
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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