Motorola M68HC11EVBU User Manual page 9

OPERATING INSTRUCTIONS
Table 4-1 is a lists of the BUFFALO monitor memory map limitations.
Address
$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. (Refer to the buf32.asm file on the EVBU diskette).
$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 to retain compatibility. (Refer to the
buf32.asm file on the EVBU diskette for additional information on DFLOP, TARGCO,
and HOSTCO).
Since the EVBU has no memory or peripherals located at $4000, these writes should
not concern most EVBU users.
$9800–$9801 BUFFALO supports serial I/O to a terminal via a ACIA (external IC) located at $9800 in
the memory map. During initialization, BUFFALO 3.2 reads and writes to location
$9800 and 9801 to see if a ACIA is present in the system. If a ACIA is installed on the
EVBU wire-wrap area and connected to the MCU, refer to the buf32.asm file on the
EVBU diskette to understand implications.
$D000–$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. If a DUART is
installed on the EVBU wire-wrap area and connected to the MCU, refer to the
buf32.asm file on the EVBU diskette.
4-2
Table 4-1. Monitor Memory Map Limitations
Restrictions
M68HC11EVBU/D