NXP Semiconductors K22F series, Reference Manual, Page: 137 / 1407

In VLPS mode, the module behaves as it does in stop mode if VLPS mode is entered
from run mode. However, if VLPS mode is entered from VLPR mode, the FIFO might
underflow or overflow before wakeup from stop mode due to the limits in bus bandwidth.
In VLPW and VLPR modes, the module is limited by the maximum bus clock
frequencies.
When operating from an internally generated bit clock or Audio Master Clock that is
disabled in stop modes:
In Stop mode, if the Transmitter Stop Enable (TCSR[STOPE]) bit is clear, the transmitter
is disabled after completing the current transmit frame, and, if the Receiver Stop Enable
(RCSR[STOPE]) bit is clear, the receiver is disabled after completing the current receive
frame. Entry into Stop mode is prevented–not acknowledged–while waiting for the
transmitter and receiver to be disabled at the end of the current frame.
3.9.6.3.2 Low-leakage modes
When entering low-leakage modes, the Stop Enable (TCSR[STOPE] and
RCSR[STOPE]) bits are ignored and the SAI is disabled after completing the current
transmit and receive Frames. Entry into stop mode is prevented (not acknowledged)
while waiting for the transmitter and receiver to be disabled at the end of the current
frame.
3.10 Human-machine interfaces
3.10.1 GPIO configuration
This section summarizes how the module has been configured in the chip. For a
comprehensive description of the module itself, see the module’s dedicated chapter.
Chapter 3 Chip Configuration
K22F Sub-Family Reference Manual, Rev. 4, 08/2016
NXP Semiconductors 137