HD6412350 Hitachi, HD6412350 Datasheet - Page 207

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

6.10.4
Figure 6-37 shows the timing for transition to the bus-released state.
Address bus
HWR, LWR
Data bus
[1]
[2]
[3]
[4]
[5]
BREQ
BACK
Transition Timing
RD
AS
ø
Low level of BREQ pin is sampled at rise of T
BACK pin is driven low at end of CPU read cycle, releasing bus to external
bus master.
BREQ pin state is still sampled in external bus released state.
High level of BREQ pin is sampled.
BACK pin is driven high, ending bus release cycle.
Figure 6-37 Bus-Released State Transition Timing
T
0
CPU cycle
T
Address
1
[1]
Minimum
1 state
T
2
[2]
External bus released state
[3]
2
state.
High impedance
High impedance
High impedance
High impedance
High impedance
[4]
[5]
cycle
CPU
187