Freescale Semiconductor MC9S12ZVM series, Reference Manual

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Chapter 19 128 KB Flash Module (S12ZFTMRZ128K512V2)
MC9S12ZVM Family Reference Manual Rev. 1.3
Freescale Semiconductor 723
19.4.7.4 Read Once Command
The Read Once command provides read access to a reserved 64 byte field (8 phrases) located in the
nonvolatile information register of P-Flash. The Read Once field is programmed using the Program Once
command described in
Section 19.4.7.6 . The Read Once command must not be executed from the Flash
block containing the Program Once reserved field to avoid code runaway.
Upon clearing CCIF to launch the Read Once command, a Read Once phrase is fetched and stored in the
FCCOB indexed register. The CCIF flag will set after the Read Once operation has completed. Valid
phrase index values for the Read Once command range from 0x0000 to 0x0007. During execution of the
Read Once command, any attempt to read addresses within P-Flash block will return invalid data.
8
19.4.7.5 Program P-Flash Command
The Program P-Flash operation will program a previously erased phrase in the P-Flash memory using an
embedded algorithm.
CAUTION
A P-Flash phrase must be in the erased state before being programmed.
Cumulative programming of bits within a Flash phrase is not allowed.
Table 19-39. Read Once Command FCCOB Requirements
Register FCCOB Parameters
FCCOB0 0x04 Not Required
FCCOB1 Read Once phrase index (0x0000 - 0x0007)
FCCOB2 Read Once word 0 value
FCCOB3 Read Once word 1 value
FCCOB4 Read Once word 2 value
FCCOB5 Read Once word 3 value
Table 19-40. Read Once Command Error Handling
Register Error Bit Error Condition
FSTAT
ACCERR
Set if CCOBIX[2:0] != 001 at command launch
Set if command not available in current mode (see Table 19-29 )
Set if an invalid phrase index is supplied
FPVIOL None
MGSTAT1 Set if any errors have been encountered during the read
MGSTAT0 Set if any non-correctable errors have been encountered during the read