
MC68F375
STATIC RANDOM ACCESS MEMORY (SRAM)
MOTOROLA
REFERENCE MANUAL
Rev. 25 June 03
11-7
Note that a long word write will be completed coherently only if the reset occurs during
the second write bus cycle. If reset occurs during the first write bus cycle, only the first
word will be written to the SRAM array and the second write will not be allowed to
occur. In this case, the long word data contained in the SRAM will not be coherent. The
first word will contain the most significant half of the new long word information and the
second word will contain the least significant half of the old long word information.
If a reset is generated by an asynchronous reset such as the loss of clocks or software
watchdog time-out, the contents of the standby SRAM array are not guaranteed.
11.4.4 STOP Operation
consuming state. The register block may still be accessed to allow the STOP control
bit to be cleared and the array base address registers to be updated, see 11.3.2 Array When in stop mode, the SRAM array can not be read or written. All data in the array
will be retained. Switching to VSTBY will occur as normal if VDDL drops below its spec-
ified value when the SRAM module is in stop mode.
11.4.5 Overlay Operation
The four 512-byte SRAM blocks can be used independently of the main 8K SRAM
array. The blocks can be initialized to be continuous with the main array or can be used
to overlay the flash module. The overlay feature is enabled whenever an overlay
SRAM module base address is mapped over the flash array address space. The 512-
byte SRAM block should be placed on a 512-byte boundary and will respond to any
access to the overlayed section of the flash and will disable the flash contents from
being read.
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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