GB2297413A - Vehicle control system with trainable transceiver - Google Patents

Description

1 2297413 VEHICLE CONTROL SYSTEM WIT14 TRAINABLE TRANSCEIVER The invention

relates to a control system for a vehicle, and more particularly, to a system for controlling vehicle options rcsponsivc to a keyless entry remote control signal wid 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 (Rr-) control signal and a vehicle receiver xhich detects the RY control signal from the RKE transmitter to control vehicle door locks responsive thereto are well known. RF remote controls for actuating garage door mechanisms from a vehicle are also well known. These systems typically include -,cpir3tC circuitry since the garage door opening remote control is typically a transmitter %khich is niounted %vithin a housing that the car owner may store in the %ehicle. but is not integrated Into the vehicle electrical system whereas the keyless entry receiver includes an RF receiver vdiich is integrated into the vehicle electrical system. The separate circuitry is also necessary because the garage door opening mechanism 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 operation control system for a vehicle. The transceiver includes an input circuit receiving radio frequency signals from a garage door opener remote control in a traininva niode and from a separate transmitter in a transmitter detection mode. The transceiver also includes an Output circuit generating radio frequency signals for actuating a device controlled by the remote control. A controller detects signals from the input circuit and controls the output circuit %vilde an interface circuit couples the controller to the -ehicle's electrical s%steni for controlling vehicle options in response to received signals.

!\ccording to a first aspect of the invention, the input circuit includes an amplitude control v.-hich is used to ad s Just the sensitivity (i.e., reception range) ofthe tran. ceiver. According, to another aspect of the invention, the transceiver disconnects the output circuit from in antenna associated therewith when the controller is in a remote control training mode or a reception mode. According to another ispect of the invention, the controller is responsive to a first input signal to operate In a receive mode, to a second user initiated control signal to operate in a transinit 111ode, jilid to a third signal which is automatically generated for initiating reception of a signal rrorn said reniote transm i tier.

2 The systeni according to (lie invention integrates a trainable reniote control for actuating devices remote from the vehicle and a receiver to control a vehicle option responsive to a signal froni a reiliotc transmitter. The input circuit amplifier variable gain adjusts the circuit such fliat it has a significandy less sensitivity in reniote control training mode than in a transmitter signal reception niode. The system also has a significantly improved signal to noise ratio for received signals by eliminating noise which may othenvise be conveyed from the output circuit to (lie input circuit of the transceiver. The system also provides niore versatile operation, allowing user control as well as automatic posver control. thereby effecting power savings.

According to the invention there is provided a trainable transceiver system for a vehicle having an electrical system, comprising a transceiver including an inz)ut circuit for receiving radio frequency signals and an output circuit for selectively generating radio frequency signals; a connector coupled to the vehicle electrical system; a user interface including actuators for inputting first and second control signals; an 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 mode 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 said user interface, and said controller controls the transceiver to enter a transmitter signal detection mode responsive to said third control signal.

other aspects of the invention are set out in the following clauses:

3 1. 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 niode, and a transmitter signal detection mode, said transceiver including ail 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 the training niode for receiving signals frorn 10 said remote control transmitter.

I Tile transceiver systeni as defined in 1, whercin said transceiver Itirther includes an output circuit coupled to said control circuit fOr selectively generating radio frequency slonals under the control of^ said control circuit.

The transceiver s:stetii as defined In 1, wherein said variable gain amplifier c fully attenuates a sional input thereto when said trailscevver is not operating the transmitter signal detection niode or in the training mode.

4. The transceiver system as defined in 2, further including an antenna and a switch I'or selectively connecting said output circuit to said antenna, said control circuit coupled to said switch to control said switch.

5. The transceiver systeni 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 niodes including a training niode, a signal transmission mode, and a transmitter signal detection mode. said transceiver including an input circuit for receiving radio frequency signals transmitted froni a separate reniote control for a garage door opening device and the radio frequency signal transmitted from a reniote transmitter for controlling vehicle option operation, said input circuit including an aniplitude 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 xvithout (lie separate renlote control; ail interface circuit coupled to tile electrical systciii of the vehicle; and a controller coupled to said input circuit, said output circuit. and to said interface circuit, whercin when said transceiver is in a (raining inode, said controller receives signals fron- A said input circuit and stores Information about tile received signals, when said transceiver is Ail tile signal transmission mode, said controller selectively provides output control signals to said output circuit, when said transceiver is in the transmitter signal detection niode, said controller selectively provides option control signals to said interface circuit to control operation of the vellicle electrical system in response to a detected signal from the remote transmitter, and wherein sald controller provides amplitude control signals to said amplitude control input to selectiely ad.just the sensitivity ofsaid transeeiver accordijigo to (lie operating) Illode of tile transceiver.

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

8. The 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 sald gain control input such that said Input circuit has a lower sensitivity.k.licii sald transceiver is in the training mode to learn the rernote control signal from the remote control and a greater sensitivity when the transceiver i's receiving a signal from the renlote transmitter while in the transmitter signal detection mode.

6. wherein said amplitude controller 9. The transceiver systern as defined in 8, ",herein said variable gain anipliflier fully attenuates a signal input thereto when said transceiver is not In tile transmitter signal detection mode or in the training niode.

10. The transceiver system as defined in 30 includes a variable attenuator.

6, wherein said amplitude controller 1 1. The transceiver system as defined in 10, whercin said variable attenuator is coupled to sald controller, and Miercin said amplitude control signal Is Input to said variable attciltiator such that said input circuit has a lower gain when the transceiver is in (lie training niode and a higher gain when the transceiver is in the transmitter signal detection Illode.

12. Tile transceiver system as dclined ill 11, wherein said variable attenuator fully attenuates a signal input there(o when said transceiver is riot In a transmitter signal detection mode or in a training, mode.

13. The (ransceiver system as del-lned In 6. including an antenna arid a s,,.ltcli for Selectively, coilliectill', Sald olitilut circult to Sald Iiitciiiii sald controller coupled to Said s,xrltcli to Control 5.11d 14, 'Flic transceier system a., defined in is 6. ftlrtllcr ilieltidill-1 a Liser actuated ge operating modes.

selector and an interrupt timer for coil trol 1 ing, said transmitter to chang 15. A transceiver sy-steni for a velilcle, comprising an antenna, a transceiver having an input circuit arid an output circuit. said input circuit liaving an input and all Output, said input circuit selectively receiving: RF signals at said input and responsive thereto for outputting, data signals at said output. arid said output circuit selectively generating RF signais for actuating a controlled device. said output circuit having an output at which RF. signals are output.. a switch coupled between said output oF said output circuit arid said antenna. said switch having a control input at which a control signal is input which controls a state of said switeli-1 and a controller coupled to said input circuit, said OLItpUt C117CUlt and said switch, said controller controlling said s.,,,. itch to disconnect said output of said output circuit from said antenna vAien said transceiver is operating in a receive mode.

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

IT Tile trainable transceiver system as defined in 16, said input circuit includes a mixer having a First input and said output circuit includes a variable frequency 6 gcncrator having an output. and wherein said output ofsaid variable frequency generator and said First input of' slid mixer are coupled to respective lerniinals of said switch.

18. The trainable transceiver system as def-ined in 17, wherein said mixer has a second input connected to the output of -,aid variabre frequency generator.

19. The trainabic transceiver systern as def-med in 18. wherein said output circiiii, further includes a First aniplitude controller f-or controlling (lie transmission range of (lie Iransceixer.

20. Ile licklable transceiver symen as dellned ill 19, wherein said input circtlit includes a second amplitude controller i-or controlling the reception range of tile Uansceiver.

21. A tiainable transceiver systeril lor a Chicle C(.)iiiprisjii, a transceiver inelt.iile all input circuit for receiming radio frequency signals tmnsmhwd from a rernote con:-ol trallsilliller and a radio fickIllency transmitted from a second separate transmitter.

said input encuit including, a variable gain amplifier having an amphnWe control Wpm.

and.111 owpm circuit fo'- selectively generating RF si(inds transmitted to actuate a remotely controlled device skithow the reillote control transmitter, an antenna. a skitcl, for selectively connecting said antenna to sacid output circuit of said transceiver, and a control circuict coupbed to said amplitude control input and to said sivitch Tr varying the gain of said kariable gabl aniMiner to decrease the sensitivity of said input circuit of saii transceiver when in L, irliiiiil,-, mode, and for receiving signals ins said remote control and seleciixely diseminecting said output circuit frorn said antenna when said transceiver is in st reception sm:

22.

1\ manmhic transceiver sys(em lor a vehicle. comprising a tran.sceiver inciuding an MPUt Citellit for w= in-g 1Adio licqLtcncy signMs lmnsmkted From a remote control transinimer and a r.i(l;o frequency signal transmitted frorn a second transmitter, said input 7 circuit including a variable gain amplifier having in amplitude control input; an interrupt circuit having a control input, ffir selectively generating an interrupt signal; and a control circuit cotipled to said amplitude control input and said interrupt circuit, said control circuit selectively varying the gain of said variable gain amplifier to decrease tile sensitivity of' said input circuit of said transceiver when in a training mode, and said control circuit selectively placing said transceiver in a power conservative sleep state during.,liicil said transceiver is brought out of the sleep state in response to said interrupt signal.

23. The trainable transceiver system as defined in fOr iiiaiitiztiiy. Inputzing filt-st ind second control sit-inals.

24. The trainable transceiver system as deffiled in 2 further including actuators xtieretn said interrupt signal generator includes a tinier for automatically. generanne said interrupt signal a 15 predetermined tline after said control circult wes Into the sleep state.

25. A trainable transceiver system for a vehIcle comprising a transceiver including an input cit-cult ['or receiving radio frequency signals transmitted from a remote control c - c transmitter and a radio frequency signal transmitted ftom a second separate transmitter, and an output circuit for generating ignals vAilch are selectively transmitted to actuate RF st 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; an interrupt circint for selectively generating an Interrupt signal; and a control circuit coupled to said s,,, ,,itcli and to said interrupt circuit, said control circuit controlling said switch to connect said antenna to said output circuit during a receive state of said transceiver, and said control circint selectively placing the transceiver in a low power consumption mode to conserve po\.,, .er during which said transceiver returns to a full operating niode in response to an interrupt st-nal.

Z 8 26. 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 remoLe 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 is when said transceiver is in said signal detection mode.

These and other aspects, features arid advantages of the present Invention wili beconle apparent upon reading tile description thereof, together with reference to the acconipanying drawings in which.

Fig. 1 Is a pictorial vieiv of a velilcle including a transceiver according to the present Invent 101E.

Fig. 2 is a perspective view ofa receiver liousing according to the invention; Fig. 3 is an opposite perspective (.)f'3 tratiscelxer housIn-e according to Fig. 2.

FW, 4 is a circuit schematic of [lie transceiver according to the invention shown 'in block diagrani form; and Fig- 5 is a now diagrain of the program for controlling the operation of the transceixer according to Fig. 4.

Referring initially to Figs. 1-3. a vellicle 8 ils illustrated including iver 12 a transcei according. to the invention. The invention is integrated into a sniall, generally. square niodule housing 10. Housing 10 encloses a transceiver 12 (Fig. 4) whicil selectively transmits coded radio frequency (R.F.) energy, as indicated by arrow... 1- to a device controlled by an RF control signal. such as a garage door opening mechanism 14 shown in block forin In I-iLs. 1 and 4. Tile convent lonal garage door opening ineclianism 14 9 includes a receiver and control circuit (not shown) which responds to the control signal "I"' for opening and closing a garage door. Transceiver 12 includes a programmable microcontrolicr 16 (Fig. 4) which controls an RF output circuit 18 to generate signal 'T.". Signal "T" has a frequency and code learned frorn signal "B" transmitted by existing remote control transmitter 20 and identified by transceiver 12 in a training mode. The transceiver, after learning the carrier frequency, format and code of signal T," can transmit remote control signal "T" to activate the 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 "C from keyless entry remote control 22. An RF. input circuit 19 demodulates signal "C and outputs control signals to the vehicle electrical system responsive thereto. For example, the keyless entry remote control may control vehicle door locks. a trunk lock and a gas door cover. Responsive to signal "K," the microcontroller outputs a control signal to serial bus 24 which controls the vehicle accessories or options according to the input control code.

Housing 10 is small, such that it may be integrated into a variety of accessories in the vehicle, such as in a rearview mirror, an overhead console, a map light, a visor, the instrument panel. or any other suitable location in [lie vehicle. The transmitter includes three s.,,,ttclies 26, 27 and 28 in a front panel face 30. Each switch is associated with a respective channel, and each channel stores a respective RI. 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, t-,.,,o 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 held 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 held for longer than the predetermined time period, microcontroller 16 will enter the training mode for the co"ntrol channel associated with that held 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 vdien the training mode is Finished.

It i's 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 the 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 tile 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 the vehicle electrical system.

Although the overall preferred niounting environment is described with respect to the generally square housing 10. transceiver 12 according to tile Invention may be used in other environments. F-or example, the improved transmitter of the immediate invention may be used as an integral part of a rearview nlirror 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 microcontroller 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 the vehicle electrical s,,steni. An RF signal input circuit 19 and the RF signal output circuit 18 are connected to inicrocontroller 16 for receiving and transmitting RF signals.

The user input 46 (Fig. 4) and the 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 i-node for the trainable transceiver 12 (Fig. 4) which controls device 14 without rernote 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-numeric 12 display. The alpha-numeric display would providc 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. Tile phase locked loop circuit 51 is implemented using any suitable integrated circuit such as the Motorola MC145106, driven by ail 8 MFIz oscillator. The phase locked loop 51 is responsive to the frequency selection signals at output 57 of inicrocontroller 16 to generate a DC signal at output 59.

The output signal at output 59 of tile phase locked loop circuit 51 is filtered in lowpass filter 54. The output ol' the lowpass filter is connected to a switch 56. Switch 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 sarnple-and-liold circuit may be implemented using any suitable means such as an IC No. 4066 switch, a capacitor and an amplifier.

The output of saniple-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-andhold circuit 58. The VCO includes a switch (not shown), which may be implemented using a transistor, and %vhich 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 rernote control training mode.

The signal output by VCO 60 is filtered in lowpass filter 65. The amplitude of the signal output by the lo%&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 microcontroller 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 tile control of microcontroller 16. 'File 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. ail input 69 or phase 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 momentarily 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, tile 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 WO 60. Accordingly, the VCO 60 will generate a stable output signal during tile frequency interval. The output of buRcr 62 is ail oscillating signal having a carrier frequency set by the signal on parallel data bus 52.

c The transceivcr 12 iilcltidc., in antenna 74 which is connected to contact 76 of switch 70. Switch 70 is coupled to output 75 of microcontroller 16. The s'-vitch may be implemented by any suitable switch such as a relay driven by the output signal of microcontroller 16. Switch 70 is controlled by signals from nilcrocontroller 16 such that the contact 76 connects anteniia 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 whicil 20 would otherwise result from tile coupling of the input and output circuits.

Although transceiver 12 preferably includes a single antenna 74. those skilled in the art will recognize that two antennae (not shown) could be used: one for the RF signal input circuit and one for the RF signal outputcircuit. 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 given 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 mixer 72 is filtered by bandpass filter 84. The bandpass filter 84 removes noise from the output of tile mixer 72. The filtered signal is input to ail intermediate frequency amplifier 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 amplifier with a variable feedback impedance. The gain control input signal varies the amplifier gain between three levels. Ilie 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 frorn remote control 20. The IF amplifier 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 within a radius of approximately I 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 inode, for inputting a signal from transmitter 22, the gain of amplifier 88 is controlled to provide the transceiver with a significantly greater sensitivity. This allows transceiver 12 to detect a signal from a keyless entry transmitter 22 while the user is still several car lengths away from vehicle 8 (Figg. I). When transceiver 12 (Fig. 4) is not in the training niode or the transmitter detection niode. the gain of tile IF amplifier can be controlled to be at Substantially OdB, to prevent noise from the receive cIrCL1it being input to controller 16.

The output of the IF aniplifier 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 OL1tpUt from the demodulator 93 to a fixed reference signal. If the output of demodulator 93 exceeds tile 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 microcontrolier 16.

The interrupt circuit, or sleep tinier, 47 is connected to input 98 and output 97 of rnicrocontroller 16. The sleep tinier is connected to input 98 of microcontroller 16. Sleep tinier 70 is implemented using any suitable low power consumption tinier which outputs a timer interrupt signal a predetermined time period after it is reset by the reset signal from microcontroller 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 'A'III now be described with reference to Fig. 5 and the circuit of Fig. 4. Microcontroller 16 initiates transmit/receive state control following ail external interrupt generated by the sleep timer 47, upon power-up of rnicrocontroller 16. or when one of switches 26-28 is actuated. Microcontroller 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 transmit/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, microcontrollcr 16 de(ermines that the transmitter was powered up or that interrupt tinier 47 generated an interrupt signal, as indicated in block 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 whicil controls the phase locked loop 50 to output a DC signal which drives (lie WO 60 to have a desired carrier frequency which was previously stored in association with the one of the switches 26-28 which is actuated. Microcontroller 16 also outputs a data signal at output 63 which 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 tilicrocontroller 16 determines that the switch is actuated for longer than a predetermined minimum time period (e.g., 5 seconds), the microcontroller switches to a training mode, as determined in block 110. The microcontroller then performs the traininer routine, as indicated in block 112. In the training routine, the microcontroller outputs a signal at output 75 which controls contact 78 to connect antenna 74 to input 77. The nilcrocontroller 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.

Tile microcontroller also controls the phase locked loop to gencrate those carrier frequency signals at which garage door opening mechanism remote controls are known to operate (e.g., in the range between approximately 200 MHz and 400 MHz). Microcontroller 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 deterniined in decision block 100 that one or more of the switches 26-28 were riot actuated, microcontroller 16 performs a remote transmitter detection operation. To detect incoming data, microcontroller 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 microcontrollcr outputs a signal which controls the output circuit to generate a signal at 3 10 MHz if the RKE transmitter operates at 310 MHz. Microcontroller 16 also outputs a control signal at output 92, which controls the RF 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, microcontroller 16 determines whether the data corresponds to a particular identification code stored in microcontroller 16 or whether the data has an appropriate signal to noise ratio, as indicated in block 122. If the data corresponds to a code stored in microcontroller 16, the microcontroller evaluates the inputs flicreto as indicated in block 124. The inputs evaluated include the serial bus and any other input which 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 U11lock tile doors, microcontroller 16 would not have to unlock the doors.

The nilcrocontroller would effect illumination of the vehicle interior by controlling s%vitches (not shown) to connect the interior lamps (not shown) to tile vehicle battery (not shown). The microcontroller is thus responsive to the input conditions and the control signals received from transmitter 22 to perform a selected output action at block 126.

Following a decision in block 120 that data is not incoming from transmitter 220, or a decision in block 1222 that the data is not OK, or following an action 11i block 126, microcontroller 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 microcontroller periodically monitors the inputs thereto to determine if in interrupt signal has been generated by tile interrupt timer 47 or if one of the switches 26-28 has been actuated. To enter the sleep mode, microcontroller 16 first ClUtputs a reset signal at output 97 vAlich is input to the tinier as indicated in block 128.

This reinitializes the tijner. 'File microcontroller then goes to sleep as indicated in block 130. When the timer expires, an external interrupt is generated thereby which interrupts the nlicrocontrolier 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 mode 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 those 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 claims unless tile claims by their language express state otherwise.

18 CILAIM is 1. A trainable transceiver system for a vehicle having an electrical system, comprising a transceiver including an input circuit for receiving radio frequency signals and an output circuit for selectively generating radio frequency signals; a connector coupled to the vehicle electrical system; a user interface including actuators for inputting first and second control signals; an 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 mode 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 said user interface, and said controller controls the transceiver to enter a transmitter signal detection mode responsive to said third control signal.

2. The transceiver system as defined in claim 1, wherein said interrupt signal generator includes an interrupt timer which periodically generates an interrupt signal to which said interrupt signal generator responds by generating said third control signal.

3. The transceiver system as defined in claim 2, wherein said controller initializes said interrupt timer upon entering a sleep mode whereby said interrupt timer interrupts the sleep mode automatically at the end of a sleep interval by generating said interrupt signal.

19 4. The transceiver system as defined in claim 3, wherein said user interface includes at least one switch.

5. The transceiver system as defined in claim 4, wherein said first control signal is generated when said switch is held for a first predetermined time period.

6. The transceiver system as defined in claim 5 wherein said second control signal is generated when said switch is held for a second predetermined time period.

7. The transceiver system as defined in claim 6 wherein said controller controls said transceiver to enter a transmitter signal detection mode following said training mode or said transmit mode.

is