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Chapter 9 512 KByte Flash Module (S12XFTM512K3V1)
MC9S12XF - Family Reference Manual, Rev.1.19
320
Freescale Semiconductor
9.4.2.4
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 block 0. The Read Once field is programmed using the
Program Once command described in
Section 9.4.2.7. 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 ag 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 0 will return invalid data.
128
9.4.2.5
Load Data Field Command
The Load Data Field command is executed to provide FCCOB parameters for multiple P-Flash blocks for
a future simultaneous program operation in the P-Flash memory space.
FERSTAT
EPVIOLIF
None
Table 9-39. Read Once Command FCCOB Requirements
CCOBIX[2:0]
FCCOB Parameters
000
0x04
Not Required
001
Read Once phrase index (0x0000 - 0x0007)
010
Read Once word 0 value
011
Read Once word 1 value
100
Read Once word 2 value
101
Read Once word 3 value
Table 9-40. Read Once Command Error Handling
Register
Error Bit
Error Condition
FSTAT
ACCERR
Set if CCOBIX[2:0] != 001 at command launch
Set if a Load Data Field command sequence is currently active
Set if command not available in current mode (see
Table 9-30)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
FERSTAT
EPVIOLIF
None
Table 9-38. Erase Verify P-Flash Section Command Error Handling
Register
Error Bit
Error Condition