Flash Memory
MPC5566 Microcontroller Reference Manual, Rev. 2
Freescale Semiconductor 13-27
Whenever a program operation occurs, ECC bits are programmed. ECC is handled on a 64-bit boundary.
Thus, if only 1 word in any given 64-bit ECC segment is programmed, do not program the adjoining word
(in that segment) because the ECC calculation has already completed for that 64-bit segment. Attempts to
program the adjoining word results in an operation failure. All programming operations must be from 64
bits to 256 bits, and be 64-bit aligned. The programming operation must completely fill the selected ECC
segments within the page.
The program operation consists of the following sequence of events:
1. Change the value in the FLASH_MCR[PGM] bit from a 0 to a 1.
NOTE
Ensure the block that contains the address to be programmed is unlocked.
Refer to Section 13.3.2.2, “Low/Mid Address Space Block Locking
Register (FLASH_LMLR), Section 13.3.2.3, “High Address Space Block
Locking Register (FLASH_HLR)” and Section 13.3.2.4, “Secondary
Low/Mid Address Space Block Locking Register (FLASH_SLMLR)” for
more information.
2. Write the first address to be programmed in the flash module with the program data. This write is
referred to as a program data interlock write. An interlock write can either be an aligned-word or
doubleword.
3. If more than 1 word or doubleword is to be programmed, write each additional address in the page
with data to be programmed. This is referred to as a program data write. All unwritten data words
default to 0xFFFF FFFF.
4. Write a logic 1 to the FLASH_MCR[EHV] bit to start the internal program sequence or skip to step
9 to terminate.
5. Wait until the FLASH_MCR[DONE] bit goes high.
6. Confirm FLASH_MCR[PEG] = 1.
7. Write a logic 0 to the FLASH_MCR[EHV] bit.
8. If more addresses are to be programmed, return to step 2.
9. Write a logic 0 to the FLASH_MCR[PGM] bit to terminate the program sequence.
The program sequence is presented graphically in Figure 13-14. The program suspend operation detailed
in Figure 13-14 is discussed in Section 13.4.2.3.2, “Flash Program Suspend/Resume.”
The first write after a program is initiated determines the page address to be programmed. The program
can be initiated with the 0 to 1 transition of the FLASH_MCR[PGM] bit or by clearing the
FLASH_MCR[EHV] bit at the end of a previous program. This first write is referred to as an interlock
write. If the program is not an erase-suspended program, the interlock write determines if the shadow or
normal array space is programmed and causes FLASH_MCR[PEAS] to be set/cleared.
In the case of an erase-suspended program, the value in FLASH_MCR[PEAS], is retained from the erase.
An interlock write must be performed before setting FLASH_MCR[EHV]. The user can terminate a
program sequence by clearing FLASH_MCR[PGM] prior to setting FLASH_MCR[EHV].
If multiple writes are done to the same location the data for the last write is used in programming.
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