AN2153 Freescale Semiconductor / Motorola, AN2153 Datasheet - Page 21

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

Using
the S-Record
Bootloader
AN2153
MOTOROLA
The S-record bootloader presented in this application note utilizes the
on-chip SCI for communications with a host computer and does not
require any special programming software on the host.
The bootloader presented in this application note can be used to erase
and reprogram all but the upper 4 K of on-chip FLASH memory. The
bootloader program utilizes the on-chip SCI for communications and
does not require any special programming software on the host
computer. The only host software required is a simple terminal program
that is capable of communicating at 9600 to 115,200 baud and supports
XOn/XOff handshaking.
Invoking the bootloader causes the prompt shown in
displayed on the host terminal’s screen. The lowercase ASCII
characters a through c comprise the three valid bootloader commands.
These three lowercase characters were selected, rather than the ASCII
characters 1 through 3, to prevent accidental command execution. If a
problem occurs while programming the FLASH, an error message is
displayed, and the bootloader will redisplay its prompt and wait for a
command entry from the operator. Because the host computer will
continue sending the S-record file, each character of the S-record file
would be interpreted as an operator command entry. Since S-records
contain all of the ASCII numeric characters, it is highly likely that one of
them would be understood as a valid command.
pageNum = SRecLoadAddr / PPAGEWinSize;
PPAGEWinAddr = (SRecLoadAddr % PPAGEWinSize) + PPAGEWinStart;
Freescale Semiconductor, Inc.
Figure 11. PPAGE Number and Window Address Formulas
MC9S12DP256Bootloader
a) Erase Flash
b) Program Flash
c) Set Baud Rate
?
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Figure 12. Serial Bootloader Prompt
General FLASH Serial Bootloader Requirements
Figure 12
Application Note
to be
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