M30622MA-XXXFP RENESAS [Renesas Technology Corp], M30622MA-XXXFP Datasheet - Page 293

• Manufacturer Part Number: M30622MA-XXXFP
• Description: 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY
• Manufacturer: RENESAS [Renesas Technology Corp]

Protect
278
Operation
2.1.2 Protect Operation
The following explains the protect operation. Figure 2.1.2 shows the set-up procedure.
(1) Setting “1” in the write-enable bit of system clock control registers 0 and 1 causes system
(2) The contents of system clock control register 0 and that of system clock control register 1 are changed.
(3) Setting “0” in the write-enable bit of system control registers 0 and 1 causes system clock
(4) To change the contents of processor mode register 0 and that of processor mode register 1,
(5) The write-enable bit of port 9 direction register and SI/Oi control register (i=3,4) goes to “0”
clock control register 0 and system clock control register 1 to be in write-enabled state.
control register 0 and system control register 1 to be in write-inhibited state.
follow the same steps as in dealing with system clock control registers.
when the next write instruction is executed after write-enabled state is readied. Make
changes in input/output and SI/Oi control register (i=3,4) immediately after the instruction that
sets “1” in the write-enable bit of port P9 direction register and SI/Oi control register
(i=3,4)(avoid causing an interrupt). Also take measures to prevent DMA transfer from being
executed.
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Mitsubishi microcomputers
M16C / 62 Group