at91rm3400 ATMEL Corporation, at91rm3400 Datasheet - Page 400

• Manufacturer Part Number: at91rm3400
• Description: Atmel Advanced At91 Arm Microcontroller
• Manufacturer: ATMEL Corporation

USB Bus Transactions
USB Transfer Event
Definitions
400
AT91RM3400
Each transfer results in one or more transactions over the USB bus. There are five kinds of
transactions flowing across the bus in packets:
1. Setup Transaction
2. Data IN Transaction
3. Data OUT Transaction
4. Status IN Transaction
5. Status OUT Transaction
As shown in Table 70, transfers are sequential events carried out on the USB bus.
Table 70. USB Transfer Events
Notes:
Control Transfers
Interrupt IN Transfer
(device toward host)
Interrupt OUT Transfer
(host toward device)
Isochronous IN Transfer
(device toward host)
Isochronous OUT Transfer
(host toward device)
Bulk IN Transfer
(device toward host)
Bulk OUT Transfer
(host toward device)
1. Control transfer must use endpoints with no ping-pong attributes.
2. Isochronous transfers must use endpoints with ping-pong attributes.
3. Control transfers can be aborted using a stall handshake.
(1) (3)
(2)
(2)
•
•
•
•
•
•
•
•
•
Setup transaction > Data IN transactions >
Status OUT transaction
Setup transaction > Data OUT transactions >
Status IN transaction
Setup transaction > Status IN transaction
Data IN transaction > Data IN transaction
Data OUT transaction > Data OUT transaction
Data IN transaction > Data IN transaction
Data OUT transaction > Data OUT transaction
Data IN transaction > Data IN transaction
Data OUT transaction > Data OUT transaction
1790A–ATARM–11/03