REJ03B0166-0113 Rev.1.13
Aug 21, 2009
3803 Group (Spec.H QzROM version)
MISRG
(1) Bit 0 of address 001016: Oscillation stabilizing time
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 = 0116, Prescaler 12 = FF16) are
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 001016).
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.
(2) Bits 1, 2, 3 of address 001016: Middle-speed Mode
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 (003B16) --> start main clock
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.
Middle-speed mode automatic switch by program
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 001016) to “1” in the condition that the middle-
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
001016).
Fig 10. Structure of MISRG
MISRG
MISRG: address 001016)
b7
b0
Oscillation stabilizing time set after STP instruction
released bit
0 : Automatically set “0116” to Timer 1, “FF16” to
Prescaler 12
1 : Automatically set disabled
Middle-speed mode automatic switch set bit
0 : Not set automatically
1 : Automatic switching enabled (Note)
Middle-speed mode automatic switch wait time set bit
0 : 4.5 to 5.5 machine cycles
1 : 6.5 to 7.5 machine cycles
Middle-speed mode automatic switch start bit
(Depending on program)
0 : Invalid
1 : Automatic switch start (Note)
Not used (return “0” when read)
(Do not write “1” to this bit)
Note : When automatic switch to middle-speed mode from low-speed mode occurs,
the values of CPU mode register (3B16) change.