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Renesas Electronics Europe - Knowledgebase

What does ""W4301: Can't initialize RAM area 'ffe20h - ffe27h'"" means?

Latest Updated:11/25/2014


The assembler of the RL78/78K0R compiler package (CA78K0R) is producing the following warning message.
W4301: Can't initialize RAM area 'ffe20h - ffe27h'


The warning message above indicates that there are statements to specify initial values for the RAM area (in this example, the area from FFE20H to FFE27H).
This can be for either of the two reasons below.

  1. Program code or a const constant is intentionally being assigned to RAM.
  2. Program code or a const constant is unintentionally being assigned to RAM.

Responses in case of the respective reasons are described below.

  1. When a program or a const constant is assigned to RAM, the program must be ROMization processor.
    (For details, refer to the user's manual here.)
  2. Check whether or not initial values for the data segment (DSEG) have been set by using the DB or DW directive.

    The DB and DW directives are used to secure part of the ROM area and to set initial values in that part. They are not allowed to specify any part of the RAM area.

    Use the DS directive to set initial values in the RAM area. Place a DS directive in DSEG to secure part of the RAM area, and then use the DB or DW directive to store the initial values or include instructions required for setting initial values (e.g., MOV) in the code segment (CSEG).
Suitable Products
CS+ (formerly CubeSuite+)
C Compiler Package for RL78 and 78K Families
Compiler for RL78 Family and 78K0R [CA78K0R]