USB on-the-go high-speed (OTG_HS)
RM0090
1418/1731
DocID018909 Rev 11
35.12.3 Host-mode
registers
Bit values in the register descriptions are expressed in binary unless otherwise specified.
Host-mode registers affect the operation of the core in the host mode. Host mode registers
must not be accessed in peripheral mode, as the results are undefined. Host mode registers
can be categorized as follows:
OTG_HS host configuration register (OTG_HS_HCFG)
Address offset: 0x400
Reset value: 0x0000 0000
This register configures the core after power-on. Do not change to this register after
initializing the host.
Bits 31:16
INEPTXFD:
IN endpoint TxFIFO depth
This value is in terms of 32-bit words.
Minimum value is 16
Maximum value is 512
The power-on reset value of this register is specified as the largest IN endpoint FIFO
number depth.
Bits 15:0
INEPTXSA:
IN endpoint FIFOx transmit RAM start address
This field contains the memory start address for IN endpoint transmit FIFOx. The address
must be aligned with a 32-bit memory location.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
Reserved
FSLSS
FS
L
S
P
C
S
r
rw rw
Bits 31:3 Reserved, must be kept at reset value.
Bit 2
FSLSS:
FS- and LS-only support
The application uses this bit to control the core’s enumeration speed. Using this bit, the
application can make the core enumerate as an FS host, even if the connected device
supports HS traffic. Do not make changes to this field after initial programming.
0: HS/FS/LS, based on the maximum speed supported by the connected device
1: FS/LS-only, even if the connected device can support HS (read-only)
Bits 1:0
FSLSPCS:
FS/LS PHY clock select
When the core is in FS host mode:
01: PHY clock is running at 48 MHz
Others: Reserved
When the core is in LS host mode:
00: Reserved
01: PHY clock is running at 48 MHz.
10: Select 6 MHz PHY clock frequency
11: Reserved
Note: The FSLSPCS bit must be set on a connection event according to the speed of the
connected device. A software reset must be performed after changing this bit.