Memory Map; Data Memory Area Address Configuration - Mitsubishi MELSEC-A Series Programming Manual

8. MICROCOMPUTER MODE

8.3.1 Memory map

8.3.2 Data memory area address configuration

POINTS
(1) The processing time of a microcomputer program called by one SUB
instruction must be 5 msec or less. If it exceeds 5 msec, operation
combination between the microcomputer program processing and the
internal processing of the PC becomes out of control and the PC cannot
run correctly.
(2) If a microcomputer program which needs more than 5 msec for processing
is to be executed, divide it into several blocks which are called
consecutively. This method can shorten the processing time of a
microcomputer program called by one SUB instruction.
The microcomputer program may be used in the following areas.
0
8000H
Data memory area
9FFFH
A100H
Work area for
Microcomputer program
A1FFH
Fig. 8.4 Data Memory and Work Areas
One address of the data memory area consists of 16 bits which are further divided
into the odd and even areas (8 bits respectively).
1 address
8000H
Fig. 8.5 Configuration of 1 Address (16 bits)
8K bytes
256K bytes
16 bits
Odd 8-bit area
(8001H)
8 − 6
MELSEC-A
For details, refer to Section 8.3.3.
Odd 8-bit area
(8001H)