AT32F425
Series Reference Manual
2022.03.30
Page 397
Ver 2.01
if
the
connected
device
supports
high-speed
communication. Do not change this bit after initial
programming.
0: FS/LS, depending on the largest speed supported by
the connected device.
1: FS/LS-only, even if the onnected device supports high-
speed.
Bit 1: 0
FSLSPCLKSEL
0x0
rw
FS/LS PHY clock select
When the controller is in FS host mode:
01: PHY clock is running at 48MHz
Others: Reserved
When the controller is in LS host mode:
00: Reserved
01: PHY clock is running at 48 MHz
10: PHY clock is running at 6 MHz. If 6 MHz clock is
selected, reset must be done by software.
11: Reserved
20.6.4.2 OTGFS host frame interval register ( OTGFS_HFIR)
This register is used to program the current
Bit
Register
Reset value
Type
Description
Bit 31: 17 Reserved
0x0000
resd
Kept at its default value.
Bit 16
HFIRRLDCTRL
0x0
rw
Reload control
This bit is used to disable/enable dynamic reload for the
host frame register at runtime.
1: Reload control disable
0: Reload control enable
This bit must be configured at initialization. Do not change
its value at runtime.
Bit 15: 0
FRINT
0xEA60
rw
Frame interval
The application uses this filed to program the interval
between two consecutive SOFs (full speed)
The number of PHY locks in this field indicates the frame
interval. The application can write a value to the host frame
interval register only after the port enable bit in the host
port control and status register has been set.
If no value is programmed, the controller calculates the
value based on the PHY clock frequency defined in the
FS/LS PHY clock select bit of the host configuration
register. Do not change the value of this field after initial
configuration.
1 ms * (FS/LS PHYPHY clock frequency) - 1
20.6.4.3 OTGFS host frame number/frame time remaining register
(OTGFS_HFNUM)
This register indicates the current frame number,and also the time remaining in the current frame (in
terms of the number of PHY clocks).
Bit
Register
Reset value
Type
Description
Bit 31: 16 FTREM
0x0000
ro
Frame time remaining
Indicates the time remaining in the current frame (FS/HS),
in terms of the number of PHY clocks. This field
decrements with the number of PHY clocks. When it
reaches zero, this filed is reloaded with the value of the
frame interval register, and a new SOF is transmiited on
the USB bus.
Bit 15: 0
FRNUM
0x3FFF
ro
Frame number
This field increments every time a new SOP is transmitted
on the USB bus, and is cleared to 0 when the value
reaches 16'h3FFF.