Datasheet

1061
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
39.5.1.5 Speed Control
Device mode
When the USB interface is in device mode, the speed selection (full-speed or high-speed) is performed
automatically by the UOTGHS during the USB reset according to the host speed capability. At the end of the USB
reset, the UOTGHS enables or disables high-speed terminations and pull-up.
It is possible to restraint the UOTGHS to full-speed or low-speed mode by handling the UOTGHS_DEVCTRL.LS
and the Speed Configuration (UOTGHS_DEVCTRL.SPDCONF) bits in UOTGHS_DEVCTRL.
Host mode
When the USB interface is in host mode, internal pull-down resistors are connected on both D+ and D- and the
interface detects the speed of the connected device, which is reflected by the Speed Status
(UOTGHS_SR.SPEED) field.
39.5.1.6 DPRAM Management
Pipes and endpoints can only be allocated in ascending order, from the pipe/endpoint 0 to the last pipe/endpoint to
be allocated. The user shall therefore configure them in the same order.
The allocation of a pipe/endpoint x starts when the Endpoint Memory Allocate bit in the Endpoint x Configuration
register (UOTGHS_DEVEPTCFGx.ALLOC) is written to one. Then, the hardware allocates a memory area in the
DPRAM and inserts it between the x-1 and x+1 pipes/endpoints. The x+1 pipe/endpoint memory window slides up
and its data is lost. Note that the following pipe/endpoint memory windows (from x+2) do not slide.
Disabling a pipe, by writing a zero to the Pipe x Enable bit in the Pipe Enable/Reset register
(UOTGHS_HSTPIP.PENx), or disabling an endpoint, by writing a zero to the Endpoint x Enable bit in the Device
Endpoint register (UOTGHS_DEVEPT.EPENx), resets neither the UOTGHS_DEVEPTCFGx.ALLOC bit nor its
configuration:
 the Pipe Banks (UOTGHS_HSTPIPCFGx.PBK) field,
the Pipe Size (UOTGHS_HSTPIPCFGx.PSIZE) field,
the Pipe Token (UOTGHS_HSTPIPCFGx.PTOKEN) field,
the Pipe Type (UOTGHS_HSTPIPCFGx.PTYPE) field,
the Pipe Endpoint Number (UOTGHS_HSTPIPCFGx.PEPNUM) field,
and the Pipe Interrupt Request Frequency (UOTGHS_HSTPIPCFGx.INTFRQ) field;
 the Endpoint Banks (UOTGHS_DEVEPTCFGx.EPBK) field,
the Endpoint Size (UOTGHS_DEVEPTCFGx. EPSIZE) field,
the Endpoint Direction (UOTGHS_DEVEPTCFGx.EPDIR) field,
and the Endpoint Type (UOTGHS_DEVEPTCFGx.EPTYPE) field.
To free its memory, the user shall write a zero to the UOTGHS_DEVEPTCFGx.ALLOC bit. The x+1 pipe/endpoint
memory window then slides down and its data is lost. Note that the following pipe/endpoint memory windows (from
x+2) do not slide.