Rainbow-electronics DS1558Y Manual de usuario Pagina 1

1 of 18 072402 Note: Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of

DS155810 of 18Figure 4. BACKUP MODE ALARM WAVEFORMSUSING THE WATCHDOG TIMERThe watchdog timer can be used to detect an out-of-control processor. The u

DS155811 of 18ABSOLUTE MAXIMUM RATINGS*Voltage Range on Any Pin Relative to Ground -0.3V to +6.0VStorage Temperature Range -55°C to +125°CSoldering Te

DS155812 of 18DC ELECTRICAL CHARACTERISTICS (VCC = +3.3V ±10% or +5V ±10%, TA = -40°C to +85°C)PA

DS155813 of 18READ CYCLE, AC CHARACTERISTICS (VCC = +3.3V ±10% or +5V ±10%, TA = -40°C t

DS155814 of 18WRITE CYCLE, AC CHARACTERISTICS (VCC = +3.3V ±10% or +5V ±10%, TA = -40°C

DS155815 of 18Figure 7. WRITE CYCLE TIMING, CHIP-ENABLE CONTROLLED

DS155816 of 18POWER-UP/DOWN CHARACTERISTICS (VCC = +5V ±10%, TA = -40°C to +85°C)PARAMETER SYMBOL MIN TYP MAX UNITS NOTESCE or WE at VIH,Bef

DS155817 of 18POWER-UP/DOWN CHARACTERISTICS (VCC = +3.3V ±10%, TA = -40°C to +85°C)PARAMETER SYMBOL MIN TYP MAX UNITS NOTESCE or WE at VIH,Befo

DS155818 of 18AC TEST CONDITIONSOutput Load: 25pFInput Pulse Levels: 0V to +3VTiming Measurement Reference Levels:Input: +1.5VOutput: +1.5VInput Pul

DS15582 of 18TYPICAL OPERATING CIRCUITDESCRIPTIONThe DS1558 is a full function, year 2000-compliant (Y2KC), real-time clock/calendar with an RTCalarm,

DS15583 of 18programmed limits. The DS1558 power-on reset can be used to detect a system power-down or failureand hold the CPU in a safe reset state u

DS15584 of 18RST – This pin is an output used to signal that VCC is out of tolerance. On power-up, RST is held low fora period of time to allow the

DS15585 of 18Table 1. OPERATING MODESVCCCE OE WEDQ0–DQ7 MODE POWERVIHX X High-Z Deselect StandbyVILXVILDINWrite ActiveVILVILVIHDOUTRead ActiveVCC >

DS15586 of 18BATTERY LONGIVITYThe battery lifetime is dependent on the RAM battery standby current and the DS1558 internal clockoscillator current. Th

DS15587 of 18CLOCK OPERATIONSTable 2 and the following paragraphs describe the operation of the RTC, alarm, and watchdog functions.Table 2. DS1558 REG

DS15588 of 18READING THE CLOCKWhen reading the RTC data, it is recommended to halt updates to the external set of double-bufferedRTC registers. This p

DS15589 of 18Table 3. ALARM MASK BITSAM4 AM3 AM2 AM1 ALARM RATE1111Once per second1110When seconds match1100When minutes and seconds match1000When hou