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3. SPEclFlcATloNs
/MELSEC
(1) The installation of a ROM shifts the corresponding RAM
address range t o a different channel. (e.g. Installing 8K of
ROM at channel 1 addresses 8000H t o BFFFH moves the
RAM area t o channel 3 addresses 8000H t o BFFH.
(2) Two shorting pins are used t o specify RAM or ROM
in
channels 1 and 2. The RAM area is moved as follows
depending on the pin setting i n each channel.
With
ROM
Without
ROM
I
I
RAM position
I
RAM and ROM areas
coincide.
I
Correct
I
I
The
RAM
area changer
ROM
position
Correct
channels as though
ROM war
installed.
(3)
Only 24K bytes are valid (addresses 8000H t o DFFFH)
when 16K ROM is used.
The 8K bytes from EOOOH t o FFFH are used in the
RAM area and this address range in the ROM cannot be
accessed.
(4) For RAM area memory protect, refer t o Section 4.3.1
(page 4-5).
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