MC68HC908GR4MP datasheet(111/286 Pages) FREESCALE

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FLASH Mass Erase Operation

MC68HC908GR8 • MC68HC908GR4 Data Sheet, Rev. 7

Freescale Semiconductor

111

Wait for a time, tnvh (min. 5μs)

Clear the HVEN bit.

10.

After a time, trcv (typ. 1μs), the memory can be accessed again in read mode.

NOTE

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

unrelated operations may occur between the steps.

11.5 FLASH Mass Erase Operation

Use this step-by-step procedure to erase entire FLASH memory:

Set both the ERASE bit, and the MASS bit in the FLASH control register.

Read from the FLASH block protect register.

Write any data to any FLASH address(1) within the FLASH memory address range.

Wait for a time, tnvs (min. 10μs)

Set the HVEN bit.

Wait for a time, tMErase (min. 4ms)

Clear the ERASE and MASS bits.

NOTE

Mass erase is disabled whenever any block is protected (FLBPR does not

equal $FF).

Wait for a time, tnvhl (min. 100μs)

Clear the HVEN bit.

10.

After a time, trcv (typical 1μs), the memory can be accessed again in read mode.

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.

11.6 FLASH Program/Read 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, and $XXE0. During the

programming cycle, make sure that all addresses being written 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 11-2 is a flowchart representation):

NOTE

Only bytes which are currently $FF may be programmed.

1. When in Monitor mode, with security sequence failed see Chapter 15 Monitor ROM (MON), write to the FLASH block protect

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