Writing cyclic handler/alarm handler, 4 writing cyclic handler/alarm handler – Renesas 70 User Manual

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Chapter 5 Detailed Applications

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5.2.4

Writing Cyclic Handler/Alarm Handler

When describing the cyclic or alarm handler in Assembly Language, observe the following precautions.

1. At the beginning of file, be sure to include "mr308.inc" which is in the system directory.

2. For the symbol indicating the handler start address, make the external declaration.

3. Always use the RTS instruction (subroutine return instruction) to return from cyclic han-

dlers and alarm handlers.

For examples:

.INCLUDE mr308.inc

-----

(1)

.GLB

cychand

-----

(2)

cychand:

; handler process

rts

-----

(3)

Figure 5.10 Example Handler Written in Assembly Language

Use the .GLB pseudo-directive.