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4. CPU MODULE
4.5.3 Settings for memory write protect switch
Memory write protect switch is to prevent a program from overwriting and deleting by an
operation from the peripheral device.
It is used to prevent overwriting and deletion of a program after the program is created.
To modify the ROM memory, cancel the memory write protect (OFF).
The memory write protect is set to OFF as factory default.
(1) When using the A1SJHCPU(S8) or the A1SHCPU
With the A1SJHCPU(S8)/A1SHCPU, ON/OFF setting of memory write protect is set
using the DIP switch (SW-2).The first 32 Kbytes in the user memory area of 64
Kbytes are fixed.
When operating using an E
2
PROM, the setting of the memory write protect switch is
effective to the E
2
PROM if a memory cassette is installed.
Furthermore, pograms cannot be written to the built-in RAM using peripheral devices
while operating the E
2
PROM.
By selecting the ON position on this switch, the parameters, program and a part of
extension file register is write-protected in the memory. (Refer to Section 4.2.2.)
(2) When using the A2SHCPU
The memory write protect range can be changed by setting the DIP switches for
memory write protect.
ON
OFF
1
5
2
3
4
Range of Memory Protection (k bytes) Setting Switch
0 to 16 1:ON
16 to 32 2:ON
32 to 48 3:ON
48 to 64 4:ON
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