Preliminary - Information Subject to Change - 9/24/98
5 - 4
EZ-USB Development Board
Circuit Details
The EZ-USB I
2
C bus is connected to two 8-bit IO expander chips
(Philips PCF8574) and an EEPROM used for USB device
identification, EZ-USB boot loads and 8051 access. The EEPROM
is socketed (8-pin DIP) to allow the use of various EEPROM
densities.
Figure 5-1: EZ-USB Development Board Components
A N 2 1 3 1 Q
U 1
3 2 K x8
R A M
U 2
3 2 K x8
R A M
A [1 5 ..0 ]
D [7 ..0 ]
A
[1
4
..0
]
A
[1
4
..0
]
2 2 V 1 0
P L D
E A , C E 1 # , C E 2 # , R D 1 # , R D 2 #, P F [3 ..0 ]
C E 1#
R D 1#
C E 2#
R D 2#
P C 6 /W R #
A
[15.
.12]
P C 7 /R D #
P S E N #
P A [7 ..0 ], P B [7 ..0 ], P C [7 ..0 ], C LK 2 4 , B K P T , W U #
P C F 8 5 7 4
U 1 1
P C F 8 5 7 4
U 1 2
E E P R O M
1 2 M H z
M M 1 ,M M 0
M M 1 ,M M 0
R S -2 3 2 L ev e l
C o nv e rte r
3
4
7
8
1
2
5
6
S IO -0
S IO -1
E
x
pans
io
n
C
onnec
to
rs
P
1
-P
5
J P 1
3 .3 V
R e g u la to r
3
2
1
3
2
1
E X T 5 V (J2 )
5V
N C
G N D
U S B (J 1 )
P in 1
3 .3 V
5 V
P C 1
TxD 0
P C 0
R xD 0
P B 3
TxD 1
P B 2
R xD 1
S C L
S D A
S 2 -S 5
S 6 x,S 7 x
S A 0 ,S A 1
W U #
W A K E U P #
P W R
S e le c t
(J 4 )
