
RM0008
USB on-the-go full-speed (OTG_FS)
Doc ID 13902 Rev 12
837/1096
Bit 8
SRPCAP:
SRP-capable
The application uses this bit to control the OTG_FS controller’s SRP capabilities. If the core
operates as a non-SRP-capable
B-device, it cannot request the connected A-device (host) to activate V
BUS
and start a session.
0: SRP capability is not enabled.
1: SRP capability is enabled.
Note: Accessible in both device and host modes.
Bit 7
PHYSEL:
Full Speed serial transceiver select
This bit is always 1 with write-only access.
Bits [6:3] Reserved
Bits [2:0]
TOCAL:
FS timeout calibration
The number of PHY clocks that the application programs in this field is added to the full-speed
interpacket timeout duration in the core to account for any additional delays introduced by the
PHY. This can be required, because the delay introduced by the PHY in generating the line
state condition can vary from one PHY to another.
The USB standard timeout value for full-speed operation is 16 to 18 (inclusive) bit times. The
application must program this field based on the speed of enumeration. The number of bit
times added per PHY clock is 0.25 bit times.