| 摘要 |
A low-cost, low-power, half-duplex communication system provides data transfer to and/or from an electronic watch or similar small electronic device. To accommodate the small size of the watch housing, data transfer is achieved using an infrared photodiode as a detector and an LED as an infrared emitter, directly coupled to the watch microcontroller with a minimum of additional components. Due to the small battery power capacity of electronic watches, the communication system is designed to have a negligible standby power consumption as well as low power consumption during data transfer. The IR emitter is connected directly to an output port on the microcontroller and the IR detector is connected to an input port on the microcontroller through a transistor amplifier. In standby mode, the microcontroller ports render the infrared devices and the transistor non-conducting to minimize power consumption. During transfer of information to and from the watch, the watch is placed in a cradle associated with a computing device and containing an infrared detector and an infrared emitter, designed so that the IR devices in the watch and cradle align in pairs when the watch is placed in the cradle.
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