AN2153 Freescale Semiconductor / Motorola, AN2153 Datasheet - Page 19

• Manufacturer Part Number: AN2153
• Description: A Serial Bootloader for Reprogramming the MC9S12DP256 FLASH Memory
• Manufacturer: Freescale Semiconductor / Motorola

AN2153
MOTOROLA
NOTE:
that S2 records would provide the necessary load address information
required for M68HC12 object files. However, as those who are familiar
with the M68000 Family know, the M68000 has a linear (non-paged)
address space. Thus, development tools, such as non-volatile memory
device programmers, interpret the 24-bit address as a simple linear
address when placing program data into memory devices.
Because the M68HC12 memory space expansion is based on 16-Kbyte
pages, there is not a direct one-to-one mapping of the 24-bit linear
address contained in the S2 record to the 16-Kbyte program memory
expansion space. Instead of defining a new S-record type or utilizing an
existing S-record type in a non-standard manner, the bootloader’s
program FLASH command views the MC9S12DP256’s memory space
as a simple linear array of memory that begins at an address of $C0000.
This is the same format in which S-records would need to be presented
to a stand alone non-volatile memory device programmer.
The MC9S12DP256 implements six bits of the PPAGE register which
gives it a 1MB program memory address space that is accessed through
the PPAGE window at addresses $8000–$BFFF. The lower 768-K
portion of the address space, accessed with PPAGE values $00–$2F,
are reserved for external memory when the part is operated in expanded
mode. The upper 256 K of the address space, accessed with PPAGE
values $30–$3F, is occupied by the on-chip FLASH memory. The
mapping between the linear address contained in the S-record and the
16-Kbyte page viewable through the PPAGE is shown in
The generation of S-records that meet these requirements is the
responsibility of the linker and/or S-record generation utility provided by
the compiler/assembler vendor. Cosmic Software’s linker and S-record
generation utility is capable of producing properly formatted S-records
that can be used by the bootloader. Other vendor’s tools may or may not
posses this capability. For those compilers and assemblers that produce
“banked” S-records, an S-record conversion utility, SRecCvt.exe, is
available on the Web that can be used to convert “banked” S-records to
the linear S-record format required by the serial bootloader.
The bootloader is limited to receiving S-records containing a maximum
of 64 bytes in the code/data field. If an S-record containing more than
64 bytes in the code/data field is received, an error message will be
displayed.
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
General FLASH Serial Bootloader Requirements
Figure
Application Note
10.
19