UPD16661A View Datasheet(PDF) - NEC => Renesas Technology
Part Name
Description
Manufacturer
UPD16661A Datasheet PDF : 36 Pages
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µPD16661A
3. DATA BUSES
The method for lining up byte data on the data bus line is essentially the Little Endian system adopted by NEC
and Intel Corp.
3.1 16-bit data bus (BMODE = L)
Byte unit access
The address setting direction →
is as shown on the right.
Word unit access
The address setting direction →
is as shown on the right.
D0 to D7
00000H
00002H
00004H
:
:
D8 to D15
00001H
00003H
00005H
:
:
D0 to D7
D8 to D15
00000H
00002H
00004H
:
:
For access from the system to be performed in word units (16 bits), or byte units (8 bits), /UBE (upper-byte
enable) and A0 are used to show whether valid data is in the bytes of either (or both) D0 to D7 or D8 to D15.
/CS
/OE
/WE /UBE
A0
MODE
I/O
D0 to D7
D8 to D15
H
X
X
X
X
Not selected
Hi-z
Hi-z
L
L
H
L
L
Read
L
H
H
L
Dout
Hi-z
Dout
Dout
Dout
Hi-z
L
H
L
L
L
Write
L
H
H
L
Din
Din
X
Din
Din
X
L
H
H
X
X
Output
L
X
X
H
H
disable
Hi-z
Hi-z
Hi-z
Hi-z
Remark X : Don’t care, Hi-z : High impedance
7
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