PORT A INTERFACE
MOTOROLA
PORT A
4 - 7
Figure 4-5 shows a system that uses internal program memory loaded from an external
$2800
U3
U4
A11
A12
OE
R/W
CS
A15
V
CC
+5 V
RD
WR
PS
DS
X/Y
BN
BR
BG
WT
BS
V
SS
GROUND
ADDRESS BUS
A0 - A15
DATA BUS
D0 - D23
DSP56002
BUS
CONTROL
$3FFF
EXTERNAL
PROGRAM
X AND Y MEMORY
16
24
A0-A10
A13
A14
U1
CE
A11
4K
PROGRAM
MEMORY
$3000
$2FFF
2K
X DATA
MEMORY
$27FF
2K
Y DATA
MEMORY
$2000
24 BITS
U2
Figure 4-4 Memory Segmentation
PS
DS
X/Y
External Memory Reference
1
1
1
No Activity
1
0
1
X Data Memory on Data Bus
1
0
0
Y Data Memory on Data Bus
0
1
1
Program Memory on Data Bus (Not an Exception)
0
1
0
External Exception Fetch: Vector or 1
(Development Mode Only)
0
0
X
Reserved
1
1
0
Reserved
Table 4-1 Program and Data Memory Select Encoding
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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