Motorola M68HC11EVB, Руководство пользователя

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OPERATING INSTRUCTIONS
4-2 M68HC11EVB/D
The EVB allows the user to use all the features of the BUFFALO evaluation software, however it
should be noted (when designing code) that the BUFFALO uses the MCU on-chip RAM
locations $0048-$00FF leaving only 72 bytes for the user (i.e., $0000-$0047).
The user must be aware of the BUFFALO monitor address location restrictions. Table 4-1 lists
the monitor memory map limitations.
Table 4-1. Monitor Memory Map Limitations
Address Restrictions
$0000-$0047 Available to user. (BUFFALO sets default value of the user stack
pointer at location $0047.)
$0048-$0065 BUFFALO monitor stack area.
$0066-$00C3 BUFFALO variables.
$00C4-$00FF Interrupt pseudo vectors (jumps).
$0100-$01FF User available.
$1000-$103F MCU control registers. Although RAM and registers can be moved in
the memory map, BUFFALO expects RAM at $0000 (actually requires
$0048-$00FF) and registers at $1000-$103F.
$4000 Some versions of EVBs have a D flip-flop addressed at this location.
During initialization, BUFFALO 3.2 writes $00 to location $4000 and
various monitor operations cause $00 or $01 to be written to $4000.
(Refer to the buf25.asm file on the EVB diskette for the definitions of
DFLOP, TARGCO, and HOSTCO for additional information).
Since the EVB has no memory or peripherals located at $4000, these
writes should not concern most EVB users.
$D000-$D00F BUFFALO supports serial I/O to a terminal and/or host via a DUART
(external IC) located at $D000 in the memory map. During
initialization, BUFFALO 3.2 reads and writes to location $D00C to see
if a DUART is present in the system. Refer to the buf25.asm file on
the EVB diskette.