Datasheet

Chapter 4 Memory

MC9S08JM60 Series Data Sheet, Rev. 3

Freescale Semiconductor 63

4.7.6 Flash Command Register (FCMD)

Only five command codes are recognized in normal user modes as shown in Table 4-14. Refer to

Section 4.5.3, “Program and Erase Command Execution,” for a detailed discussion of flash programming

and erase operations.

All other command codes are illegal and generate an access error.

FACCERR

Access Error Flag — FACCERR is set automatically when the proper command sequence is not obeyed exactly

(the erroneous command is ignored), if a program or erase operation is attempted before the FCDIV register has

been initialized, or if the MCU enters stop while a command was in progress. For a more detailed discussion of

the exact actions that are considered access errors, see Section 4.5.5, “Access Errors.” FACCERR is cleared by

writing a 1 to FACCERR. Writing a 0 to FACCERR has no meaning or effect.

0 No access error.

1 An access error has occurred.

FBLANK

Flash Verified as All Blank (erased) Flag — FBLANK is set automatically at the conclusion of a blank check

command if the entire flash array was verified to be erased. FBLANK is cleared by clearing FCBEF to write a new

valid command. Writing to FBLANK has no meaning or effect.

0 After a blank check command is completed and FCCF = 1, FBLANK = 0 indicates the flash array is not

completely erased.

1 After a blank check command is completed and FCCF = 1, FBLANK = 1 indicates the flash array is completely

erased (all 0xFF).

76543210

R00000000

W FCMD7 FCMD6 FCMD5 FCMD4 FCMD3 FCMD2 FCMD1 FCMD0

Reset00000000

Figure 4-10. Flash Command Register (FCMD)

Table 4-13. FCMD Register Field Descriptions

Field Description

FCMD[7:0] Flash Command Bits — See Ta bl e 4 -1 4

Table 4-14. Flash Commands

Command FCMD Equate File Label

Blank check 0x05 mBlank

Byte program 0x20 mByteProg

Byte program — burst mode 0x25 mBurstProg

Page erase (512 bytes/page) 0x40 mPageErase

Mass erase (all flash) 0x41 mMassErase

Table 4-12. FSTAT Register Field Descriptions (continued)

Field Description