MC68HC711xxxx Motorola, MC68HC711xxxx Datasheet - Page 248

• Manufacturer Part Number: MC68HC711xxxx
• Description: Microcontrollers
• Manufacturer: Motorola

Application Note
Boot ROM Variations
Commented Boot ROM Listing
248
Different versions of the M68HC11 have different versions of the
bootstrap ROM program.
ROMs in 16 members of the M68HC11 Family.
The boot ROMs for the MC68HC11F1, the MC68HC711K4, and the
MC68HC11K4 allow additional choices of baud rates for bootloader
communications. For the three new baud rates, the first character used
to determine the baud rate is not $FF as it was in earlier M68HC11s. The
intercharacter delay that terminates the variable-length download is also
different for these new baud rates.
characters, delay times, and baud rates as they relate to E-clock
frequency.
Listing 3. MC68HC711E9 Bootloader ROM
commented listing of the boot ROM program in the MC68HC711E9
version of the M68HC11. Other versions can be found in Appendix B of
the M68HC11 Reference Manual and in the freeware area of the
Motorola Web site.
Character
Sync
$FD
$FD
$FF
$FF
$F0
17.3 characters 5208
4.9 characters
13 characters
4 characters
4 characters
Timeout
Delay
Table 3. Bootloader Baud Rates
2 MHz 2.1 MHz 3 MHz 3.15 MHz 4 MHz 4.2 MHz
Table 3
7812
1200
9600
3906
10,080 14,400
8192
1260
5461
4096
summarizes the features of the boot
Table 3
Baud Rates at E Clock =
11,718
1800
7812
5859
shows the synchronization
contains a complete
12,288
15,120
1890
8192
6144
AN1060 — Rev. 1.0
15,624
19,200
10,416
2400
7812
MOTOROLA
16,838
20,160
10,922
2520
8192