GB2297412A - Vehicle control system with trainable transceiver - Google Patents

Description

1 2297412 VEHICLE CONTROL SYSTEM WITIA TRAINABLE TRANSCEIVER The invention

relates to a control system for a vehicle, and more particularly, to a sys tciii for controlling vehicle options responsive to a kcyless entry remote control signal,uid for learning and selectively transmitting control signals for actuating a garage door opening mechanism.

This application is divided out of GB Patent Application No. 9504846.8 in the name of Prince Corporation.

Keyless entry systems including a remote keyless entry (R.KE) transmitter which transmits a radio frequency (RF) control signal and a vehicle receiver which detects the RF control signal from tile RKE transmitter to control vehicle door locks responsive thereto are well known. RF remote controls for actuating garage door inechanisnis frorn a vehicle are also well known. These systems typically include separate circtiitrv since the garage door openinu remote control is typically a transmitter which is mounted within a housing that the car owner may store in the vehicle, but is not Intcgrated into the vehicle electrical systelli viiereas the keyless entry receiver includes an RF receiver -dilch is integrated into (fie vehicle electrical system. The separate circuitry is also neccssary because the garage 1 4- door Opening nieclianisni and the keyless entry system operate at different frequencies, have different signaling formats, and use different security codes.

The present invention provides a transceiver having an improved integrated trainable transmitter and vehicle operition control systern for a vehicle. The transceiver includes an Input circuit receiving radio frequency signals from a garage door opener reniote control In a training niode and from a separate transmitter in a transmitter detection niode. The transceiver 31SO includes ail Output circuit generating radio frequency signals for lCtL:3',IIILI a device controlled by the remote control. A controller detects signals frorn the Input cIrCUIt and controls the output circuit while an interface circuit couples the control!er to the vehicle's electrical systeni for controlling vehicle options in response to received signals.

-,\ccol-(illlii to a First aspect of the Invention. the Input circuit includes an amplitude -1 co 1 1 1 Iltrol is used to adjust (lie sensitivity (i.e., receptioil rnge) Of the transceiver. According to another aspect of the Invention, the transceiver disconnects the output circuit froni an antenna associated ilierc,.vitli when (lie controller is in a remote control training niode or a reception niode. According to anotlicr aspect of the invention, the controller is responsive to a first input signal to operate In a receive niode, to a second user initiated control signal to operate in a tratisinit niode, and to a third signal which Is automatically generated for Initiating reception of a signal frorn said reniote transmitter.

2 The systeni according to the invention integrates a trainable rcillote control for actuating devices renlote from the veiiicic and a receiver to control a vehicle option responsive to a signal froill a rernote transmitter. The input circuit aniplifier variable gain adjusts the circuit such that it llas a significantly less sensitivity in remote control training C; mode tlian In a transmitter signal reception niode. The system also has a significantly iniproved signal to noise ratio for received signals by eliminating noise which may otherivise be conveyed from the output circuit to the input circuit of the transceiver. The system also provides niore versatile operation, allowing user control as well as automatic power control. Iliereby effectini, power savings.

is According to the invention there is provided a trainable transceiver system for a vehicle, comprising: an antenna; a transceiver operable in one of a plurality of modes including a training mode and a signal transmission mode, said transceiver including an input circuit and an output circuit, said input circuit selectively receiving RF signals transmitted from an RF remote control transmitter during the training mode, and said output circuit selectively generating RF signals during the signal transmission mode for actuating a controlled device, wherein the RF signals transmitted during the signal transmission mode have learned characteristics of the RF signal received during the training mode; a switch coupled between said output circuit and said antenna, said switch having a control input at which a control signal is input which controls the state of said switch; and a controller coupled to said input circuit, to said output circuit, and to said switch, said controller controlling said switch to disconnect said output circuit from said antenna when said transceiver is operating in the training mode. Other aspects of the invention are set out in the 3 following clauses:

1 A trainable transceiver system for a vehicle. comprising a transceiver operable ill one of a plurality of operating modes including a training mode, a signal transmission mode, and a transmitter signal detection mode, said transceiver including in input circuit for receiving radio frequency signals transmitted from -a remote control transmitter, said input circuit including a variable gain amplifier having an amplitude control input; and a control circuit coupled to said amplitude control input of said input circuit for selectively varying the gain of said variable gain amplifier to decrease the sensitivity of said input circuit when said transceiver is operating in (lie training mode for receiving signals froni said reniote control transmitter.

2. The transceiver system as defined in 1,,,,iicre[ii sald transceiver further includes an output circuit coupled to said control circuit for selectively generating radio frequency signals under the control of said control circuit.

Z:1 3. The transceiver system as defined in 1, where:n said variable gain amplifier fully attenuates a signal Input thereto when said transceiver is not operating in the transmitter signal detection mode or in the training niode.

4- The transceiver system as defined in 2, further including an antenna and a s,,.itch for selectively connecting said output circuit to said antenna. said control circuit coupled to said s-witch to control said sivitch.

5. The transceiver system as defined in 2, further including a user actuated selector -and an interrupt tinier for controlling said transceiver to change operating modes.

6. A trainable transceiver system for a vehicle having an electrical system, comprising a transceiver operable in one of a plurality of operating modes including a training mode, a signal transmission mode, and a transmitter signal detection mode. said transceiver including an input circuit for receiving radio frequency signals transmitted from a separate reniote control for a garage door opening device and the radio frequency signal transmitted froni a remote transmitter for controlling vehicle option operation, said input circuit including an amplitude controller having an amplitude control input, and an output circuit, 4 responsive to output control signals, for selectively generating radio frequency control signals for actuating the garage door opening device without (lie separate remote control; an interface circuit coupled to the electrical systein of (lie vehicle; and a controller coupled to said input circuit, said output circuit, and to said interface circuit, wherein when said transceiver is in a training mode, said controller receives signals from said input circuit and stores information about the received signals. when said transceiver is in the signal transmission mode. said controller selectively provides output control signals to said output circuit, when said transceiver is in the transmitter signal detection mode, said controller selectively provides option control signals to said interface circuit to control operation of the vehicle electrical system in response to a detected signal from the remote transmitter, and wherein said controller provides amplitude control signals to said amplitude control input to selecti,,eiy adjust the sensitivity ofsald transceiver according to tile operating niode of the transceiver.

7. The transceiver system as defined in includes a variable gain amplifier.

6..%,herein said amplitude controller 8. Tile transceiver systern as defined in 7. wherein said variable gain amplifier has a gain control input coupled to said controller, and wherein said amplitude control signal is input to said gain control input such that said input circuit has a lower sensitivity "lien said transceiver is in the training niode to learn the remote control signal from the remote control and a greater sensitivity when the transceiver is receiving a signal from the remote transmitter while in the transmitter signal detection mode.

9. The transceiver system as defined in 8, wherein said variable gain ampliflier fully attenuates a signal input (hereto when said transceiver is not in the transmitter signal detection i-node or in tile training mode.

10. The transceiver system as deFined in includes a variable attenuator.

6. wherein said amplitude controller 11. Tile transceiver system as defined in 10. wherein said variable attenuator is coupled to said controller, and wherein said amplitude control signal is input to said variable attenuator such that said input circuit has a lower gain when the transceiver is in the training i-node and a higher gain when the transceiver is in the transmitter signal detection mode.

12. The transceiver system as defined in 11, wherein said variable attenuator fully attenuates a signal input thereto when said transceiver is not in a transmitter signal detection mode or in a training mode.

13. The transceiver system as defined in 6, including an antenna and a switch for selectively connecting said output circuit to said antenna, said controller coupled to said switch to control said switch.

14. The transceiver system as defined in fi, further including a user actuated selector and an interrupt timer for controlling said transmitter to change operating modes.

15. A transceiver system for a vehicle, comprising an antenna; a transceiver having an input circuit and an output circuit. said input circuit having an input and an output, said input circuit selectively receiving RF signals at said input and responsive thereto for outputting data signals at said output, and said output circuit selectively generating RF signals for actuating a controlled device. said output circuit having an output at which RI - a switch coupled between said output of said output circuit and said signals are output. antenna, said switch havino a control input at which a control signal is input which 0 controls a state of said switch; and a controller coupled to said input circuit, said output circuit and said switch, said controller controlling said switch to disconnect said output of said output circuit from said antenna when said transceiver is operating in a receive mode.

16. The trainable transceiver system as defined in 15, wherein said switch is coupled to said input of said input circuit and to said output of said output circuit, said switch responsive to said controller for connecting said antenna to said input of said input circuit when said transceiver is receiving a signal.

17. The trainable transceiver system as def ined in claim 16, wherein said input circuit includes a mixer having a first input and said output circuit includes a variable frequency generator having an output, and wherein said output of said variable frequency generator and said f irst input of said mixer are coupled to respective terminals of said switch.

6 A trainable transceiver sYstem for a.,elilcie hiving, ih electrical system, comprising 18. a transceiver Including all input circult lor receiving radio frequency. signals and an output circuit for selectively generating radio frequency signals. a connector coupled to the vehicle electrical system; a tiser interface including actuators for inputting first and second control signals. ill interrupt signal generator for generating a third control signal; and a controller coupled to said Input circuit, said output circuit, said connector, said user interface. and said interrupt signal generator, wherein said controller controls said transceiver to operate in a transmit illodc responsive to said First signal from said user interface, said controller controls the transceiver to operate in a training mode responsive to said second control signal from slid user Interface. and said controller controls the traiiscei,,,. er to enter a transmitter signal detection mode responsive to said third control signal.

19. 'rile transceiver system as defined in 18 x.,.liercin said Interrupt signal generator Includes an interrupt tlilier which periodically generates an Interrupt signal to said Interrupt signal generator responds by generating said third control signal.

20. The transceiver system as defined in -,q wherein said controller initializes timer upon entering a sleep mode whereby, said Interrupt tinier sat 1 1 interrupts the sleep rilode aii(oviiaticilly at [lie end of a sleep interval hy generating said izitcrrupt signal.

21. The transceiver system as defined Ill 2 3 at least one switch.

22. The transceiver system as defined 111 21 ,'licrein said user interface includes wherein said First control signal is generated when said sx\,.ltcii Is lield for a first predeterini tied tinie period.

23. The transceiver system as defined in 22 whereln said second control signal Is gencrated \,.licii said svvitch is lield Ibr a sc(:oill predeternilned tline period.

24. The ti-ziiiscei,,,er ss,-stciii as (ici-itied ill,xliereiti said controller controls said 12 -' transceiver to enter a transmitter si-grial detection illode f-ollo.\,,n2 said training mode or sat([ tratismit mode.

25. A trainable transceiver system for a vehicle comprising a transceiver including an input circuit for receiving radio frequency signals transmitted from a remote control transmitter and a radio frequency signal transmitted froni a second separate transmitter, said input circuit including a variable gain amplifier having an amplitude control input, and an output circuit for selectively generating RF. st-nals transmitted to actuate a remotely controlled device without the remote control transmitter, an antenna, a switch for selectively connecting said antenna to said output circuit of said transceiver; and a control circuit coupled to said amplitude control input and to said switch for varying (lie gain of said variable gain amplifier to decrease the sensitivity of said input circuit of said transceiver when in a training niode, and for receiving signals from said remote control and selectively disconnecting said output circuit froni said antenna when said transceiver is in a reception state.

26. A trainable transceiver system for a vehicle. comprising a transceiver including an input. circuit for receiving radio frequency signals transmitted from a remote control transmitter and a radio frequency signal transmitted from a second transmitter, said input circuit including a variable gain aniplificr having an amplitude control input; an interrupt circuit having a control Input, for selectively generating an interrupt signal; and a control circuit coupled to said amplitude control itiptit and said interrupt circuit, said control circuit selectively varying the gain of said variable gain amplifier to decrease tile sciisiti,ity of sald Input. eirciiit of said transceiver when In a training mode, and said control clicult selectively placing said transceiver in a power conservative sleep state during which said transceiver is brought out of the sleep state in response to said interrupt signal.

27. The trainable transeeiver system as del-ined 111 26 f01. 111.111izili Inpulting, I-ii"st and second control si(-,iials.

The trainable transeeiver systeni as defined in- 2 7 wherein said interrupt signal generator includes a tinier for atitotilattc,-tllv generating said interrupt signal a predetermined tinie after said control circult wes Into the sleep state.

further including actuators 8 29. A trainable transceiver system for a veliicle comprising a transceiver including an input circuit fior receiving radio frequency signals transillitted froni a reniote control transmitter and a radio frequency signal transmitted from a second separate transmitter, and an output circuit for generating RF signals wlilch are selectively transmitted to actuate a retilotely controlled device without the remote control transmitter. an antenna; a switch for selectively connecting said antenna to said output circuit of said transceiver; an interrupt circuit for selectively generating an interrupt signal; and a control circuit coupled to said si.,.iteli and to said interrupt circuit, said control circuit controlling said switcli to connect said antenna to said output circuit during a receive state of said transceiver, and said control circuit selectively placing the transceiver in a low power consumption niode to conserve power during.vliicli said transceiver returns to a full operating niode in response to an interrupt signal.

30. A trainable transceiver system for a vehicle, comprising a transceiver operable in one of a plurality of operating modes including a training mode, a signal transmission mode, and a transmitter signal detection mode, said transceiver including an input circuit for receiving radio frequency signals transmitted from an RF remote control transmitter for controlling a garage door opening device, and from a remo6e keyless entry transmitter for actuating vehicle door locks; and a control circuit coupled to said input circuit for learning the RF frequency and code of signals received from said RF remote control transmitter when said transceiver is operating in the training mode and for receiving signals from said keyless entry transmitter when said transceiver is in said signal detection mode.

9 These and other aspects, features and advantages of the present invention will beconic apparent upon reading the following description thereof, together with referctice to the accompanying, draxyings in whicit:

Fig. 1 is a pictorial vicw of a vehicle including a transceiver according to the present invention.

Fig. 2 is a perspective view of a receiver housing according to the invention; Fig. -3 is an opposite perspective view of a transceiver housing according to Fig. 2; FiL,. 4 is a circuit schematic of the transceiver according to the invention shown in block. diagram forin; and Fig. 5 is a now diagrain oF the program for controlling the operation of the trinsceiver accordIng to FW. 4.

Initlail\ to Fi,,s. 1-3. a vehicle 8 is illustrated including a transceiver 12 accordinu, to the Invention. The invention is Integrated into a sniall. oenerally square module liousiii-, 10. Housinu 10 encloses a transceiver 12 (Fig. 4),.Iiicii selectively transmits coded radio frequency (RF) enerov, as indicated by arrow "'F" to a de,,,-tce controlled by an RF control sional, such as a garage door opening mechanism 14 shown in block form in Figs. 1 and 4. The conventional garage door opening illechanisill 14 includes a receiver and control circuit (not shown) which responds to [fie control signal "T" for opening and closing, a garage door. Transceiver 12 includes a programmable microcontroller 16 (Fig 4),%.llicii controls an RF output circuit 18 to generate signal "T." Signal -1- has a Cl-equency and code learned frorn signal "B" transmitted by existing reniote control transmitter 20 and identified by transceiver 12 in a training mode. The transcevver, after learning the carrier frequency, format and code of signal "B," can transmit remotc control signal 'I- to activate tile garage door opening control mechanism 14 without further need for tile remote control transmitter 20. Transmitter 20 is typically provided with garage door opening mechanism 14 and generates control signal "B" for remotely actuating the garage door opening mechanism.

Transceiver 12 also responds to control signals 'W' from keyless entry renlote control 22. An R.F. input circuit 19 demodulates signal 'W' and outputs control signals to the vehicle electrical system responsive thereto. For example, the keyiess entry remote control may control vehicle door locks. a trunk lock and a gas door cover. Responsive to signal "K," the rnicrocontroller outputs a control signal to serial bus 24 which controls the vehicle accessories or options according to the input control code.

flousing 10 Is small, such that it may be integrated into a variety of accessories in the vehicle, such as In a rearview ilitri-or, an overhead console, a map light, a visor, the instrument panel. or any. other suitable location in the vehicle. The transmitter includes three switches 26, 27 and 28 in a front panel face 30. Each switch is associated with a respective channel, and each channel stores a respective RF. control signal in a training mode for remotely actuating one device. For example, the three channels may have three signals associated with three respective garage door opening mechanisms. Alternatively, two of the channels can have signals for two, respective. garage door openers, and the third channel can have a signal for controlling an interior house light, exterior house lights, or the like.

Each of switches 26-28 is used both to train and to actuate its respective channel.

For example, if one of these switches is field for less than a predetermined period (e.g., less than 5 seconds), transceiver 12 will transmit the signal stored for that channel. If the switch is field for longer than the predetermined tinie period, microcontroller 16 will enter the training mode for the control channel associated with that field switch. An LED 32 is provided on front panel face 30 to inform the operator of the operational mode. For example. the LED is illuminated continuously while a signal is being transmitted, flashes in the training mode, and flashes at a rate five times faster than the training mode rate when the training mode is Finished.

It is envisioned that a fourth switch (not shown) can be provided on housing 10 which is actuated to initialize a training mode for transceiver 12 whereby the trainable transceiver learns transmitter signal "K" from a new transmitter which can be used after training to control vehicle options.

11 The back panel 40 includes a connector 42 for connection to the vehicle electrical system serial bus 24. This connector 42 mates with a complementary connector 43 (Fig.

4), which is coupled to a vehicle serial bus 24, when the housing is installed in tile vehicle. The serial bus may, for example, be a multiplexing bus having two, four, ten or more conductors and connected to a main microcontroller (not shown) for the vehicle electrical system. The microcontroller 16 thus communicates with vehicle accessories through the multiplex bus on the vehicle. It will be appreciated by those skilled in the art that microcontroller 16 may be connected to the vehicle electrical system microcontroller or it may be connected directly to the vehicle options being controlled, as will be required by tile vehicle elcctrical system.

Although the overall preferred mounting environment is described with respect to tile generally square housing 10. transceiver Q according to the invention may be used in other environments. For example. the iniprovcd transmitter of the immediate invention may be used as an integral part of a rearview mirror or as an integral part of a sun visor.

an overhead console. or the like.

Having briefly described the overall preferred mounting environment and operation of transmitter 12, and its relationship to a vehicle. a detailed description of the preferred embodiment is now presented in connection first with the circuit diagram of Fig. 4, and subsequently with reference to the flow diagram of Fig. 5.

Operation of transceiver 12 is controlled by inicrocontroller 16. Transceiver 12 includes a power supply 45, a user input 46 for controlling the microcontroller 16, an interrupt circuit 47 generating an external interrupt and responsive to a reset signal for restarting a tinier in the interrupt circuit, a user output 48 providing information to tile operator, and a connector 42 connected to serial bus 44. which in turn is connected to tile vehicle electrical system. An RF signal input circuit 19 and the RF signal output circuit 18 are connected to microcontroller 16 for receiving and transmitting RF signals.

The user input 46 (Fig. 4) and tile user output 48 provide an operator interface.

The user input includes switches 26-28 (Fig. 2) which provide operator actuated control of the training and transmitting mode for the trainable transceiver 12 (Fig. 4) which controls device 14 without reniote control 20. The user output 48 includes visual indicator 32 or a vacuum fluorescent display. The visual indicator 32 indicates the operating mode of the trainable transceiver by constant illumination or various flashing rates. If the system is used with a compass or a thermometer, the user output 48 may include an alpha-nunieric 12 display. The alpha-riumeric display would provide additional information such as vehicle heading and outside temperature information. Microcontroller 16 is also connected to power supply 45, which provides a regulated supply voltage and a standby enable signal.

The RF signal output circuit 18 includes a phase locked loop circuit 51 connected to the frequency output 57 of microcontroller 16 through a parallel data bus 52. The phase locked loop circuit 51 is impleniented using any suitable integrated circuit such as the Motorola MC145106, driven by an 8 MFIz oscillator. The phase locked loop 51 Is responsive to the frequency selection signals at output 57 of microcontroller 16 to generate a DC signal at output 59.

The output signal at output 59 of the phase locked loop circuit 51 is filtered in lowpass filter 54. The output ol'the lowpass filtcr is connected to a switch 56. S-witch 56 is connected to output 50 of microcontroller 16. A sample-and-hold circuit 58 is connected to switch 56 and holds the signal output from the low-pass filter during a frequency selection interval. The sample-and-hold circuit may be iniplemented using any suitable means such as an IC No. 4066 switch, a capacitor and an amplifier.

The output of sample-and-hold circuit 58 is the DC control signal for a voltage controlled oscillator (VCO) 60. The frequency of the oscillating signal output by VCO 60 is set by the DC signal output from sample-and-hold circuit 58. The VCO includes a switch (not shown), which may be implemented using a transistor. and which is switched on and off under the control of a data signal at input 64. Input 64 is connected to output 63 of microcontroller 16 by conductor 61. The VCO enable signal at output 63 switches VCO 60 on and off according to data signals stored in microcontroller 16, which data is learned in the garage door opener remote control training mode.

The signal output by VCO 60 is filtered in lowpass filter 65. The amplitude of the signal output by the low-pass filter is controlled by an attenuator 67. Attenuator 67 is preferably implemented by a plurality of series circuits. each of which comprises a respective transistor (not shown) and a resistor (not shown) connected in series between the Output of VCO 60 and ground. The attenuator is connected to output 66 of rnicrocontroller 16 through a data bus 73. Data bus 73 has a respective conductor for each series circuit in attenuator 67. The transistors are each connected to a respective conductor of bus 73 such that they are selectively turned on and off under the control of microcontroller 16. The output signal of the attenuator 67 is input to a buffer 62. Buffer 62 may be implemented by any suitable buffer circuit, such as a unity gain amplifier or an 13 emitter- follower transistor configuration. The output of buffer 62 is connected to one terminal 68 of a switch 70. an input 69 of pliase locked loop 5 1, and to one Input 71 of a mixer 72. Switch 56 is controlled such that the signal output from Filter 54 is mo

file litari ly 5 input to the sample-and-hold circuit 58 at the beginning of a frequency select interval. When a new frequency is output, or if the sample-and-hold circuit requires refreshing, the switch is closed and the signal output from lowpass filter 54 is sampled again. This control of switch 56 prevents oscillation or other variations of the control signal input to VCO 60. Accordingly, the VCO 60 will generate a stable output signal during the frequency interval. The output of but'I"Cr 62 is an oscillating signal liaing a carrier frequency set by the signal on parallel data bus 52.

The transcelver 12 includes.in antenna 74 which is connected to contact 76 of switch 70. Switch 70 is coupled to output 75 of microcontroller 16. The switch may be implemented by any suitable switch such as a relay driven by the output signal of nilcrocontroller 16. Switch 70 is controlled bv sionals from microcontroller 16 such that c the contact 76 connects anterula 74 to terminal 78 in the receive state. In the transmit state, the contact connects antenna 74 to terminal 68. The switch is thus used to selectively isolate the antenna 74 from the output of the buffer 62 in the receive state, thereby enhancing circuit performance by reducing noise in the received signal which would otherwise result from the coupling of the input and output circuits.

Although transceiver 12 preferably includes a single antenna 1 7 4. those skilled in the art will recognize that two antennae (not shown) could be used.. one for the RT signal input circuit and one for the RF signal output circuit. If such separate antennae are provided, a respective switch (not shown) would be connected between each antenna and its associated circuit. The switches would then be controlled such that only one is closed at any i g ven time.

The RF signal input circuit 19 includes mixer 72, which has a first input 77 connected to contact 76 and a second input 71 connected to the output of buffer 62. The mixer combines the signal detected by antenna 74 with the oscillating signal output by buffer 62. The output signal of the iiiixer 72 is filtered by bandpass Filter 84. The bandpass filter 84 removes noise frorn the output of the rnixer 72. The Filtered signal is input to an intermediate frequency aniplifiter 88 having a gain control input 90, Gain control Input 90 is connected to output 92 of microcontroller 16. The IF amplifier 88 may 14 be implemented using any suitable means such as an aniplifier with a variable feedback impedance. The gain control input signal varies the amplifier gain between three levels. The amplifier is controlled to have a high gain level for receiving signals from transmitter 22 and a low gain when training to a signal B from remote control 20. Tile IF amplifler 88 has a low gain when transceiver 12 is in a training niode to reduce the sensitivity of the receiver, and thereby lower the range, such that only those signals transmitted from a source.,,.itliin a radius of approximately 1 to 10 feet are detected. This insures that the transceiver learns a signal from the desired remote control and does not detect signals from any nearby RF transmitters. In a transmitter detection niode, for inputting a signal from transmitter 22. the gain of aniplifier 88 is controlled to provide the transceiver with a significantly greater sensitivity. This allows transceiver 12 to detect a signal frorn a keyless entry transmitter 22 while the user is still several car lengths away froni vehicle 8 (Fig. I). When transceiver 12 (Fig. 4) is not in the training niode or the transmitter detection niode. the gain of the IF amplifier can be controlled to be at substantially OdB, to prevent noise from the receive circuit being input to controller 16.

The output of the IF amplifier 88 is input to an AM demodulator 93. The output of demodulator 93) is input to a data amplifier 94. The data amplifier includes a comparator which compares the signal output from the demodulator 93 to a fixed reference signal. If the output of demodulator 93 exceeds the reference signal, the comparator outputs a high logic level signal. Otherwise, the comparator outputs a low logic level signal. The output of the data amplifier 94 is connected'to input 99 of microcontroller 16.

The interrupt circuit, or sleep tinier, 47 is connected to input 98 and output 97 of microcontroller 16. The sleep timer is connected to input 98 of microcontroller 16. Sleep tinier 70 is implemented using any suitable low power consumption timer which outputs a timer interrupt signal a predetermined time period after it is reset by the reset signal from rnicrocontroller 16.

The circuit represented by Fig. 4 is a self-contained trainable transmitter for the environment illustrated in Fig. 1. The reset/power-up operation will now be described with reference to Fig. 5 and the circuit of Fig. 4. Microcontroller 16 initiates transmit/receive state control following an external interrupt generated by the sleep timer 47, upon power-up of rnicrocontroller 16. or when one of switches 26-28 is actuated. Microcontrolicr 16 (Fig. 4) first determines whether one of switches 26-28 (Fig. 2) is actuated, as indicated in block 100 (Fig. 5). If one of switches 26-28 was actuated, microcontroller 16 determines that the transrnit/receive operation to be performed pertains to the garage door opener remote control operation, as indicated in block 102. If one of.switches 26-28 is riot actuated, microcontrolicr 16 determines that the transmitter was powered up or that interrupt tirner 47 generated an interrupt signal, as. indicated in block 5 104.

If microcontroller 16 determines that one of switches 26-28 is actuated, the microcontroller transmits a signal as indicated in block 106. To transmit an signal, microcontroller 16 outputs a signal at output 75 which controls switch contact 76 to connect antenna 74 to buffer 62 through terminal 68. Microcontroller 16 then outputs a control signal at output 57 which controls the phase locked loop 50 to output a DC signal which drives the WO 60 to have a desired carrier frequency which was previously stored ill association with the one of the s,itelies 26-28 xvinch is actuated. 'Nficrocontroller 16 also outputs a data signal at output 63),.litch controls voltage controlled oscillator 60 to turn on and off according to the data signals stored for that actuated switch.

As indicated in decision block 108, rnicrocontroller 16 continues to monitor the actuated switch. while the transceiver is transmitting the signal. If microcontroller 16 determines that the switch is actuated for longer than a predetermined minimum time period (e.g., 5 seconds), tile microcontroller switches to a training mode, as determined in block 110. The nlicrocontroller then performs tile training routine, as indicated in block 0 112. In the training routine, the inicrocontroller outputs a signal at output 75 which controls contact 78 to connect antenna 74 to Input 77. The rnicrocontroller also outputs a signal at output 92 which controls the output amplitude of the IF amplifier 88 to be at a low level which limits the reception range of the transceiver during the training mode. The microcontroller also controls the phase locked loop to generate those carrier frequency signals at which garage door opening inechanisin remote controls are knowil to operate (e.g., in the range between approximately 200 1MHz and 400 MHz). Microcontroiler 16 remains in the training mode until the training operation is completed., as determined in block 116.

If the actuated switch was released before the predetermined minimum time period is finished as determined in block 108, or upon completion of the training sequence as determined in block 116, or if it was determined in decision block 100 that one or more o the switches 26-28 were not actuated. rnicrocontroller 16 performs a remote transmitter detection operation. To detect Incoming data, nilcrocontroller 16 outputs a signal on 16 output 53 which controls VCO 60 to output a signal at the frequency of keyless entry transmitter 22). For example, the microcontroller outputs a signal which controls the output cirCUit to generate a signal at 3 10 MI- 1z if the RKE transmitter operates at 3 10 MHz. Microcontroller 16 also outputs a control signal at output 92, which controls the R.F input circuit IF amplifier to have a high gain, and a signal at output 75, which controls contact 75 to connect antenna 74 to input 77 of mixer 72. Microcontroller 16 then monitors input 78 to determine whether any data is being output by the comparator, as indicated in decision block 120. If data is detected, in icrocon troller 16 determines whether the data corresponds to a particular identification code stored in microcontroller 16 or whether the clata has an appropriate signal to noise ratio, as indicated in block 122. If the data corresponds to a code stored in microcontrollcr 16, the microcontroller evaluates the inputs thcreto as indicited in block- 124. The inputs evaluated include the serial bus and any other itIPLIt WhIC11 would effect how an output action is to be taken. For example, if tile serial bUS indicates that all the doors are unlocked when remote transmitter 22 command is to unlock the doors, microcontroller 16 would not have to unlock the doors. The nilcrocojitroller would effect Illumination of the vehicle interior by controlling s,witches (not shown) to connect the interior lamps (not shown) to the vehicle battery (not shown). The m1crocontroller is thus responsive to the input conditions and the control signals received frorn transmitter 22 to perform a selected output action at block 126.

FolloxJnv a decision in block 120 that data is not incoming from transmitter 20, or a decision in block 1222 that the data is not OK, or following an action in block 126, inicrocontroller 16 puts itself in a sleep mode to conserve power. In the sleep mode, the microcontroller has limited operating functions which lower the power consumption of the transceiver. In this niode, the nucrocontroller periodically monitors the inputs thereto to determine if an interrupt signal has been generated by the interrupt timer 47 or if one of the switches 26-28 has been actuated. To enter the sleep mode, microcontroller 16 first OUtpUts a reset signal at output 97 which is input to the tinier as indicated in block 128. This reinitializes the t1iner. The microcontroller then goes to sleep as indicated in block 130. When the timer expires, an external interrupt is generated thereby which interrupts the microcontroller sleep niode and microcontroller 16 returns to a fully operating state, as indicated at block 100.

Thus. it can be seen that a transceiver is disclosed which provides improved control for switching between a remote keyless entry niode and a transmitter mode. The circuit 17 has improved input amplitude control and noise suppression. Additionally, the transmitter conserves energy by operating in a sleep mode.

It will become apparent to (hose skilled in the art that various modifications to the preferred embodiment described and disclosed herein can be made. Such modifications will, however, fall within the spirit or scope of the invention as defined in the appended clainis unless the claims by their language express state otherwise.

is

Claims (7)

1. A trainable transceiver system for a vehicle, comprising: 5 an antenna; is a transceiver operable in one of a plurality of modes including a training mode and a signal transmission mode, said transceiver including an input circuit and an output circuit, said input circuit selectively receiving RP signals transmitted from an RP remote control transmitter during the training mode, and said output circuit selectively generating RP signals during the signal transmission mode for actuating a controlled device, wherein the RP signals transmitted during the signal transmission mode have learned characteristics of the RP signal received during the training mode; a switch coupled between said output circuit and said antenna, said switch having a control input at which a control signal is input which controls the state of said switch; and a controller coupled to said input circuit, to said output circuit, and to said switch, said controller controlling said switch to disconnect said output circuit from said antenna when said transceiver is operating in the training mode.

2. The trainable transceiver system as defined in claim 1, wherein said switch is coupled between said antenna and said input circuit, said switch is responsive to said controller for connecting said antenna to said input circuit when said transceiver is in the training mode.

3. The trainable transceiver system as defined in claim 2 wherein said input circuit includes a mixer having a 19 first input and said output circuit includes a variable frequency generator having an output, and wherein said output of said variable frequency generator and said first input of said mixer are coupled to respective terminals of said switch.

4. The trainable transceiver system as defined in claim 3, wherein said mixer has a second input connected to the output of said variable frequency generator.

5. The trainable transceiver system as defined in claim 4 wherein said output circuit further includes a first amplitude controller for controlling the transmission range of the transceiver.

6. The trainable transceiver system as defined in claim 5 wherein said input circuit includes a second amplitude controller for controlling the reception range of the transceiver.

7.

The trainable transceiver system as defined in claim 1, wherein said transceiver further operates in a transmitter signal detection mode for receiving RF signals from a second transmitter for controlling an accessory in the vehicle, and wherein said switch is responsive to said controller for connecting said antenna to said input circuit when said transceiver is in the transmitter signal detection mode.