AN2156 Freescale Semiconductor / Motorola, AN2156 Datasheet - Page 39

• Manufacturer Part Number: AN2156
• Description: Programming and Erasing FLASH and EEPROM Memories on the MC68HC908AS60A/AZ60A
• Manufacturer: Freescale Semiconductor / Motorola

FLASH Frequently Asked Questions
Question 1
Answer 1
AN2156
MOTOROLA
These questions and answers are designed to help the user with
frequent concerns.
I cannot program/erase FLASH memory at all. What should I consider to
make my program/erase code work?
Check the following:
•
•
•
•
Freescale Semiconductor, Inc.
For More Information On This Product,
Is each step of the programming algorithm (or erasing algorithm)
performed in the right order?
The sequence of the program and erase operations is interlocked
in hardware so only the prescribed order of these operations will
allow erase/program operations. However, other non-FLASH
operations may occur between the steps shown.
Is the memory block where you want to program/erase
unprotected?
The block protect feature of the FLASH is present to prevent
unintentional programming or erasing. The block protect bits must
be cleared such that the memory to be erased or programmed is
unprotected. The only way to override the block protection is to
apply voltage V
algorithms. (Refer to
the specification?
Timing is critical to ensure proper FLASH operation. Delay times
that are too long or too short can alter the FLASH performance to
the point where it does not work or is not reliable. Motorola does
not guarantee FLASH performance if all timing requirements are
not being adhered to.
Is the correct FLASH register being written to enable erase or
program?
The MC68HC908AS60A/AZ60A has two FLASH arrays with two
separate sets of control and block protect registers. Make sure the
appropriate register is being addressed. Refer to
Protection.
Are delay times such as t
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HI
on IRQ during the erase and program
FLASH Erase
PROG
, t
ERASE
FLASH Frequently Asked Questions
Operations.)
, t
MERASE
, t
FLASH Block
NVS
Application Note
, etc., within
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