DS1688 Datasheet | Dallas Semiconductor

.. DS1688/DS1691 DS1688/DS1691 3 Volt/5 Volt Serialized Real Time Clock with NV RAM Control Features Incorporates industry standard DS1287 PC clock plus enhanced Features : PIN ASSIGNMENT VBAUX X1 X2 RCLR AD0 AD1 AD2 AD3 AD4 AD5 AD6 AD7 PWR GND 1 2 3 4 5 6 7 8 9 10 11 12 13 14 28 27 26 25 24 23 22 21 20 19 18 17 16 15 CEI CEO VCCI VCCO SQW VBAT IRQ PSEL RD GND WR ALE CS KS VBAUX X1 X2 RCLR AD0 AD1 AD2 AD3 AD4 AD5 AD6 AD7 PWR GND 1 2 3 4 5 6 7 8 9 10 11 12 13 14 28 27 26 25 24 23 22 21 20 19 18 17 16 15 CEI CEO VCCI VCCO SQW VBAT IRQ PSEL RD GND WR ALE CS KS - +3 or +5 volt operation - 64- bit Silicon serial number - 64- bit customer specific ROM or additional serial number available control circuitry supports system power on from date/time alarm or key closure battery backup and write protection to external SRAM 12.5 pF crystal - Power - Automatic - Crystal select bit allows RTC to operate with 6 pF or - 114 bytes user NVRAM - Auxiliary battery input - RAM clear input - Century register - 32 KHz output for power management - 32- bit VCC powered elapsed time counter - 32- bit VBAT powered elapsed time counter - 16- bit power cycle counter - patible with functions existing BIOS for original DS1287 DS1688 28- PIN DIP (600 MIL) VBAUX NC NC RCLR AD0 AD1 AD2 AD3 AD4 AD5 AD6 AD7 PWR GND 1 2 3 4 5 6 7 8 9 10 11 12 13 14 28 27 26 25 24 23 22 21 20 19 18 17 16 15 DS1688S 28- PIN SOIC (330 MIL) CEI CEO VCCI VCCO SQW NC IRQ PSEL RD NC WR ALE CS KS DS1691 28- PIN ENCAPSULATED PACKAGE (740 MIL) - Available as chip (DS1688) or stand- alone module with embedded battery and crystal (DS1691) PIN DESCRIPTION X1 X2 RCLR AD0-AD7 PWR KS CS ALE WR RD VCCO - - ...