Command Table; Interrupt Vectors; Interrupt Vector Jump Table - Motorola M68HC11EVBU User Manual

3.2.5

Command Table

The command table consists of three lines for each entry. The first byte is the number of
characters in the command name. The second entry is the ASCII command name. The third entry
is the starting address of the command module. As an example:
FCB 3
FCC 'ASM'
FDB ASM
Each command in the BUFFALO program is a individual module. Thus, to add or delete
commands, all that is required is to include a new command module or delete an existing module
and/or delete the entry in the command table. This procedure may be difficult to accomplish with
the M68HC11EVBU because the BUFFALO monitor is contained in ROM. However with the
standard M68HC11EVB, you may change commands, as this version of the BUFFALO monitor
is contained in EPROM.
3.3

INTERRUPT VECTORS

Interrupt vectors residing in MCU internal ROM are accessible as follows. Each vector is
assigned a three byte field residing in EVBU memory map locations $0000-$00FF. This is where
the monitor program expects the MCU RAM to reside. Each vector points to a three byte field
which is used as a jump table to the vector service routine. Table 3-2 lists the interrupt vectors
and associated three byte field.
Serial Communications Interface (SCI)
Serial Peripheral Interface (SPI)
Pulse Accumulator Input Edge
Pulse Accumulator Overflow
Timer Overflow
Timer Output Compare 5
Timer Output Compare 4
Timer Output Compare 3
Timer Output Compare 2
Timer Output Compare 1
M68HC11EVBU/D
3 characters in command name
ASCII literal command name string
Jump address for command module
Table 3-2. Interrupt Vector Jump Table
Interrupt Vector
MONITOR PROGRAM
Field
$E0C4 – $E0C6
$E0C7 – $E0C9
$E0CA – $E0CC
$E0CD – $E0CF
$E0D0 – $E0D2
$E0D3 – $E0D5
$E0D6 – $E0D8
$E0D9 – $E0DB
$E0DC – $E0DE
$E0DF – $E0E1
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