Renesas M16C/26A Bedienungsanleitung PDF herunterladen (Seite 8)

M16C/2

Using the M16C/26 Timers in Timer Mod

REU05B0046-0100Z June 2003

Page 8 of 8

/*****************************************************************************

Name: init()

Parameters: none

Returns: nothing

Description: Timer TA0 is setup to interrupt every 1ms.

**************************************************************************** */

void init()

{

ta0 = 2500; // 20MHz xtal divide by 8 at 1ms intervals = 2,500 counts

/* the following procedure for writing an Interrupt Priority Level follows what

is described in the M16C datasheets under 'Interrupts'. */

_asm (" fclr i") ; //turn off interrupts before modifying IPL

ta0ic |= CNTR_IPL; // use read-modify-write instruction to write IPL

ta0mr = TIME_CONFIG;

_asm (" fset i");

ta0s = 1; //start counting

}

In order for this program to run properly, timer A0’s interrupt vector needs to point to the TimerA0Int function. The

interrupt vector table is near the end of the startup file “sect30.inc”. Insert the function label “_TimerA0Int” into

the interrupt vector table at vector 21 as shown below.

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;

; File Name: sect30.inc

;

; Content: Section include file for MSV30262-SKP.

;

;=============================================================================

; $Log:$

;=============================================================================

.lword dummy_int ; uart1 transmit(for user)(vector 19)

.lword dummy_int ; uart1 receive(for user)(vector 20)

.glb _TimerA0Int

.lword _TimerA0Int ; timer A0(for user)(vector 21)

.lword dummy_int ; timer A1(for user)(vector 22)

.lword dummy_int ; timer A2(for user)(vector 23)

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Renesas M16C/26A Bedienungsanleitung Seite 8