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7.3 Modifying MR100 Startup Program
MR100 comes with two types of startup programs as described below.
•
start.a30
This startup program is used when you created a program using the assembly language.
•
crt0mr.a30
This startup program is used when you created a program using the C language.
This program is derived from "start.a30" by adding an initialization routine in C language.
The startup programs perform the following:
•
Initialize the processor after a reset.
•
Initialize C language variables (crt0mr.a30 only).
•
Set the system timer.
•
Initialize MR100's data area.
Copy these startup programs from the directory indicated by environment variable "LIB100" to the current directory.
If necessary, correct or add the sections below:
•
Setting processor mode register
Set a processor mode matched to your system to the processor mode register. (58-60th line in crt0mr.a30)
•
Adding user-required initialization program
When there is an initialization program that is required for your application, add it to the 140th line in the C
language startup program (crt0mr.a30).
•
Enable the 138th – 139th line in the C language startup program (crt0mr.a30) if standard I/O function is
used.
