Samsung OFFICESERV 7100 Service Manual page 41

OfficeServ 7100 Service Manual
SRAM
2-Mbyte SRAM is provided and the SRAM consists of two 1-Mbyte elements. The SRAM
has the memory backup function and stores various DB information. However, the DB
information for the system operation should be also stored in the multimedia card to store
data safely. To do so can store the DB information even if the system is damaged fatally
from the outside.
Real Time Clock
RTC72423 of Seiko is used as the real time clock to provide the system clock.
MMC Driver (TE4300)
The MMC driver is used for the control the external multimedia card.
TE4300 of Tokyo Electronics is used as the MMC driver to connect the CPU interface and
the MMC bus.
Multimedia Card (MMC Card)
The multimedia card is the NAND flash memory card and is used as the auxiliary storage
unit and the voice main file storage. 256-MByte multimedia card is currently used. Since it
accesses the system through the MMC bus in high-speed 1-bit serial bus access mode, it
does not need the change of the hardware even if the capacity is increased. The card should
be always installed to the system for its operation. The card should be wrapped in vinyl
used in the purchase of the card for the preservation.
Internal Music
One channel is provided for the internal sound source of the system. CODEC supports both
A-LAW method and U-LAW method and the relevant CODEC is operated by the hardware
logic. The internal sound source is readily changed into an external sound source by using
MMC.
Analog Phase Locked Loop (APLL)
The OfficeServ 7100 uses an analog PLL. The reference clock of 8 kHz is specified by
software. If the external source of the reference clock is not specified, the clock created
internally is used as the reference clock. The external reference clock of 8 kHz is set by the
system automatically and a specific board can be specified by using the MMC if necessary.
In this case, the specification of the board slot connected the most stable digital line is
required.
Watch Dog
Watch Dog is the function to restart the system when the system is malfunctioned.
The system is designed to be restarted when the system is malfunctioned for a certain time.
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