MC68HC908GP32_08 Datasheet, PDF(41/266 Page) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

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MC68HC908GP32_08 Datasheet, PDF (41/266 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

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FLASH Memory

During the programming cycle, make sure that all addresses being written to fit within one of the ranges

specified above. Attempts to program addresses in different row ranges in one programming cycle will

fail. Use this step-by-step procedure to program a row of FLASH memory (Figure 2-4 is a flowchart

representation).

NOTE

Only bytes which are currently $FF may be programmed.

1. Set the PGM bit. This configures the memory for program operation and enables the latching of

address and data for programming.

2. Read from the FLASH block protect register.

3. Write any data to any FLASH address within the row address range desired.

4. Wait for a time, tnvs (min. 10 Âµs).

5. Set the HVEN bit.

6. Wait for a time, tpgs (min. 5 Âµs).

7. Write data to the FLASH address to be programmed. (See note.)

8. Wait for a time, tPROG (min. 30 Âµs).

9. Repeat step 7 and 8 until all the bytes within the row are programmed.

10. Clear the PGM bit. (See note.)

11. Wait for a time, tnvh (min. 5 Âµs).

12. Clear the HVEN bit.

13. After time, tRCV (typical 1 Âµs), the memory can be accessed in read mode again.

This program sequence is repeated throughout the memory until all data is programmed.

NOTE

Programming and erasing of FLASH locations can not be performed by

code being executed from the same FLASH array.

NOTE

While these operations must be performed in the order shown, other

unrelated operations may occur between the steps. Care must be taken

within the FLASH array memory space such as the COP control register

(COPCTL) at $FFFF.

NOTE

It is highly recommended that interrupts be disabled during program/ erase

operations.

NOTE

Do not exceed tPROG maximum or tHV maximum. tHV is defined as the

cumulative high voltage programming time to the same row before next

erase. tHV must satisfy this condition:

tNVS + tNVH + tPGS + (tPROG x 64) â¤ tHV maximum

Refer to 19.17 Memory Characteristics.

NOTE

The time between programming the FLASH address change (step 7 to

step 7), or the time between the last FLASH programmed to clearing the

MC68HC908GP32 Data Sheet, Rev. 10

Freescale Semiconductor

41

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