PSB21473FV13XT Infineon Technologies, PSB21473FV13XT Datasheet - Page 540

• Manufacturer Part Number: PSB21473FV13XT
• Manufacturer: Infineon Technologies

Specifications of PSB21473FV13XT

• Operating Supply Voltage (typ): 3.3V
• Operating Supply Voltage (min): 3.135V
• Operating Supply Voltage (max): 3.6V
• Operating Temp Range: 0C to 70C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 144
• Lead Free Status / RoHS Status: Compliant

Data Sheet
22.8
22.8.1
The bus enumeration process consists of an interrogation sequence through which the
USB host acquires information from the connected device, gives it an unique address,
and assigns it a configuration value. In the simplest form, the process takes four steps:
Step 1: The host issues a Get_Descriptor command to the device through the default
address using the control pipe. The device then provides information about itself, such
as device class, vendor id, maximum packet size for endpoint 0, etc.
Step 2: The host sends an unique address in a data packet to the device using the
Set_Address command. The device, under software control, gets the address through
endpoint 0 and stores it.
Step 3: The host requests and reads the device configuration descriptor using the
Get_Configuration command. The device responds with information about the number
of interfaces and endpoints, endpoint transfer type, packet size and direction, maximum
power requirements, power source, etc.
Step 4: The last step of the enumeration process is handled using the Set_Configuration
command through which the host assigns a configuration value to the device.
After the enumeration process is complete, the device is configured and ready for USB
data transmit and receive transactions.
22.8.2
A control transfer consists of at least two and perhaps three stages. This chapter gives
a short description of these stages of a control transfer and the associated control and
status bits.
22.8.2.1 Setup Stage
A control transfer always begins with a setup stage that transfers information to a target
device, defining the type of request being made to the USB device. The standard
commands except the Set_Descriptor, Get_Descriptor and Synch_Frame commands
are typically handled by the USB module automatically without CPU interaction (please
refer also to
a setup interrupt ( SUI) indicates the end of a setup phase. Additionally, the status and
control bits UBF (USB Buffer Full), CBF (CPU Buffer Full) and SOD (Start of Data) are
reset.
22.8.2.2 Data Stage
This stage occurs only for requests that require data transfers. The direction of this data
stage is always predicted to be from Host to Device (bit EPBSn.DIRn is automatically
USB Device Framework
Enumeration Process
Control Transfers
page
562). If the command is not handled by the USB module automatically,
540
USB Module
PSB 21473
2003-03-31
INCA-D