USBx_CLK_RECOVER_CTRL field descriptions (continued)
Field
Description
0
Reserved
This field is reserved.
Default should not be changed
42.4.30 IRC48M oscillator enable register
(USBx_CLK_RECOVER_IRC_EN)
Controls basic operation of the on-chip IRC48M module used to produce nominal
48MHz clocks for USB crystal-less operation and other functions.
See additional information about the IRC48M operation in the Clock Distribution
chapter.
Address: 4007_2000h base + 144h offset = 4007_2144h
Bit
7
6
5
4
3
2
1
0
Read
Write
Reset
0
0
0
0
0
0
0
1
USBx_CLK_RECOVER_IRC_EN field descriptions
Field
Description
7–2
Reserved
This field is reserved.
1
IRC_EN
IRC48M enable
This bit is used to enable the on-chip IRC48Mhz module to generate clocks for crystal-less USB. It can be
used for FS USB device mode operation. This bit must be set before using the crystal-less USB clock
configuration.
0
Disable the IRC48M module (default)
1
Enable the IRC48M module
0
REG_EN
IRC48M regulator enable
This bit is used to enable the local analog regulator for IRC48Mhz module. This bit must be set if user
wants to use the crystal-less USB clock configuration.
0
IRC48M local regulator is disabled
1
IRC48M local regulator is enabled (default)
Chapter 42 Universal Serial Bus Full Speed OTG Controller (USBFSOTG)
K22F Sub-Family Reference Manual , Rev. 3, 7/2014
Freescale Semiconductor, Inc.
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