public:cbuspublic:start
Differences
This shows you the differences between two versions of the page.
Both sides previous revisionPrevious revisionNext revision | Previous revisionLast revisionBoth sides next revision | ||
public:cbuspublic:start [2020/01/22 15:26] – [The messaging scheme.] grovenor | public:cbuspublic:start [2020/01/22 19:17] – [CBUS Documentation] grovenor | ||
---|---|---|---|
Line 1: | Line 1: | ||
===== CBUS - A universal layout control system ===== | ===== CBUS - A universal layout control system ===== | ||
- | [[public: | + | |
- | [[public: | + | |
[[: | [[: | ||
==== Introduction ==== | ==== Introduction ==== | ||
- | CBUS is a Layout Control System | + | CBUS is a Layout Control System |
- | cbus.php and cbus2.php | + | * **[[https:// |
+ | * **[[https:// | ||
+ | A complete description of CBUS including the full specification and implementation notes is contained in the ' | ||
+ | | ||
- | {{ http:// | + | ===== CBUS Documentation |
- | ===== CBUS in Brief ===== | + | This is the public view of CBUS and does not include MERG Technical Bulletins (TBs) or links to any other MERG Copyright material which is available only to members. |
- | This is a short overview, mostly useful | + | |
+ | [[developerguide|CBUS Developers' | ||
+ | This Guide is intended for those with technical knowledge wishing to develop additional hardware, software and firmware for use with CBUS. It also provides all the technical background and information to enable a better understanding of how CBUS works, along with the rationale for our choices | ||
+ | |||
+ | [[jmriacccmd|Commanding Accessory Decoders using CANCMD & JMRI]] | ||
+ | This description shows how to use CBUS events to operate DCC accessory modules via the CANCMD. | ||
- | CBUS is a local area bus designed for model railways and it is used for the control of layout accessories and DCC trains. The message is entirely self contained and independent of any transport used. It is currently specified to run over [[wp> | ||
- | A CBUS installation consists of a number of ' | ||
- | In situations where the Producer / Consumer model is inappropriate, | ||
- | ===== Identifiers ===== | ||
- | - **Nodes** are the basic unit of CBUS, and each is usually implemented on one PCB. Node-ids are 16-bit, and are assigned by the user. | ||
- | - **Event** messages are sent by ' | ||
- | * Short-event: | ||
- | * Long-event: 32-bit, made up of the concatenation of a node-id and a 16-bit event# | ||
- | * They are distinguished by the opcode of the message. | ||
- | ===== Message Formats ===== | ||
- | | ||
- | Where the opcode informs the receiving node what to do, using the data as necessary. | ||
- | There are many opcodes, including: | ||
- | - On-Events and Off-Events | ||
- | - Train control, including programming | ||
- | - Node configuration | ||
- | Long Event format is: { opcode, [node-id(2).event# | ||
- | Where the concatenation [node-id.event# | ||
- | Short Event format is: { opcode, node-id(2), device#(2) }, | ||
- | Where node-id and device# are independent. The device# is considered a ' | ||
- | More than one node can send this event, e.g. throttles, and it will have the same effect. | ||
- | By convention, device#s 1-9999 denote ' | ||
- | and device# 10000 the `Start-of-Day' | ||
- | | ||
- | The reason for this partition is that CABs can send short events up to 9999 and it would not be | ||
- | advisable for these to clash with sensor events by mistake. | ||
| | ||
===== Tools: ===== | ===== Tools: ===== | ||
Line 50: | Line 32: | ||
* **SSI** (Solid State Interlocker) from [[http:// | * **SSI** (Solid State Interlocker) from [[http:// | ||
- | ===== Implementation Notes ===== | ||
- | |||
- | * CBUS operates over CAN at 125kbps. | ||
- | * CAN is bidirectional and has built-in error correction and message re-send. | ||
- | * CBUS CAN frames have an 11-bit header and an 8-byte data-part. | ||
- | * The data-part carries the CBUS message. | ||
- | * The header must be unique, and this is ensured by including the 1 byte CAN-ID assigned to the sending node. | ||
- | * The CAN-ID is retained by the node, moving it to a new layout may cause a CAN-ID conflict. | ||
- | * In SLiM mode, the node-id is set by switches, and the CAN-ID is set equal to the low-byte of the node-id. | ||
- | * In FLiM mode, if the node does not have a CAN-ID, one is automatically obtained by self-enumeration: | ||
- | * NB: New modules //must// be introduced to the bus one at a time. | ||
- | * The CAN-ID may be re-assigned: | ||
- | * CBUS uses 29-bit header CAN messages for bootloading. | ||
- | * A complete description of CBUS including the full specification and implementation notes is contained in the ' | ||
- | | ||