资 源 简 介
The DS17285, DS17485, DS17885, DS17287, DS17487,and DS17887 real-TIme clocks (RTCs) are designed to besuccessors to the industry-standard DS12885 andDS12887. The DS17285, DS17485, and DS17885 (hereafterreferred to as the DS17x85) provide a real-TImeclock/calendar, one TIme-of-day alarm, three maskableinterrupts with a common interrupt output, a programmablesquare wave, and 114 bytes of battery-backed NVSRAM. The DS17x85 also incorporates a number ofenhanced funcTIons including a silicon serial number,power-on/off control circuitry, and 2k, 4k, or 8kbytes ofbattery-backed NV SRAM. The DS17287, DS17487, andDS17887 (hereafter referred to as the DS17x87) integratea quartz crystal and lithium energy source into a 24-pinencapsulated DIP package. The DS17x85 and DS17x87power-control circuitry allows the system to be poweredon by an external stimulus such as a keyboard or by atime-and-date (wake-up) alarm. The PWR output pin istriggered by one or either of these events, and is used toturn on an external power supply. The PWR pin is undersoftware control, so that when a task is complete, the systempower can then be shut down.
