Datasheet

MC68HC908QY4•MC68HC908QT4•MC68HC908QY2•MC68HC908QT2•MC68HC908QY1•MC68HC908QT1

48 FLASH Memory (FLASH) MOTOROLA

FLASH Memory (FLASH)

NON-DISCLOSURE AGREEMENT REQUIRED

4.5 FLASH Page Erase Operation

Use the following procedure to erase a page of FLASH memory. A page

consists of 64 consecutive bytes starting from addresses $XX00,

$XX40, $XX80, or $XXC0. The 48-byte user interrupt vectors area also

forms a page. Any FLASH memory page can be erased alone.

1. Set the ERASE bit and clear the MASS bit in the FLASH control

2. Read the FLASH block protect register.

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

the block to be erased.

4. Wait for a time, t

nvs

(minimum 10 µs).

5. Set the HVEN bit.

6. Wait for a time, t

Erase

(minimum 1 ms or 4 ms).

7. Clear the ERASE bit.

8. Wait for a time, t

nvh

(minimum 5 µs).

9. Clear the HVEN bit.

10. After time, t

rcv

(typical 1 µs),

the memory can be accessed in read

mode again.

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 as shown, but other unrelated operations

may occur between the steps.

In applications that need up to 10,000 program/erase cycles, use the

4 ms page erase specification to get improved long-term reliability. Any

application can use this 4 ms page erase specification. However, in

applications where a FLASH location will be erased and reprogrammed

less than 1000 times, and speed is important, use the 1 ms page erase

specification to get a lower minimum erase time.