| 摘要 |
An electrical product uses a small battery, which is permanently soldered into the product, to protect certain critical circuits such as volatile memory when primary power is removed. The life of such a battery is extended by disabling it during the time interval between factory testing and first use by a customer so that it does not drain during transportation and storage. During factory testing, instructions stored in volatile memory are delivered to a microprocessor that cause it to generate a unique signal that resets a switch and thereby disables the battery. These instructions are down-loaded into the volatile memory and executed as part of the final factory test procedure. When the primary power source is removed from the product following factory test, these instructions are lost (erased) because the battery is disabled at this time. The microprocessor is arranged to set the switch, and thereby enable the battery, each time primary power is subsequently applied or removed from the product.
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