HD6412350 Hitachi, HD6412350 Datasheet - Page 184

• Manufacturer Part Number: HD6412350
• Description: (HD6412350 / HD6432351) 16-BIT MICROCONTROLLER
• Manufacturer: Hitachi

6.5.8
Wait Control
There are two ways of inserting wait states in a DRAM access cycle: program wait insertion and
pin wait insertion using the WAIT pin.
Program Wait Insertion
When the bit in ASTCR corresponding to an area designated as DRAM space is set to 1, from 0 to
3 wait states can be inserted automatically between the T
state and T
state, according to the
c1
c2
settings of WCRH and WCRL.
Pin Wait Insertion
When the WAITE bit in BCRH is set to 1, wait input by means of the WAIT pin is enabled
regardless of the setting of the AST bit in ASTCR. When DRAM space is accessed in this state, a
program wait is first inserted. If the WAIT pin is low at the falling edge of ø in the last T
or T
c1
w
state is inserted. If the WAIT pin is held low, T
state, another T
states are inserted until it goes
w
w
high.
Figure 6-17 shows an example of wait state insertion timing.
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