NXP Semiconductors K22F series, Reference Manual, Page: 652 / 1407

The MCU must not read from the flash memory while commands are running (as
evidenced by CCIF=0) on that block. Read data cannot be guaranteed from a flash block
while any command is processing within that block. The block arbitration logic detects
any simultaneous access and reports this as a read collision error (see the
FSTAT[RDCOLERR] bit).
29.4.7 Read While Write (RWW)
The following simultaneous accesses are allowed:
• The user may read from one logical program flash memory space while flash
commands are active in the other logical program flash memory space.
Simultaneous operations are further discussed in Allowed Simultaneous Flash
Operations .
29.4.8 Flash Program and Erase
All flash functions except read require the user to setup and launch a flash command
through a series of peripheral bus writes.
The user cannot initiate any further flash commands until notified that the current
command has completed. The flash command structure and operation are detailed in
Flash Command Operations .
29.4.9 Flash Command Operations
Flash command operations are typically used to modify flash memory contents.
The next sections describe:
• The command write sequence used to set flash command parameters and launch
execution
• A description of all flash commands available
Functional Description
K22F Sub-Family Reference Manual, Rev. 4, 08/2016
652 NXP Semiconductors