Freescale Semiconductor Demonstration Board for Freescale MC9S12XHY256 Microcontroller DEMO9S12XHY256 DEMO9S12XHY256 Manual De Usuario

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MC9S12XHY-Family Reference Manual, Rev. 1.04
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Freescale Semiconductor
19.4.2.6
Program Once Command
The Program Once command restricts programming to a reserved 64 byte field (8 phrases) in the
nonvolatile information register located in P-Flash block 0. The Program Once reserved field can be read
using the Read Once command as described in
. The Program Once command must only
be issued once since the nonvolatile information register in P-Flash block 0 cannot be erased. The Program
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 Program Once command, the Memory Controller first verifies that the
selected phrase is erased. If erased, then the selected phrase will be programmed and then verified with
read back. The CCIF flag will remain clear, setting only after the Program Once operation has completed.
The reserved nonvolatile information register accessed by the Program Once command cannot be erased
and any attempt to program one of these phrases a second time will not be allowed. Valid phrase index
values for the Program Once command range from 0x0000 to 0x0007. During execution of the Program
Once command, any attempt to read addresses within P-Flash block 0 will return invalid data.
Table 19-39. Program P-Flash Command Error Handling
Register
Error Bit
Error Condition
FSTAT
ACCERR
Set if CCOBIX[2:0] != 101 at command launch
Set if command not available in current mode (see
)
Set if an invalid global address [22:0] is supplied
Set if a misaligned phrase address is supplied (global address [2:0] != 000)
FPVIOL
Set if the global address [22:0] points to a protected area
MGSTAT1
Set if any errors have been encountered during the verify operation
MGSTAT0
Set if any non-correctable errors have been encountered during the verify
operation
Table 19-40. Program Once Command FCCOB Requirements
CCOBIX[2:0]
FCCOB Parameters
000
0x07
Not Required
001
Program Once phrase index (0x0000 - 0x0007)
010
Program Once word 0 value
011
Program Once word 1 value
100
Program Once word 2 value
101
Program Once word 3 value