-8
AT89RFD-11 User Guide
7648A–USB–06/06
3.5
Memory
The target memory used with this reference design is a Nand Flash memory (Micron
M29F2G08AAB) of 256 MBytes. This memory allow the user to save and exchange data
and files with any PC.
The Nand Flash memory is connected to the AT89C5131A-M as below. P0 and P2 ports
are mandatory in order to access the Nand Flash using MOVX instructions.
Figure 3-5.
Nand Flash memory interface
3.6
USB
3.6.1
Multiple
Enumeration
(composite device)
Thanks to its seven endpoints, the AT89C5131A-M can manage several USB devices
simultanuously using the multiple enumerations functionality (composite device). This
functionnality allows the user to declare one device with several interfaces. Each inter-
face is seen and managed as a stand-alone device from the PC point of view. In our
case we declare two interfaces: one to manage the mass storage device and the other
to manage the HID mouse device.
To be able to manage two interfaces, the microcontroller should have at the least a con-
trol endpoint and the sum of the endpoints required by both interfaces. For example for
this reference design we need 1 endpoint for control transfer, 1 endpoint for mouse and
2 endpoints for mass storage, which means that we need 4 endpoints to make this
application.
P 0. 0
P 0. 1
P 0. 2
P 0. 3
P 0. 4
P 0. 5
P 0. 6
P 0. 7
A V s s
V s s
Xt al2
Xt al1
24
MHz
2 2 p F
2 2 p F
100
27
27
1.5k
D-
D+
V ref
P LLF
1 0 n F
2 .2 n F
I / O . 0
I / O . 1
I / O . 2
I / O . 3
I / O . 4
I / O . 5
I / O . 6
I / O . 7
M i C R O N
M 29F 2G 08A A B
A T 89C 5131A -M
V s s
P 2. 0
P 2. 1
CLE
A LE
U S B c o n n e c to r
3. 3V
regulat or
D-
D+
V bus
GND
2.2k
Vcc
Vcc
R/B
1 0 µ F
T a n ta l.
P 3. 7
P 2. 3
P 2. 4
VDD
A V D D
1µF
1 0 0 n F
V c c
P 3. 3
Vcc
EA
100k
P 3. 0
W ri te
P ro te c ti o n
2.2k
WE
CE
RE
P 3. 6
PSEN
ISP
2.2k
o p ti o n a l
1 0 µ F
T a n ta l.
10k
Vcc
WP
U c ap
