Abstract 57 A method for dynamically assigning addresses to new modules as they are coupled to a communication system (100) with a synchronous data link control (SDLC) bus is described. These modules communicate with a display unit via the SDLC bus. The SDLC bus is controlled by a primary station (102) in the display unit, with all modules acting as secondary stations (104, 106, 108). The primary station (102) periodically broadcasts a time-tag to all modules at a thirty-two hertz rate. At power up, each module obtains a number, modulo 16, derived from the lower four bits of its unique twenty-four bit serial number. The module uses this number as a count of the number of time-tags which must occur before the module responds to the primary with an address request. If there are no collisions with other modules, the primary sends the module a packet which assigns the module the next available address. In the event of a collision (i.e., two or more modules request an address at the same time), the primary SDLC controller detects a CRC error and ignores the SDLC frame. The modules will each time-out and obtain a new number, modulo 16, derived from the next significant four bits of the module serial number. This process continues until the module obtains an address. (Fig. 1) .
A method of synchronizing to a multipoint communication system wherein a primary station and a plurality of secondary stations are coupled together over a serial data bus comprising the step of: dynamically assigning an address to a new secondary station upon coupling to said system.
Claim 2
Independent Claim
45 words
A method of synchronizing to a multipoint communication system wherein a primary station and a plurality of secondary stations are coupled together over a serial data bus comprising the step of: dynamically assigning an address to a new secondary station upon coupling to said system.
Claim 3
Dependent Claim
83 words
The method of Claim 1 wherein said method further comprises: periodically broadcasting time-tags to all of said secondary stations simultaneously during an address initialization phase at the beginning of each poll interval; automatically determining a time-tag count number for each of said new secondary stations upon coupling to said system; waiting said count number poll intervals before requesting an address assignment from said primary station during said address initialization phase of said chosen poll interval; and assigning an address to said secondary station.
Claim 4
Dependent Claim
34 words
The method of Claim 1 wherein said method further comprises the steps of: automatically determining a new time-tag count number when two or more secondary stations request address assignment during the same poll interval.
Claim 5
Dependent Claim
86 words
The method of Claim 3 wherein said method further comprises the steps of: preassigning to each secondary station a unique multibit serial number; choosing a first predetermined subset of said multibit serial number as the basis of said first count number; and choosing a second predetermined subset of said multibit serial number as the basis for a second count number in the event of a simultaneous address request by two or more secondary stations, and so on until each new secondary station receives an address assignment.
Claim 6
Dependent Claim
17 words
The method of Claim 4 wherein said subset of said predetermined multibit number comprises said count number.
Claim 7
Dependent Claim
52 words
The method of Claim 3 wherein said method further comprises the steps of: preassigning to each secondary station a unique multibit serial number; and using said serial number as the seed of a random number generator to generate a series of random numbers for use as the basis for said count numbers.
Claim 8
Dependent Claim
26 words
The method of Claim 2 wherein each of said new secondary station assumes a predetermined address until a unique address is assigned by said primary station.
Claim 9
Dependent Claim
39 words
Multipoint communication system with a primary station and a plurality of secondary stations being coupled together over a serial data bus, characterized by means for dynamically assigning an address to a new secondary station upon coupling to said system.
Claim 10
Dependent Claim
39 words
Multipoint communication system with a primary station and a plurality of secondary stations being coupled together over a serial data bus, characterized by means for dynamically assigning an address to a new secondary station upon coupling to said system.
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