Automatic station identification where function modules automatically initialize

• US 5,204,669 A
• Filed: 08/30/1990
• Issued: 04/20/1993
• Est. Priority Date: 08/30/1990
• Status: Expired due to Term

• Current Assignee: Datacard Corp. (Entrust Corp.)
• Original Assignee: Datacard Corp. (Entrust Corp.)
• Inventors: Dorfe, Steven G., Jordan, James M.
• Primary Examiner(s): Yusko, Donald J.
• Assistant Examiner(s): Giust, John
• Application Number:
  US07/575,077
• Time in Patent Office: 964 Days
• Field of Search: 340/825.07, 340/825.08, 340/825.05, 340/825.52, 340/825.53, 370/85.8, 370/92, 364/200 MS File, 361/24
• US Class Current: 340/9.16
• CPC Class Codes: G06F 12/0676 the address being position dependent
• CPC Class Codes: G06F 15/177 Initialisation or configuration control processor initialisation G06F9/4405

Abstract

The present invention provides a method and apparatus for dynamically assigning addresses and determining the configuration of a plurality of programmable function modules connected to an electrical conductor, such as a serial bus. The programmable function modules are electrically interconnected by a control line in a point-to-point connection between one another. A programmable controller will first transmit an enabling signal on the control line and then will transmit predetermined addressing information on the serial bus. The first function module will then access the serial bus and retrieve the addressing information, assign itself a unique address as determined by the addressing information, modify the addressing information in a predetermined manner, return the modified addressing information to the serial bus, and enable the adjacent function module on the control line. Each function module connected to the serial bus will be assigned an address in a similar fashion. The programmable controller will receive the modified address information from the final function module and will thereby know the number of function modules, the connection sequence of the function modules, and the address of each function module.

Claims

1. A method for automatically assigning an address to an individual function module of a plurality of such function modules which are electrically interconnected to a controller by a common data bus for transmitting data to the function modules and a control line to which the modules are interconnected in point to point fashion, the method comprising the steps of:

a) beginning with a first function module F[N] where N equals 1, transmitting from the controller an enable control signal by way of the control line to the function module F[N] of the plurality of function modules F₈ [1]-F[TOTAL ] so as to enable the [first] function module F[N] and transmitting along the command data bus a predetermined number of pulses to the [first] function module F[N] of the plurality of function modules F[1]-F-[TOTAL];

b) the function module F[N] assigning itself a unique address as determined by the predetermined number of pulses received by the function module F[N] from the common data bus;

c) changing the number of pulses at the function module F[N] by a predetermined amount;

d) if electrically connected to an adjacent function module F[N+1] by a loopback signal circuit separate and distinct from the common data bus and the control line, transmitting an enable control signal by wall of the control line from the function module F[N] to the adjacent function module F[N+1] of the plurality of function modules by way of the control line so as to enable the adjacent function module F[N+1] and then transmitting from the function module F[N] the changed number of pulses along the common data bus to the adjacent function module F[N+1] connected to the common data bus;

e) repeating steps b)-d), increasing N by one, until the function modules have been assigned addresses; and

f) if not electrically connected to an adjacent function module N[N+1] by a loop back signal circuit, transmitting an enable control signal to the controller by a second control line and transmitting along the common data bus the changed number of pulses determinable of the final module'"'"'s address to the controller.

2. The method of claim 1 wherein step e) further comprises checking whether the adjacent function module F[N+1] is electrically connected to yet another adjacent function module F[N+2] for determining if all the function modules have been addressed.

3. The method according to claim 2 wherein checking whether the adjacent function module F[N+1] is electrically connected to yet another adjacent function module F[N+2] comprises checking for the presence of the electrical conductor connected to a communication output port of the adjacent function module F[N+1].

4. The method according to claim 1 wherein the step of transmitting and receiving pulses by the function modules and the controller comprises transmitting and receiving clock pulses.

5. The method according to claim 1 wherein the step of transmitting a predetermined number of pulses to the function module F[N] comprises transmitting one pulse and the step of changing the number of pulses by a predetermined amount comprises incrementing the number of pulses by one pulse.

6. The method according to claim 1 wherein the step of assigning a unique address to the function module F[N] comprises assigning the number of pulses received by the function module F[N] as its unique address.

7. The method according to claim 1 wherein the step of transmitting the fiber of pulses indicative of the final function module'"'"'s address comprises transmitting the number of pulses received by the final function module changed by the predetermined amount.

8. The method of claim 1 further comprising the step of polling the function modules for determining the function of each function module;

9. An automatic station identification system comprising:

a) a common electrical conductor means for electrically conducting address information;

b) a programmable controller adapted to access the common electrical conductor means for transmitting and receiving address information on the common electrical conductor means;

c) a plurality of programmable function modules, each function module being electrically connected to the common electrical conductor means for transmitting and receiving address information, the function modules being further electrically interconnected to the programmable controller in point to point fashion by control line means, separate from the common electrical conductor means, for transmitting control signals;

each function module programmed to receive address information for the common electrical conductor means upon being enabled by an enable signal transmitted on the control line means, assign itself a unique address as determined by the address information, modify the address information in a predetermined manner, either enable an adjacent function module by transmitting an enable signal on the control line means if electrically connected to an adjacent function module by a loopback signal circuit separate and listing from the common data bus and the control line means or enable the programmable controller by transmitting an enable signal on a second control line means if not electrically connected to an adjacent function module by a loopback signal circuit, and transmit the modified address information on the common electrical conductor means;

d) programmable controller being programmed to enable a first function module by transmitting an enable signal on the control line means and to transmit predetermined address information on the common electrical conductor means and being further programmed to receive the modified address information as transmitted by a final function module of the plurality of function modules.

10. The system according to claim 9 wherein the predetermined address information comprises a predetermined number of clock pulses and wherein the predetermined manner in which the clock pulses are modified comprises changing the number of clock pulses by a predetermined amount.

11. The system according to claim 10 wherein the predetermined number of pulses sent by the programmable controller is one pulse and the predetermined amount the programmable function modules change the received number of pulses is an increment of one pulse.

12. The system according to claim 9 wherein the electrical conductor means is a serial bus.

13. The system according to claim 12 wherein the serial bus further includes two additional lines for additional control signals wherein a first additional line is electrically interconnected from the programmable controller to the first programmable function module and thereafter in a daisy-chain fashion to and from each programmable function module in the system and wherein a second additional line is electrically interconnected between the last programmable function module and the programmable controller.

14. An automatic station identification system comprising:

a) a common data bus for electrically conducting information;

b) control lines for electrically conducting control signals;

c) a programmable controller adapted to access the common data bus and the control lines for transmitting and receiving address information on the serial bus and control signals on the control lines;

d) a plurality of programmable function modules including a first programmable function module electrically interconnected to the programmable controller by a first control line, each programmable function module thereafter electrically interconnected in a point to point fashion with the first control line, a last programmable function module electrically interconnected to the programmable controller with a second control line, each programmable function module adapted to access the common data bus for transmitting and receiving information;

e) the programmable controller programmed to transmit predetermined address information on the common data bus, to transmit an enabling signal on the first control line to the first programmable function module, and to receive final address identification information from the last programmable function module on the second control line; and

f) each programmable function module of the plurality of programmable function modules programmed to receive the enabling signal from the first control line, access the common data bus to receive the address information, assign itself a unique address as determined by the address information, modify the address information in a predetermined manner, return the modified address information to the common data bus, and transmit the enabling signal to an adjacent programmable function module, if electrically connected to an adjacent function module by a loopback signal circuit separate and distinct from the common data bus and the first control line, or to the programmable controller if not electrically connected to an adjacent function module by the loopback signal circuit.