GENERAL
This system provides the vehicle owner with compass, temperature, trip computer
information, tire pressure information(PSI), and integrated Homelink. The Homelink and
tire pressure portions of the circuit are separate from the compass section, except that the
compass microprocessor controls the power to the Homelink section and the tire
pressure section. The compass microprocessor also serially communicates to the
Homelink/PSI microprocessor which switch has been pressed and the Homelink/PSI
microprocessor communicates back the tire pressure information to the compass
microprocessor for display to the driver. The following information refers to the
Homelink part of the system and also to the PSI part of the system.
Homelink Operational Description
This system gives the vehicle owner the ability to use a garage door opener (GDO) that is
integral to the interior trim of the vehicle. The Homelink shall be capable of learning and
remembering variables required to emulate three different GDO transmitters. In the learn
mode of operation, the user selects one of three channels. The Homelink determines
the frequency, data and, where applicable, the Rolling Code manufacturer of the original
GDO transmitter (OT). The frequency and data stream or rolling algorithm parameters
(created within the OT's Rolling Code guidelines) are then stored in non-volatile memory
(NVM) for use in the transmit mode of operation. Once contained in memory, the
Homelink shall activate the given receiver by repeating, at the proper frequency, either a
fixed data stream or a hopping data stream created with the OT's Rolling Code algorithm.
Homelink Transmit Mode of Operation
If a selected channel has been previously trained, the HomeLink shall operate in
transmit mode. To operate the Homelink in the transmit mode, the user shall activate
one of three transmit buttons. The Compass microprocessor shall determine which button
has been activated and send the information serially to the Homelink microprocessor,
which shall generate appropriate data at the proper frequency.
The VFD indicator shall be ON continually during transmit mode.
The VFD indicator shall rapidly blink (4Hz ± 10%) for 2 ± 10% seconds followed by
continuous illumination during Rolling Code PWM transmissions.
The HomeLink will continue in the transmit mode for twenty (20 ± 10%) seconds before
proceeding to the learning mode of operation.
Homelink Default Mode of Operation
If a selected channel has never been previously trained nor previously erased, the
Homelink shall operate in default mode. To operate the Homelink in the default mode,
the user shall activate one of three transmit buttons. The HomeLink shall determine
which button has been activated, and using a pre-determined identification code and
frequency (see Appendix B for details) shall transmit such data with the VFD indicator
continually on. The HomeLink will continue in the default mode for twenty (20 ± 10%)
seconds before proceeding to the learning mode of operation.
Homelink Rolling Code Default Mode of Operation
The user places the Homelink in rolling code default mode by simultaneously holding
down buttons one, two, and three for 30 ± 10% seconds.
