Datasheet

Chapter 29 1024 KByte Flash Module (S12XFTM1024K5V2)

MC9S12XE-Family Reference Manual Rev. 1.25

Freescale Semiconductor 1179

29.4.2.4 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 29.4.2.7. 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 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 0 will return invalid data.

128

29.4.2.5 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 29-39. 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 29-40. Read Once Command Error Handling

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 29-30)

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 29-38. Erase Verify P-Flash Section Command Error Handling