U.S. patent application number 11/331868 was filed with the patent office on 2006-06-01 for multiple device communications.
This patent application is currently assigned to American Standard International Inc.. Invention is credited to Robert M. Swanson, Joel C. Vanderzee.
Application Number | 20060114824 11/331868 |
Document ID | / |
Family ID | 24969683 |
Filed Date | 2006-06-01 |
United States Patent
Application |
20060114824 |
Kind Code |
A1 |
Vanderzee; Joel C. ; et
al. |
June 1, 2006 |
Multiple device communications
Abstract
A communications protocol for a communications bus wherein
messages are transmitted to a plurality of devices communicating by
means of a bus. Each message includes a unique code indicating the
end of the message and that same unique code triggers a transfer of
communications control to another device of the plurality of
devices.
Inventors: |
Vanderzee; Joel C.; (La
Crosse, WI) ; Swanson; Robert M.; (La Crosse,
WI) |
Correspondence
Address: |
William O'Driscoll - 12-1;Trane
3600 Pammel Creek Road
La Crosse
WI
54601
US
|
Assignee: |
American Standard International
Inc.
|
Family ID: |
24969683 |
Appl. No.: |
11/331868 |
Filed: |
January 17, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09738834 |
Dec 15, 2000 |
7020156 |
|
|
11331868 |
Jan 17, 2006 |
|
|
|
Current U.S.
Class: |
370/229 ;
370/445; 370/451; 370/462 |
Current CPC
Class: |
H04L 12/417 20130101;
G06F 13/42 20130101 |
Class at
Publication: |
370/229 ;
370/462; 370/451; 370/445 |
International
Class: |
H04J 3/02 20060101
H04J003/02; H04L 12/403 20060101 H04L012/403; H04L 12/413 20060101
H04L012/413; H04L 12/26 20060101 H04L012/26; H04L 12/42 20060101
H04L012/42; H04L 1/00 20060101 H04L001/00 |
Claims
1. A communications system using a communications protocol for a
communications bus wherein messages are transmitted to a plurality
of devices communicating by means of a bus wherein each message
includes a unique code indicating the end of the message and
wherein that same unique code triggers a transfer of communications
control to another device of the plurality of devices.
2. (canceled)
3. (canceled)
4. (canceled)
5. (canceled)
6. (canceled)
7. (canceled)
8. (canceled)
9. (canceled)
10. (canceled)
11. (canceled)
12. (canceled)
13. (canceled)
14. (canceled)
15. (canceled)
16. (canceled)
17. (canceled)
18. (canceled)
19. (canceled)
20. (canceled)
21. The communications system of claim 1 wherein the transfer of
communications control triggered by the unique code is an inherent
change in control of the communications bus.
22. The communications system of claim 21 further including means
for transmitting the messages in a round robin format.
23. The communications system of claim 22 further including means
for responding to the unique code as an end of transmission handoff
allowing either sequential or non-sequential changes in the round
robin format.
24. The communications system of claim 23 wherein the unique code
is a single byte.
25. The communications system of claim 24 wherein the plurality of
devices are arranged into a sequence order wherein each device of
the plurality of devices has a sequence identifier providing both
an identity and a place in the sequence order and wherein the place
in the sequence order is linked with the device identity.
26. The communications system of claim 25 wherein the unique code
is detected by low level hardware, low level software, or low level
firmware.
27. A communication system comprising: a plurality of devices; a
communications bus operably connected to the plurality of devices
and communicating therewith; a communications protocol for the
communications bus; and a plurality of messages being transmitted
over the communications bus to and from the plurality of devices
and in accordance with the communications protocol; wherein each
message of the plurality of messages is transmitted in a round
robin format and wherein each message includes an end of
transmission handoff allowing either sequential or non-sequential
changes in the order of the round robin format.
28. The communication system of claim 27 wherein the end of
transmission handoff includes a unique termination code.
29. The communication system of claim 28 including means for
indicating an end of the message and means for triggering a
transfer of communications control to another device of the
plurality of devices.
30. The communication system of claim 29 wherein the unique code is
detected by low level hardware, low level software, or low level
firmware.
31. A method of communicating in a communication system comprising
the steps of: providing a plurality of devices; operably and
communicatively connecting a communications bus to the plurality of
devices; providing a communications protocol for the communications
bus; transmitting messages in accordance with the communications
protocol over the communications bus to and from the plurality of
devices in a round robin format; and allowing either sequential or
non-sequential changes in the order of the round robin format by
means of an end of transmission handoff contained in each
message.
32. The method of claim 31 including the further steps of
indicating an end of the message by means of a unique code and
triggering a transfer of communications control to another device
of the plurality of devices by means of that unique code.
33. The method of claim 32 wherein the transfer of communications
control triggered by the unique code is an inherent change in
control of the communications bus.
34. The method of claim 33 including the step of forming the unique
code as a single byte.
35. The method of claim 34 including the steps of arranging the
plurality of devices into a sequence order wherein each device of
the plurality of devices has a sequence identifier providing both
an identity and a place in the sequence order and linking the place
in the sequence order with a device identifier.
36. The method of claim 31 including the steps of arranging the
plurality of devices into a sequence order wherein each device of
the plurality of devices has a sequence identifier providing both
an identity and a place in the sequence order and linking the place
in the sequence order with a device identifier.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention provides simple, fast, efficient and
flexible communications apparatus, method and protocol between a
plurality of electronic devices communicating over a common medium
in a communications system.
[0002] Prior designs and existing communications apparatus and
methods have distinct drawbacks. Some use master-slave protocols
that are simple but inefficient. Some use multiple access protocols
that allow collisions requiring either complex hardware or
software. Some use token passing protocols that are both
inefficient and complex. Operations in either or both master/slave
or peer-to-peer communications modes are desirable over an extended
product lifetime.
SUMMARY OF THE INVENTION
[0003] It is an object, feature and advantage of the present
invention to avoid the problems and restrictions present in prior
designs and available industry communications protocols.
[0004] It is an object, feature and advantage of the present
invention to provide operation in either or both master/slave and
peer-to-peer communications modes over an extended product
lifetime.
[0005] It is an object, feature and advantage of the present
invention to provide simple, automatic bus control sharing between
devices. It is a further object, feature and advantage of the
present invention to include the capability to add bus control
features to all devices to allow master-less operation.
[0006] It is an object, feature and advantage of the present
invention to provide a communications protocol where a unique byte
code is detected by low level hardware, firmware or software to
identify the end of one device's message.
[0007] It is a further object, feature and advantage of the present
invention that the unique byte code, upon detection, cause an
inherent change in bus control. It is a further object, feature and
advantage of the present invention that the use of a simple byte
code accomplishes a sequence of bus control transfers with only a
single byte and minimum bus timing needs being met.
[0008] It is an object, feature and advantage of the present
invention to provide a communications protocol that is simple. It
is a further object, feature and advantage of the present invention
that that bus control transfers use a simple mechanism requiring
only the interpretation of an eight bit code and sequential action
based on the operation of a typical UART. It is a further object,
feature and advantage of the present invention that the protocol be
efficient in requiring little overhead for bus control
requirements. It is a still further object, feature and advantage
of the present invention that the protocol be fast and transfer bus
control to each device after minimal delay. It is another object,
feature and advantage of the present invention that the protocol be
flexible in allowing very simple functions and messages to be
constructed using minimal microcomputer resources while also
allowing more complex messages provided by computers with more
resources. It is another object, feature and advantage of the
present invention that master/slave and peer-to-peer operation
coexist within a common communications protocol. It is a further
object, feature and advantage of the present invention that polling
can be implemented within that protocol.
[0009] The present invention provides a device communications. The
device communications comprises: a plurality of communicating
devices; a communications media communicably connecting the
plurality of devices; and a sequential identifier for each of the
plurality of devices. The identifier provides a unique identity for
each device and provides a sequence order for all of the plurality
of devices. The device communications also comprises: a unique
code; and a protocol wherein each device transmits the unique code
on the communications media in the sequence order if the device has
nothing to report, transmits the sequence identifier of another
device followed by data followed by the unique code if the device
has information to report, and transmits the sequential identifier
of another device followed by the unique code if the transmitting
device desires to change out of sequence to a different device in
the sequence order.
[0010] The present invention also provides a method of
communications for a communications bus communicably connecting a
plurality of communications devices. The method comprising the
steps of: assigning an identifier and a sequence order to each of
the multiplicity of devices; transmitting, continuously and in
sequence order, a message on the bus from each of the multiplicity
of devices; and terminating each message with a unique code. The
message comprises the unique code alone if the device has no other
message to transmit. The message comprises the identifier for
another device and the unique code if the transmitting device
desires to move elsewhere in the sequence order. The message
comprises the identifier for another device, data and the unique
code if the transmitting device has a report to make.
[0011] The present invention further provides a method of
communicating between a plurality of devices communicably connected
by a communications medium. The method comprising the steps of:
sequencing the plurality of devices into a sequence order;
transmitting a message on the communications medium from one of the
plurality of devices having communications control over the
communications medium; receiving the message from the
communications medium at each of the plurality of devices;
determining, at each of the plurality of devices, if the message
is: a unique code, or a combination of a sequence identifier and a
unique code; incrementing communications control to the next device
of the plurality of devices in the sequence order if the message is
the unique code; and transferring communications control to a
device identified in the sequence identifier if the message is a
combination of the sequence identifier and the unique code.
[0012] The present invention still further provides a
communications protocol for a communications bus wherein messages
are transmitted to a plurality of devices communicating by means of
a bus. Each message includes a unique code indicating the end of
the message and that same unique code triggers a transfer of
communications control to another device of the plurality of
devices.
BRIEF DESCRIPTION OF THE DRAWING
[0013] FIG. 1 is a block diagram of a communications system to
which the present invention is applicable.
[0014] FIG. 2 is a block diagram of a transmission of the unique
byte code of the present invention as implemented on a
communication system such as that shown in FIG. 1.
[0015] FIG. 3 is a block diagram of a bus message in accordance
with the present invention transferring communications control in a
non-sequential manner.
[0016] FIG. 4 is a block diagram of a bus message in accordance
with the present invention transferring data in a communications
system of FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
[0017] FIG. 1 shows a communications system 10 including a
communications medium 12 such as a communications bus 14. The bus
14 is preferably implemented in the form of a flat, four wire
ribbon cable using standard universal asynchronous
receiver/transmitter (UART) resources for eight bit communications
where two of the four wires provide power and common connections
and the other two of the four wires provide communications using
conventional RS-485 protocol. Although described in terms of a flat
ribbon connector and RS-485, a person of ordinary skill in the art
will recognize that the communications media 12 can be implemented
in a wide variety of manners including wireless communications,
spread spectrum RF communications, fiber optic media, coaxial
cable, and other communications connectors using a variety of
protocols appropriate for the media.
[0018] The communications media 12 communicably and operably
interconnects a plurality of electronic devices 20, 22, 24 and 28.
These devices 20, 22, 24, 28 are arranged into a sequence order
where each device 20, 22, 24, 28 has a sequence identifier
providing both an identity and a place in the sequence order. In
the case of the device 20, the identifier and place are the whole
number "1"; in the case of the device 22 the identifier and place
are the whole number "2"; in the case of the device 24 the
identifier and place are the whole number "3"; and so on through
the device 28 which has the identifier and last place in the
sequence order as indicated by the letter "N". By linking the place
in the sequence order with the device identifier, it is simple to
increment through the sequence order device by device. However, a
person of ordinary skill in the art will recognize that the
identifier and the place in the sequence order can be distinct and
linked in any conventional manner. Additionally, although the
present invention contemplates incrementing from device to device
by adding the value 1 when transferring bus control, a person of
ordinary skill in the art will recognize that more complicated
sequences will also achieve the same result.
[0019] The present invention combines master/slave and peer-to-peer
communications modes into the communications system 10 by providing
a communications message which works in a round robin format but
has an end of transmission handoff allowing sequential or
non-sequential changes in the order of handoff. This is
accomplished through the use a unique termination code such as a
unique code 18. The unique code 18 is preferably implemented as a
single byte with a specified value, but could be implemented as a
multi-byte code, or as a group of unique codes. For purposes of
this application, all such approaches are defined as the unique
code 18.
[0020] The unique code 18 is detected by low level hardware,
software or firmware to identify the end of a message transmitted
by one device, for example device 20, and cause an inherent change
in bus control to the next device 22 in the sequence order. In the
present invention, the sequence order is incremented by whole
number addition from device 1 to device 2 to device 3 and so on to
device N whereupon the sequence restarts at device 1. The plurality
of devices 20, 22, 24, 28 are preferably placed in a sequence order
at the time of system configuration; the sequence order, as noted,
running from device 1 through device N and then restarting at
device 1.
[0021] Device 1 would normally commence with communications control
over the communications media 12. If device 1 had no commands or
data to transmit or request, device 1 would transmit the unique
code 18 on the communications media 12 to all of the plurality of
devices 20, 22, 24, 28 in the form of a message 32. Each device 20,
22, 24, 28 receives the message 32 on the communications media 12
and determines if the message 32 is the unique code 18 by itself,
or a combination of a sequence identifier 42 and a unique code 18,
or a combination of a sequence identifier 42, data 46, and a unique
code 18. In the message 32, the unique code 18 always is the
message terminator and the type or nature of the message 32 is
determined, in part, by the length of the message 32 preceding the
unique code 18. If the message 32 is of a short length, the message
is solely the unique code 18, and each device 20, 22, 24, 28 will
recognize that communications control over the communications media
12 should be transferred to the next device 20, 22, 24, 28 in the
sequence order. If the devices 20, 22, 24, 28 are sequenced by
whole numbers, this transfer of control is accomplished by adding 1
to the sequence identifier 42 of the device currently controlling
bus communications.
[0022] If the message 32 is an intermediate length message, the
message includes a sequence identifier 42, and each device 20, 22,
24, 28 will recognize the sequence identifier 42 and substitute
that newly recognized sequence identifier 42 as and into
communications control of the communications media 12 thereby
moving elsewhere in the order of sequence order. The sequence
identifier 42 can be considered to identify the next device or node
to assume communications control.
[0023] If the message 32 is a longer length message, the message 32
includes data 46 providing a command, or reporting information, the
device 20, 22, 24, 28 will act upon that data 46 if it is relevant
to the particular device and then transfers control to the device
identified in the sequence identifier 42. Each message 32 will
transfer communications control to either the next device in the
sequence order or will transfer control to another device elsewhere
in the sequence order, depending upon whether the message 32 is
respectively the unique code 18, or a sequence identifier and
unique code 18.
[0024] FIG. 2 is a block diagram 30 of a message 32 on the
communications media 12. This message 32 is clearly the shortest of
the three message formats shown in FIGS. 2-4. The message 32 in
this case is the unique code 18. This unique code 18 can be
representative of a SYNC byte and is preferable, but not
necessarily, an eight bit code which can easily be interpreted by a
typical UART. It is also preferable that the unique code 18 be a
single byte to provide for fast or best communications. A person of
ordinary skill in the art will recognize that two or more
preselected codes could be used in place of a single unique code
and still achieve similar results.
[0025] FIG. 3 is a block diagram 40 of a message 32 on the bus
wherein the message includes a sequence identifier 42, the unique
code 18, and, potentially, data security information 44.
[0026] FIG. 4 is a block diagram 50 of a message 32 on the
communications media 12 wherein the message includes a sequence
identifier 42, data 46 such as a command, or a report providing
change of state or status information, the security data 44 and the
unique code 18 at the end of the message 48. This message 32 is
clearly the longest of the three message formats shown in FIGS.
2-4.
[0027] What has been described is a communications protocol which
combines master/slave and peer-to-peer communications modes in a
fast, flexible, efficient and simple manner. A person of ordinary
skill in the art will recognize that many changes and modifications
are possible through such a system. All such changes and
modifications are contemplated to fall within the spirit and scope
of the claimed invention.
* * * * *