Mitsubishi Electric MELSEC-Q00U(J)CPU

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CHAPTER 2 APPLICATION OF PROGRAMMING
2
2.1 Memory and Files 2.1.1 Memory configuration and storable data
CHAPTER 2 APPLICATION OF PROGRAMMING
2.1 Memory and Files
2.1.1 Memory configuration and storable data
Memory configuration differs depending on the CPU module (refer to the following).
(1) Program memory
This memory stores programs and parameters required in processing of the CPU module.
(a) Processing a program
When a program is executed, data in the program memory are transferred to the program cache memory
*1
at
the following timings.
• Initial processing at power-on
• Initial processing at reset
*1 The program cache memory is used for program operations.
(b) Writing to the program memory
When a program is written to the program memory, it is temporarily written to the program cache memory, and
then automatically transferred back to the program memory.
While the CPU module is in the RUN status, automatic data transfer to the program memory can be disabled by setting.
( Page 173, Section 3.12.3)
CPU module Memory configuration
Q00UJCPU Program memory, standard ROM
Q00UCPU, Q01UCPU Program memory, standard RAM, standard ROM
Q02UCPU, QnUD(H)CPU, QnUDE(H)CPU
Program memory, standard RAM, standard ROM, memory card
(SRAM card, Flash card, or ATA card)
QnUDVCPU, QnUDPVCPU Program memory, standard RAM, standard ROM, SD memory card
<Drive 3>
Standard RAM
(SRAM)
<Drive 4>
Standard ROM
(flash ROM)
<Drive 0>
Program
memory
(flash ROM)
Inside CPU module
Programming tool
1) Data are written to the program
cache memory first.
2) After writing to the program
cache memory, the data are
automatically transferred to
the program memory.
Program
cache
memory
(SRAM)