Detailed Product Description

☞ GENERAL DESCRIPTION

The HMNR1288D(V) TIMEKEEPER SRAM is a 128Kb x 8 non-volatile static RAM and real
time clock organized as 131,072 words by 8 bits. The special DIP package provides
a fully integrated battery back-up memory and real time clock solution. The HMNR1288D(V)
directly replaces industry standard 128Kbit x 8 SRAMs. It also  provides
the non-volatility of Flash without any requirement for special WRITE timing
or limitations on the number of WRITEs that can be performed.

☞FEATURES
■ YEAR 2000 COMPLIANT 
■ INTEGRATED LOW POWER SRAM, REAL TIME CLOCK, POWER-FAIL CONTROL CIRCUIT, BATTERY
and CRYSTAL
■ BCD CODED YEAR, MONTH, DAY, DATE, HOURS, MINUTES, and SECONDS  
■ AUTOMATIC POWER-FAIL CHIP DESELECT and WRITE PROTECTION VOLTAGES : 
(VPFD = Power-fail Deselect Voltage)
– HMNR1288D : VCC = 4.5 to 5.5V
4.2V ≤ VPFD ≤ 4.5V
– HMNR1288DV: VCC = 3.0 to 3.6V
2.7V ≤ VPFD ≤ 3.0V
■ CONVENTIONAL SRAM OPERATION : UNLIMITED WRITE CYCLES 
■ SOFTWARE CONTROLLED CLOCK CALIBRATION FOR HIGH ACCURACY APPLICATIONS
■ 10 YEARS OF DATA  RETENTION and CLOCK OPERATION IN THE ABSENCE OF POWER 
PIN and FUNCTION COMPATIBLE WITH INDUSTRY STANDARD 128K x 8 SRAMS
■ SELF-CONTAINED BATTERY and CRYSTAL IN DIP PACKAGE
■ BATTERY LOW WARNING FLAG
■ SOFTWARE CONTROLLED CLOCK CALIBRATION   
   FOR HIGH ACCURACY APPLICATIONS
■ MICROPROCESSOR POWER-ON RESET 
(Valid even during battery back-up mode)
■ PROGRAMMABLE ALARM OUTPUT ACTIVE IN  
BATTERY BACK-UP MODE

       

1) Do cut down  8 byte from exiting area of SRAM memory and reset memory area, For
example, if Dallas's DS1747 assign  524,208byte for SRAM memory area, You should
do reset memory area as a 524,272byte for HMNR5128D which is compatible parts.

2) According to Register Map, the way of setting for Timekeeper register and Read
is same as  that of Dallas  except only  the setting for Century Registert.  Though
DS1747for Century Register is  located on 7FFF8h, Hanbit's  HMNR5128D is located
on 7FFF1h. So, You do setting Century Register to correspond with HMNR5128D.
Regarding Battery flag Register, Though DS1747 is  located on 7FFFCh, HMNR5128D
is  located on 7FFF0h of Data4. So, you do adjust it according to what HMNR5128D
has.