Cypress Semiconductor FX2LP Technical Information Page 61

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Chapter 2. Endpoint Zero Page 2-7
2.3.1 Get Status
The USB Specification defines three USB status requests. A fourth request, to an interface, is
declared in the spec as “reserved.” The four status requests are:
Remote Wakeup (Device request)
Self-Powered (Device request)
Stall (Endpoint request)
Interface request (reserved)
The FX2 automatically asserts the SUDAV interrupt to tell the firmware to decode the SETUP
packet and supply the appropriate status information.
Figure 2-4. Data Flow for a Get_Status Request
I
N
A
D
D
R
E
N
D
P
C
R
C
5
Token Packet
D
A
T
A
0
8 bytes
Setup
Data
C
R
C
1
6
Data Packet
S
E
T
U
P
A
D
D
R
E
N
D
P
C
R
C
5
Token Packet
D
A
T
A
1
2
Bytes
C
R
C
1
6
Data Packet
D
A
T
A
1
Data Pkt
A
C
K
H/S Pkt
O
U
T
A
D
D
R
E
N
D
P
C
R
C
5
Token Packet
C
R
C
1
6
SETUP Stage
SUTOK
Interrupt
SUDAV
Interrupt
DATA Stage
STATUS Stage
8 RAM
bytes
SETUPDAT
IN0BUF
64-byte
Buffer
2
IN0BC
A
C
K
H/S Pkt
A
C
K
H/S Pkt
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