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Application Note
© Motorola, Inc., 2001
AN2153
A Serial Bootloader for Reprogramming
the MC9S12DP256 FLASH Memory
By Gordon Doughman
Field Applications Engineer, Software Specialist
Dayton, Ohio
Introduction
The MC9S12DP256 is a member of the M68HC12 Family of 16-bit
microcontrollers (MCU) containing 262,144 bytes of bulk or sector
erasable, word programmable FLASH memory arranged as four
65,536 byte blocks. Including FLASH memory, rather than EPROM or
ROM, on a microcontroller has significant advantages.
For the manufacturer, placing system firmware in FLASH memory
provides several benefits. First, firmware development can be extended
late into the product development cycle by eliminating masked ROM
lead times. Second, when a manufacturer has several products based
on the same microcontroller, it can help eliminate inventory problems
and lead times associated with ROM-based microcontrollers. Finally, if
a severe bug is found in the product’s firmware during the manufacturing
process, the in-circuit reprogrammability of FLASH memory prevents the
manufacturer from having to scrap any work-in-process.
The ability of FLASH memory to be electrically erased and
reprogrammed also provides benefits for the manufacturer’s end
customers. The customer’s products can be updated or enhanced with
new features and capabilities without having to replace any components
or return a product to the factory.
Freescale Semiconductor, I
For More Information On This Product,
Go to: www.freescale.com
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© Freescale Semiconductor, Inc., 2004. All rights reserved.
