CHAPTER 3 CPU FUNCTION
109
User’s Manual U14492EJ3V0UD
3.4.10 Specific registers
Specific registers are registers that are protected from being written with illegal data due to inadvertent program
loop (runaway), etc. The V850E/IA1 has three specific registers, the power save control register (PSC) (refer to
8.5.2
Control registers
), clock control register (CKC) (refer to
8.3.4 Clock control register (CKC)
), and flash
programming mode control register (FLPMC) (refer to
16.7.12 Flash programming mode control register
(FLPMC)
).
3.4.11 System wait control register (VSWC)
Set the following values to this register according to the operating frequency used.
This register can be read/written in 8-bit units (address: FFFFF06EH, initial value: 77H).
Remark
If the timing of changing the flag or count value conflicts with the timing of accessing a register when a
register including a status flag that indicates the status of an on-chip peripheral function (such as ASIF0)
or a register indicating the count value of a timer (such as TM0n) is accessed, a register access retry
operation is performed. As a result, a longer time may be required to access the on-chip peripheral I/O
register.
Operating Frequency (f
XX
)
Setting Value of VSWC
4 MHz
≤
f
XX
< 32 MHz
11H
32 MHz
≤
f
XX
≤
50 MHz
12H
3.4.12 Cautions
When using the V850E/IA1, the following registers must be set from the beginning.
•
System wait control register (VSWC)
(See
3.4.11 System wait control register (VSWC)
)
•
Clock control register (CKC)
(See
8.3.4 Clock control register (CKC)
)
After setting VSWC and CKC, set other registers as required.
Содержание V850E/IA1 mPD703116
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