DS1687-5+ Maxim Integrated Products, DS1687-5+ Datasheet - Page 17

• Manufacturer Part Number: DS1687-5+
• Description: IC RTC 5V 64-BIT Y2K 24-EDIP
• Manufacturer: Maxim Integrated Products
• Type: Clock/Calendar/NVSRAM/Y2Kr

Specifications of DS1687-5+

• Memory Size: 242B
• Time Format: HH:MM:SS (12/24 hr)
• Date Format: YY-MM-DD-dd
• Interface: Parallel
• Voltage - Supply: 4.5 V ~ 5.5 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Through Hole
• Package / Case: 24-DIP (600 mil) Module
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 4. Update-Ended And Periodic-Interrupt Relationship
EXTENDED FUNCTIONS
The extended functions provided by the DS1685/DS1687 that are new to the RAMified RTC family are accessed by
a software-controlled bank-switching scheme, as illustrated in Figure 5. In bank 0, the clock/calendar registers and
50 bytes of user RAM are in the same locations as for the DS1287. As a result, existing routines implemented
within BIOS, DOS, or application software packages can gain access to the DS1685/DS1687 clock registers with
no changes. Also in bank 0, an extra 64 bytes of RAM are provided at addresses just above the original locations
for a total of 114 directly addressable bytes of user RAM.
UIP
PF
UF
t
t
PI
BUC
= PERIODIC INTERRUPT TIME INTERNAL PER TABLE 3.
= DELAY BEFORE UPDATE CYCLE = 244s.
t
BUC
17 of 34
1 second
t
PI
t
PI/2
DS1685/DS1687 3V/5V Real-Time Clocks
t
PI/2