NXP Semiconductors K22F series, Reference Manual, Page: 121 / 1407

3.8.5.1 RTC_CLKOUT signal
When the RTC is enabled and the port control module selects the RTC_CLKOUT
function, the RTC_CLKOUT signal outputs a 1 Hz or 32 kHz output derived from RTC
oscillator as shown below.
SIM_SOPT2[RTCCLKOUTSEL]
RTC_CLKOUT
RTC 1Hz clock
RTC 32kHz clock
RTC_CR[CLKO]
Figure 3-45. RTC_CLKOUT generation
3.9 Communication interfaces
3.9.1 Universal Serial Bus (USB) FS Subsystem
The USB FS subsystem includes these components:
• Dual-role USB OTG-capable (On-The-Go) controller that supports a full-speed (FS)
device or FS/LS host. The module complies with the USB 2.0 specification.
• USB transceiver that includes internal 15 kΩ pulldowns on the D+ and D- lines for
host mode functionality and a 1.5 kΩ pullup on the D+ line for device mode
functionality.
• A 3.3 V regulator (See Introduction ).
• Status detection and wakeup functions for USB data pins, VBUS pin, and OTG ID
pin.
• IRC48 with clock recovery block to eliminate the 48MHz crystal. This is available
for USB device mode only.
Chapter 3 Chip Configuration
K22F Sub-Family Reference Manual, Rev. 4, 08/2016
NXP Semiconductors 121