Freescale Semiconductor, Inc.
Monitor Read-Only Memory (MON)
10.4.5 Commands
The monitor ROM uses these commands:
•
•
•
•
•
•
READ, read memory
WRITE, write memory
IREAD, indexed read
IWRITE, indexed write
READSP, read stack pointer
RUN, run user program
A sequence of IREAD or IWRITE commands can access a block of
memory sequentially over the full 64-Kbyte memory map.
Table 10-3. READ (Read Memory) Command
Description
Operand
Read byte from memory
Specifies 2-byte address in high byte:low byte order
Returns contents of specified address
$4A
Data Returned
Opcode
Command Sequence
SENT TO
MONITOR
READ
READ
ADDR. HIGH
ADDR. HIGH
ADDR. LOW
ADDR. LOW
DATA
1
3
1
3
1
2
ECHO
RESULT
Notes: 1 = Echo delay (2 bit times)
2 = Data return delay (2 bit times)
3 = Wait 1 bit time before sending next byte.
Advance Information
156
MC68HC908RFRK2
MOTOROLA
Monitor Read-Only Memory (MON)
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