CHAPTER 5 CLOCK GENERATOR
Preliminary User’s Manual U16846EJ1V0UD
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(7) System wait control register (VSWC)
This register is used to control wait states when a high-speed CPU and a low-speed peripheral I/O are
connected.
VSWC can be set by a 1-bit or 8-bit memory manipulation instruction.
RESET input clears this register to 00H.
Figure 5-8. Format of System Wait Control Register (VSWC)
0
Symbol
VSWC
0
0
PAW0
0
0
0
PDW0
Address: FFFDH After reset: 00H R/W
PDW0
0
No wait
One wait state inserted
1
Control of system clock data wait
PAW0
0
No wait
One wait state inserted
1
Control of system clock address wait
Cautions 1. Be sure to insert one wait state if the minimum instruction execution
time is 0.2
µ
s or less (f
XP
= 10 MHz or more).
2. Do not access VSWC in the current IE environment (IE-78K0-NS, IE-
78K0-NS-A, and IE-78K0K1-ET).
3. Be sure to clear bits 1 to 3 and 5 to 7 to 0.