NXP Semiconductors K22F series, Reference Manual, Page: 670 / 1407

29.4.11.8 Read 1s All Blocks Command
The Read 1s All Blocks command checks if the program flash blocks have been erased to
the specified read margin level, if applicable, and releases security if the readout passes,
i.e. all data reads as '1'.
Table 29-22. Read 1s All Blocks Command FCCOB Requirements
FCCOB Number FCCOB Contents [7:0]
0 0x40 (RD1ALL)
1 Read-1 Margin Choice
After clearing CCIF to launch the Read 1s All Blocks command, the flash memory
module :
• sets the read margin for 1s according to Table 29-23 ,
• checks the contents of the program flash are in the erased state.
If the flash memory module confirms that these memory resources are erased, access
control is disabled and security is released by setting the FSEC[SEC] field to the
unsecure state. The security byte in the flash configuration field (see
Flash Configuration
Field Description ) remains unaffected by the Read 1s All Blocks command. If the read
fails, i.e. all memory resources are not in the fully erased state, the FSTAT[MGSTAT0]
bit is set.
The CCIF flag sets after the Read 1s All Blocks operation has completed.
Table 29-23. Margin Level Choices for Read 1s All Blocks
Read Margin Choice Margin Level Description
0x00 Use the 'normal' read level for 1s
0x01 Apply the 'User' margin to the normal read-1 level
0x02 Apply the 'Factory' margin to the normal read-1 level
Table 29-24. Read 1s All Blocks Command Error Handling
Error Condition Error Bit
Command not available in current mode/security FSTAT[ACCERR]
An invalid margin choice is specified FSTAT[ACCERR]
Read-1s fails FSTAT[MGSTAT0]
Functional Description
K22F Sub-Family Reference Manual, Rev. 4, 08/2016
670 NXP Semiconductors