Combination encoder-decoder integrated circuit device

• US 4,426,637 A
• Filed: 03/09/1981
• Issued: 01/17/1984
• Est. Priority Date: 02/26/1979
• Status: Expired due to Fees

• Current Assignee: Multi-Elmac Company
• Original Assignee: Multi-Elmac Company
• Inventors: Jacob, Keith D., Apple, William C.
• Primary Examiner(s): YUSKO, DONALD
• Application Number:
  US06/241,820
• Time in Patent Office: 1,044 Days
• Field of Search: 340/825.65, 340/825.69, 340/825.72
• US Class Current: 340/5.71
• CPC Class Codes: E05F 15/77 using wireless control
• CPC Class Codes: E05Y 2900/106 for garages
• CPC Class Codes: G08C 19/28 using pulse code

Abstract

A dual purpose integrated circuit device which can be utilized both as an encoder for providing digital signals according to a preselected code and as a decoder for comparing a received signal with an internally generated digitally coded signal. The device includes a plurality of input/output ports for making an electrical connection between external circuitry and functional portions of the device. The device includes a pulse generator for providing digital signals at its output according to a preselected code. The output of the generator is coupled to an output port for supplying the digital signals to a transmitter when used in the encoding mode, and provides the internally generated comparison code in the decoder mode. Improved circuitry is provided for selectively adjusting the level of security for a system utilizing the device in a transmitter-receiver system for activating a load such as a garage door opener, as well as for accommodating noise levels which may be encountered in authorized use.

Claims

1. A dual purpose integrated circuit device for both encoding and decoding digital electrical signals, said device comprising:

a plurality of input/output ports for making electrical connections between external circuitry and internal portions of the device, said device portions including;

generator means for providing a series of encoded digital words in which the bits thereof are formed in accordance with a preselected code;

means for connecting the output of said generator means to a first output port for transmitting said words to a receiver/encoder;

comparator means for comparing signals applied at its inputs and providing an output as a function thereof;

means for also coupling the output of said generator means to an input of said comparator means whereby to provide local code words;

means for coupling a first input port for receipt of received code words to another input of said comparator means;

means for coupling the output of said comparator means to a second output port for activating an external load depending upon the comparison between the received and local code words; and

whereby said device may be utilized either as an encoder or decoder by changing the external connections to the input/output ports of the device, with said same generator means being utilized to generate the transmitted digital words in the encoder mode and to generate the local code for comparison with the received code in the decoder mode.

2. The device of claim 1 wherein said generator means includes:

a counter for sequentially providing a plurality of count signals;

code select means coupled to a plurality of second input ports for receiving signals indicative of said preselected code; and

gating means connected to outputs of said counter and said code select means, operative to provide pulses of various widths defining the state of the bits in the digital words as a function of the preselected code.

3. The device of claim 1 wherein said comparator means includes means for sequentially comparing each bit of the local code word from the generator with each bit of the received code word.

4. The device of claim 2 which further includes tolerance means coupled to the output of said comparator means for determining the maximum amount of allowable deviation between the pulse widths of the bits of the received code word and the local code words generated by said generator means, with said tolerance means providing an output signal if the deviation exceeds a predetermined limit.

5. The device of claim 4 wherein said tolerance means includes adjustable means for adjusting the amount of allowable deviation before said output signal is provided.

6. The device of claim 4 wherein the output of said tolerance means is coupled to said counter to reset it in the event that an output signal is provided signifying detection of an untolerated mismatch between the received and local code pulses.

7. The device of claim 2 wherein said counter provides more count signals than code select inputs, and wherein said more signals are utilized to provide a synchronization time between successive digital words generated by the generation means.

8. The device of claim 7 wherein said comparator means further includes means for comparing the synchronization time between the received and local code words as well as the pulses thereof, with said comparator means producing a reset signal for resetting said counter upon detection of a mismatch, said counter being allowed to continue to count to a given number to provide a matched signal when said received and local codes completely coincide.

9. The device of claim 8 which further includes accumulator means for receipt of said matched signals from said counter, said accumulator means storing the number of matched signals regardless of their sequence and providing an output signal to said output port for activating the load upon receipt of a predetermined number of matched signals.

10. The device of claim 9 which further includes:

reset means coupled to said accumulator means for clearing the contents of said accumulator upon detection of a predetermined number of consecutive mismatched signals, wherein said device accommodates a limited number of mismatch signals due to interference.

11. The device of claim 10 which further includes an output latch coupled to the output of said accumulator means for activating said load, and wherein said reset means is operative to clear said latch means upon detection of a greater number of mismatched signals than needed to clear the accumulator before it originally sets said latch means.

12. In an automatic garage door operator system having a transmitter for transmitting a series of encoded digital words, and a receiver for decoding the words received from the transmitter and activating a garage door operator if the correct code words have been received, wherein the improvement comprises:

two identical integrated circuit devices, one device in the transmitter and the other device in the receiver;

each device having the same internal circuit means therein operative to generate a series of encoded digital words for transmission when the device is used in the transmitter and also operative for generating a series of local words for comparison with said encoded words for decoding same when the device is used in the receiver;

each of said devices including;

a plurality of input/output ports for making electrical connections between external circuitry and internal circuit portions of the device, said internal circuit portions of the device including;

generator means for providing a series of encoded digital words in which the bits thereof are formed in accordance with a preselected code;

means for connecting the output of said generator means to a first ouput for transmitting said words to the receiver;

comparator means for comparing signals applied at its inputs and providing an output as a function thereof;

means for also coupling the output of said generator means to an input of said comparator means whereby to provide local code words;

means for coupling a first input port for receipt of received code words to another input of said comparator means; and

means for coupling the output of said comparator means to a second output port for activating a garage door operator upon coincidence between the received and local code words.

13. A method of making a remote load activating system having a transmitter for transmitting an encoded digital word, and a receiver for decoding the word from the transmitter and activating a load if the transmitted word contains the correct code, said method comprising:

incorporating into the transmitter an integrated circuit device having a plurality of input/output ports for making electrical connections between external circuitry and internal portions of the device, said device portions including generator means for providing a series of encoded digital words in which the bits thereof are formed in accordance with a pre-selected code;

means for connecting the output of said generator means to a first output port for transmitting said words to the receiver;

comparator means for comparing signals supplied at its inputs and providing an output as a function thereof;

means for also coupling the output of said generator means to an input of said comparator means whereby to provide local code words;

means for coupling a first input port for receipt of received code words to another input of said comparator means;

means for coupling the ouput of said comparator means to a second output port for activating the load depending upon the comparison between the received and local code words;

connecting a series of code select switches to a plurality of second input ports coupled to said generator means for defining said preselected codes to be transmitted;

connecting the first output port to a transmission device for transmitting the encoded digital words to the receiver;

incorporating a second substantially identical integrated circuit device into the receiver;

connecting a second plurality of code select switches to said second input ports;

coupling the received encoded words from the transmitter to said first input port; and

connecting the second output port to the external load;

whereby substantially identical integrated circuit devices can be used in both the receiver and transmitter portions of the system.

14. The method of claim 13 wherein said second output port is connected to a garage door operator.