MC908QL4ME View Datasheet(PDF) - Freescale Semiconductor

Part Name

Description

Manufacturer

MC908QL4ME

M68HC08 Microcontrollers

Freescale Semiconductor 

Memory

2.6.4 FLASH Program Operation

Programming of the FLASH memory is done on a row basis. A row consists of 32 consecutive bytes

starting from addresses $XX00, $XX20, $XX40, $XX60, $XX80, $XXA0, $XXC0, or $XXE0. Use the

following step-by-step procedure to program a row of FLASH memory

Figure 2-4 shows a flowchart of the programming algorithm.

NOTE

Do not program any byte in the FLASH more than once after a successful

erase operation. Reprogramming bits to a byte which is already

programmed is not allowed without first erasing the page in which the byte

resides or mass erasing the entire FLASH memory. Programming without

first erasing may disturb data stored in the FLASH.

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

address and data for programming.

2. Read the FLASH block protect register.

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

4. Wait for a time, tNVS.

5. Set the HVEN bit.

6. Wait for a time, tPGS.

7. Write data to the FLASH address being programmed(1).

8. Wait for time, tPROG.

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

10. Clear the PGM bit (1).

11. Wait for time, tNVH.

12. Clear the HVEN bit.

13. After time, tRCV, the memory can be accessed in read mode again.

NOTE

The COP register at location $FFFF should not be written between steps

5-12, when the HVEN bit is set. Since this register is located at a valid

FLASH address, unpredictable behavior may occur if this location is written

while HVEN is set.

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

NOTE

Programming and erasing of FLASH locations cannot be performed by

code being executed from the FLASH memory. While these operations

must be performed in the order shown, other unrelated operations may

occur between the steps. Do not exceed tPROG maximum, see 17.15

Memory Characteristics.

1. The time between each FLASH address change, or the time between the last FLASH address programmed to clearing

PGM bit, must not exceed the maximum programming time, tPROG maximum.

MC68HC908QL4 Data Sheet, Rev. 7

38

Freescale Semiconductor

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