at43usb355 ATMEL Corporation, at43usb355 Datasheet - Page 75

• Manufacturer Part Number: at43usb355
• Description: At43usb355 Full-speed Usb Microcontroller With Embedded Hub, Adc And Pwm
• Manufacturer: ATMEL Corporation

Control Transfers at
Control End-point EP0
2603G–USB–04/06
The description given below is for the function control end-point, but applies to the hub control
end-point as well if the proper registers are used.
The following illustration describes the three possible types of control transfers – Control
Write, Control Read and No-data control:
The following state diagram shows how the various state transitions are triggered. Additional
decision making may take place within the response states to determine the next expected
state. Unmarked arcs represent transitions that trigger immediately following completion of the
response state processing. Stable states, those requiring an interrupt to exit having no
unmarked arcs as exit paths, are shown in bold.
Control
Write
Control
Read
No-data
Control
RX_OUT_INT
SETUP(0)
SETUP(0)
SETUP(0)
Setup
Setup
Stage
DATA0
DATA0
Stage
DATA0
TX_COMPLETE_INT
Write Status
Response
Control
Write Data
Response
Control
DATA1(0)
OUT(1)
RX_OUT_INT
Status
DATA1
DATA1
Stage
IN(1)
IN(1)
TX_COMPLETE_INT
(
ANY STABLE STATE
RX_SETUP_INT
TX_COMPLETE_INT
Response
Read Status
Response
Setup
Control
Idle
RX_OUT_INT
OUT(0)
IN(0)
Stage
DATA0
DATA0
Data
)
TX_COMPLETE_INT
Read Data
DATAn
DATA1(0)
Response
Control
…
…
OUT(0/1)
DATA0/1
DATA0/1
IN(0/1)
Data packet with PID’s
data toggle bit equal to n
Zero length DATA1 packet
Legend:
Response
No-data
Status
AT43USB355
DATA1(0)
DATA1(0)
Status
OUT(1)
Stage
IN(1)
IN(1)
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