M38039G4H-XXXHP RENESAS [Renesas Technology Corp], M38039G4H-XXXHP Datasheet - Page 14

• Manufacturer Part Number: M38039G4H-XXXHP
• Description: SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
• Manufacturer: RENESAS [Renesas Technology Corp]

3803 Group (Spec.H QzROM version)
Rev.1.10
REJ03B0166-0110
MISRG
(1) Bit 0 of address 0010
(2) Bits 1, 2, 3 of address 0010
Fig 9.
set after STP instruction released bit
When the MCU stops the clock oscillation by the STP
instruction and the STP instruction has been released by an
external interrupt source, usually, the fixed values of Timer 1
and Prescaler 12 (Timer 1 = 01
automatically reloaded in order for the oscillation to
stabilize. The user can inhibit the automatic setting by setting
“1” to bit 0 of MISRG (address 0010
However, by setting this bit to “1”, the previous values, set
just before the STP instruction was executed, will remain in
Timer 1 and Prescaler 12. Therefore, you will need to set an
appropriate value to each register, in accordance with the
oscillation stabilizing time, before executing the STP
instruction.
Figure.9 shows the structure of MISRG.
Automatic Switch Function
In order to switch the clock mode of an MCU which has a
sub-clock, the following procedure is necessary:
set CPU mode register (003B
oscillation --> wait for oscillation stabilization --> switch to
middle-speed mode (or high-speed mode).
However, the 3803 group (Spec.H QzROM version) has the
built-in function which automatically switches from low to
middle-speed mode by program.
Structure of MISRG
b7
Note : When automatic switch to middle-speed mode from low-speed mode occurs,
Nov 14, 2005
the values of CPU mode register (3B
16
: Oscillation stabilizing time
Page 14 of 91
16
16
16
, Prescaler 12 = FF
: Middle-speed Mode
) --> start main clock
16
).
b0
16
16
) are
) change.
MISRG
MISRG: address 0010
• Middle-speed mode automatic switch by program
Oscillation stabilizing time set after STP instruction
released bit
Middle-speed mode automatic switch set bit
Middle-speed mode automatic switch wait time set bit
Middle-speed mode automatic switch start bit
(Depending on program)
Not used (return “0” when read)
(Do not write “1” to this bit)
0 : Automatically set “01
1 : Automatically set disabled
0 : Not set automatically
1 : Automatic switching enabled (Note)
0 : 4.5 to 5.5 machine cycles
1 : 6.5 to 7.5 machine cycles
0 : Invalid
1 : Automatic switch start (Note)
The middle-speed mode can also be automatically switched
by program while operating in low-speed mode. By setting
the middle-speed automatic switch start bit (bit 3) of MISRG
(address 0010
speed mode automatic switch set bit is “1” while operating in
low-speed mode, the MCU will automatically switch to
middle-speed mode. In this case, the oscillation stabilizing
time of the main clock can be selected by the middle-speed
automatic switch wait time set bit (bit 2) of MISRG (address
0010
Prescaler 12
16
).
16
) to “1” in the condition that the middle-
16
PRELIMINARY
Notice: This is not a final specification.
Some parametric limits are subject to change.
)
16
” to Timer 1, “FF
16
” to