SAM3A4C Atmel Corporation, SAM3A4C Datasheet - Page 1097

• Manufacturer Part Number: SAM3A4C
• Manufacturer: Atmel Corporation

39.5.3.8
39.5.3.9
39.5.3.10
11057A–ATARM–17-Feb-12
11057A–ATARM–17-Feb-12
Remote Wake-up
Management of Control Pipes
Management of IN Pipes
and to send a SET_ADDRESS (addr) SETUP request with the new address to be used by the
device. Once this SETUP transaction is over, the user writes the new address into the USB Host
Address for Pipe x field in the USB Host Device Address register (HSTADDR.HSTADDRPx). All
following requests, on all pipes, will be performed using this new address.
When the host controller sends a USB reset, the HSTADDRPx field is reset by hardware and the
following host requests will be performed using default device address 0.
The controller host mode enters the Suspend state when the UOTGHS_HSTCTRL.SOFE bit is
written to zero. No more “Start of Frame” is sent on the USB bus and the USB device enters the
Suspend state 3 ms later.
The device awakes the host by sending an Upstream Resume (Remote Wake-Up feature).
When the host controller detects a non-idle state on the USB bus, it sets the Host Wake-Up
interrupt (UOTGHS_HSTISR.HWUPI) bit. If the non-idle bus state corresponds to an Upstream
Resume (K state), the Upstream Resume Received Interrupt (UOTGHS_HSTISR.RXRSMI) bit
is set. The user has to generate a Downstream Resume within 1 ms and for at least 20 ms by
writing a one to the Send USB Resume (UOTGHS_HSTCTRL.RESUME) bit. It is mandatory to
w r i t e
UOTGHS_HSTCTRL.RESUME to enter the Ready state, else UOTGHS_HSTCTRL.RESUME
will have no effect.
A control transaction is composed of three stages:
The user has to change the pipe token according to each stage.
For the control pipe, and only for it, each token is assigned a specific initial data toggle
sequence:
IN packets are sent by the USB device controller upon IN requests from the host. All data which
acknowledges or not the bank can be read when it is empty.
The pipe must be configured first.
When the host requires data from the device, the user has to select beforehand the IN request
m o d e w i t h t h e I N R e q u e s t M o d e b i t i n t h e P i p e x I N R e q u e s t r e g i s t e r
(UOTGHS_HSTPIPINRQx.INMODE):
• SETUP
• Data (IN or OUT)
• Status (OUT or IN)
• SETUP: Data0
• IN: Data1
• OUT: Data1
• When UOTGHS_HSTPIPINRQx.INMODE is written to zero, the UOTGHS will perform (INRQ
• When UOTGHS_HSTPIPINRQx.INMODE is written to one, the UOTGHS will perform IN
+ 1) IN requests before freezing the pipe.
requests endlessly when the pipe is not frozen by the user.
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