3 function F-Group F1-F8²
4 query code sub-code code sub-code response depends on code


¹) Leave unchanged if bit 7 is not set in this byte.
²) Lights if F-Group = 0.
³) Alternatively the velocity can be send with only one byte in which bit 7 controls the direction and the velocity range ist 0…127.

Protocol Type

Code Type Description
0 256 256 step interpreted
1 DCC 28 NMRA DCC with 28 speed steps
2 DCC 128 NMRA DCC with 128 speed steps
3 DCC 14 NMRA DCC with 14 speed steps


Examples

Stop all locos send by the Rocrail server:
netid rcptH rcptL sndrH sndrL group code length velocity direction lights
0 0 0 0 1 2 2 3 0 0 0
all all all srvr srvr mobile velocity

Binary representation: 

00 00 00 00 01 02 02 03 00 00 00

Direction and lights are left unchanged because bit 7 of both bytes are not set.


Set velocity by the Rocrail server:
netid rcptH rcptL sndrH sndrL group code length velocity direction lights
0 1 35 0 1 2 2 3 48 129 128

Binary representation: 

00 01 23 00 01 02 02 03 30 81 80


Stationary

Actions

code description data 1 data 2 data 3 reply data 1 reply data 2 reply data 3 reply data 4
0 NOP 0
1 single port 0,1 (off,on) protocol delay status
2 port pair 0,1 (close,throw) address is first port of pair protocol delay status
3 multi port port mask 0…255 where address is offset protocol status n
4 query single port addrH addrL status
5 query port pair addrH addrL status
6 query multi port addrH addrL status n
7 report¹ addrH addrL status1 status2

¹) All connected stationary decoders should report status if receipient is set to zero.

Programming

For programming stationary decoders the address represents the module address.

Actions

code description data 1 data 2 data 3 data 4 reply data 1 reply data 2 reply data 3 reply data 4
1 write registerH registerL valueH valueL registerH registerL valueH valueL
2 read registerH registerL registerH registerL valueH valueL
3 copy destH destL data n ack


Clock

Actions

code description data 1 data 2 data 3 data 4 data 5 data 6 data 7 data 8
1 set yearH yearL month day hour minutes seconds div
2 sync yearH yearL month day hour minutes seconds div


Sensor

Actions

code description data 1 data 2 data 3
1 report addrH¹ addrL¹ status

¹) Address of the reporting loco.
The sensor ID is set in the header; Sender.