System ram, Memory, Cmos ram – Lynx EPM-4 User Manual

Page 34: Clearing cmos ram, Default cmos ram setup values, Real time clock, Setting the clock

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CPU

Reference – 26

EPM-4 Reference Manual

CPU

The ÉlanSC520 Microcontroller has a 32-bit, low-voltage AMD Am5x86 microprocessor at its
core. The maximum clock rate is 133 MHz. The Am5x86 has 16 kb of unified cache that supports
write-back and write-through policies. It is a high-performance 486 CPU achieving performance
results equal to a Pentium 75.

System RAM

M

EMORY

The EPM-4 has 64MB of SDRAM soldered on board.

• Storage Capacity

64 MB

• Voltage

3.3

Volt

• Error Detection Code Not supported
• Error Correction

Not supported

• Speed

66 MHz, 60 ns

CMOS RAM

C

LEARING

CMOS

RAM

Jumper V1 can be moved to position [1-2] for 30 seconds to erase the contents of the CMOS
RAM. Be sure to move the jumper back to position [2-3] for normal operation.

Note:

Operation of the board with jumper V1 in the erase position [1-2] is not supported
or recommended.

D

EFAULT

CMOS

RAM

S

ETUP

V

ALUES

After the CMOS RAM is cleared, the system will load default CMOS RAM parameters the next
time the board is powered on. The default CMOS RAM setup values will be used in order to boot
the system whenever the main CMOS RAM values are blank, or when the system battery is dead
or has been removed from the board.

Real Time Clock

The EPM-4 features a year 2000 compliant, battery-backed 146818 compatible real time
clock/calendar chip. Under normal battery conditions, the clock will maintain accurate
timekeeping functions during periods when the board is powered off.

S

ETTING THE

C

LOCK

The CMOS Setup utility (accessed by pressing the [DEL] key during a system boot) can be used
to set the time/date of the real time clock.

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