71
Pin Functions
Chapter 2
Preliminary User’s Manual U17566EE1V2UM00
2.4.3
External memory interface of µPD70F3427
The µPD70F3427 is equipped with an external memory interface. The data
bus width can be chosen between 16-bit D[15:0] and 32-bit D[31:0].
The signals of the external memory interface are partly shared with ports
respectively alternative functions and are controlled by different means, as
listed in
Table 2-21
.
The upper data bus lines D[31:16] are made available by setting
PMC.PMC143 = 1. Thus this bit changes the interface from 16- to 32-bit mode.
All other bus interface signals are available via group 14 (also usable as 3-bit I/
O port) and the permanent MEM-I/F group.
Table 2-21
External memory interface pin control
Port
Ext. memory I/F
signal
Mode control
Group
Name
Port/alternative
Ext. Memory I/F
3
P32
D18
PMC.PMC143 = 0
PMC.PMC143 = 1
P33
D19
8
P86
D17
P87
D18
9
P90
D24
P91
D25
P92
D26
P93
D27
P94
D28
P95
D29
P96
D30
P97
D31
10
P104
D20
P105
D21
P106
D22
P107
D23
14
P140
BCLK
PMC.PMC140 = 0
PMC.PMC140 = 1
P141
BE2
PMC.PMC141 = 0
PMC.PMC141 = 1
P142
BE3
PMC.PMC142 = 0
PMC.PMC142 = 1
MEM-I/F
–
A[23:0]
–
permanent
D[15:0]
WR
CS0, CS1,
CS3, CS4
RD
WAIT
BE0, BE1
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