AN2156 Freescale Semiconductor / Motorola, AN2156 Datasheet - Page 43

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

Question 12
Answer 12
Question 13
Answer 13
Question 14
Answer 14
Question 15
Answer 15
AN2156
MOTOROLA
I'm sending external data into the MC68HC908AS60A/AZ60A for
programming. How can I speed up this programming process?
Excluding data download time, it takes about two seconds to program
60 Kbytes of FLASH. If data is transferred at a higher communication
baud rate or in a parallel manner, the overall programming time can be
reduced. The ideal situation would be a fast parallel transfer of data
during the delay times associated with the programming algorithm.
If I program FLASH with 2-MHz bus frequency, can I read the FLASH
with 8-MHz bus frequency without any problems?
Yes. The FLASH will meet all specifications, including data retention
performance, if the FLASH is programmed/erased and used within
specification limits.
The program/erase operation is not successful in the monitor mode.
The FLASH memory is protected in the monitor mode to make it difficult
for unauthorized users to view the memory contents. Before
programming/erasing FLASH, the security feature on the part must be
“broken” to view the FLASH contents. When an attempt to break security
fails, the FLASH is not addressed during reads and invalid data will be
observed. Refer to the monitor ROM section, which describes how to
break security, in MC68HC908AZ60A and MC68HC908AS60A
Technical Data, Motorola document order number
MC68HC908AZ60A/D.
I have failed to break security in monitor mode. Can I execute a mass
erase to erase the security?
Yes. Mass erase is the only FLASH operation allowed after failing to
break security in monitor mode. When the mass erase operation is
executed, the address specified in step 3 of the sequence (refer to
FLASH Mass Erase
block protect register. Make sure the block protect feature is not
asserted or override it to mass erase the device.
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
Algorithm) must be the address of the FLASH
FLASH Frequently Asked Questions
Application Note
43