6.1.2 Block Diagram
Figure 6-1 shows a block diagram of the bus controller.
Figure 6-1 Block Diagram of Bus Controller
0
CS
to
CS
ABWCR
ASTCR
WCER
CSCR
Chip select
control signals
BACK
BREQ
WAIT
Internal
address bus
Area
decoder
Bus control
circuit
Wait-state
controller
Internal data bus
Legend
ABWCR:
ASTCR:
WCER:
WCR:
BRCR:
CSCR:
Bus width control register
Access state control register
Wait state controller enable register
Wait control register
Bus release control register
Chip select control register
CPU bus request signal
DMAC bus request signal
Refresh controller bus request signal
CPU bus acknowledge signal
DMAC bus acknowledge signal
Refresh controller bus acknowledge signal
Internal signals
WCR
BRCR
Bus arbiter
7
Bus mode control signal
Bus size control signal
Access state control signal
Wait request signal
Internal signals
112
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