M30622M4 MITSUBISHI [Mitsubishi Electric Semiconductor], M30622M4 Datasheet - Page 49

• Manufacturer Part Number: M30622M4
• Description: SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
• Manufacturer: MITSUBISHI [Mitsubishi Electric Semiconductor]

Protection
Protection
Figure 1.13.6. Protect register
The protection function is provided so that the values in important registers cannot be changed in the event
that the program runs out of control. Figure 1.13.6 shows the protect register. The values in the processor
mode register 0 (address 0004
ister 0 (address 0006
dress 03F3
only be changed when the respective bit in the protect register is set to “1”. Therefore, important outputs
can be allocated to port P9.
If, after “1” (write-enabled) has been written to the port P9 direction register and SI/Oi control register
(i=3,4) write-enable bit (bit 2 at address 000A
reverts to “0” (write-inhibited). However, the system clock control registers 0 and 1 write-enable bit (bit 0 at
000A
to “0” after a value has been written to an address. The program must therefore be written to return these
bits to “0”.
16
Protect register
b7
) and processor mode register 0 and 1 write-enable bit (bit 1 at 000A
b6
16
b5
) , SI/O3 control register (address 0362
b4
b3
b2
16
b1
), system clock control register 1 (address 0007
b0
Note: Writing a value to an address after “1” is written to this bit returns the bit
Bit symbol
Nothing is assigned.
In an attempt to write to these bits, write “0”. The value, if read, turns out to be
indeterminate.
16
PRC0
PRC1
PRC2
Symbol
PRCR
), processor mode register 1 (address 0005
to “0” . Other bits do not automatically return to “0” and they must therefore
be reset by the program.
Enables writing to processor mode
registers 0 and 1 (addresses 0004
and 0005
Enables writing to port P9 direction
register (address 03F3
control register (i=3,4) (addresses
0362
Enables writing to system clock
control registers 0 and 1 (addresses
0006
16
16
and 0366
16
and 0007
16
), a value is written to any address, the bit automatically
)
Address
000A
Bit name
16
16
16
) and SI/O4 control register (address 0366
) (Note
)
16
16
) and SI/Oi
)
XXXXX000
When reset
16
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
0 : Write-inhibited
1 : Write-enabled
0 : Write-inhibited
1 : Write-enabled
0 : Write-inhibited
1 : Write-enabled
2
16
), port P9 direction register (ad-
16
16
) do not automatically return
), system clock control reg-
Function
Mitsubishi microcomputers
M16C / 62 Group
R
W
16
) can
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