250
Chapter 7
Bus and Memory Control (BCU, MEMC)
Preliminary User’s Manual U17566EE1V2UM00
• Page ROM controller
– Direct connection to 8-bit/16-bit/32-bit page ROM supported
– Page ROM controller handles page widths from 8 to 128 bytes
– On-page judgement function
– Masking addresses can be changed by register setting
– Register for controlling the programmable wait during page access
– Supported page access depends on data bus width:
7.2 Description
The figure below shows a block diagram of the modules that are necessary for
accessing on-chip peripherals, external memory, or external I/O.
Figure 7-1
Bus and Memory Control diagram
Busses
The busses are abbreviated as follows:
• NPB: NEC peripheral bus
Data bus width
Supported page access
32 bit
2/4/8/16/32 x 32 bits
16 bit
4/8/16/32/64 x 16 bits
8 bit
8/16/32/64/128 x 8 bits
Intern
a
l B
us
(NPB)
B
us
Control
Unit
(BCU)
CPU
DMA
Controller
B
us
Bridge
(BBR)
V
S
B
VDB
VFB
On-chip Peripher
a
l I/O
V
S
B Fl
as
h
µ
PD70F
3
426
only
Memory
Controller
(MEMC)
A[2
3
:0]
D[
3
1:0]
BCLK
Extern
a
l
Device
µ
PD70F
3
427
only
WAIT
C
S
0
C
S
1
C
S3
C
S
4
BE0
BE1
BE2
BE
3
RD
WR
V
S
B RAM
µ
PD70F
3
426
only
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