1. Sound effects with Rotation control
Prateek Jain
May 2,2009
Microcomputer Systems I
Dr. Kepuska

2. Overview Purpose Audio Generation Code Demo Talkthrough.h Main.c
Initialize.c
ISR.c
Process_data.c
Demo

3. Purpose
Press PF8 once: rotation of sound is heard in anti-clock wise direction.
Press PF8 twice: rotation of sound is heard in clock wise direction.
Press PF9: echo effect is heard and when pressed again its off.
Press PF10: Bouncy effect is heard and when pressed again its off.

4. Talkthrough.h …//Surround Sound void Surround_Snd(void);
extern int SkipPosition;
extern int check;
extern int checkleft;
extern int checkright;
extern int echosound; extern int bouncysound;
void LeftSurround(void);
void RightSurround(void);
void echoeffect(void);
void bounceeffect(void);

5. Main.c …int SkipPosition = 0; int bouncysound=0; int check = 0;
int echosound=0;
int checkleft=0;
int checkright=0;

6. Initialize.c … void Init_Interrupts(void) {
// Set System Interrupt Assignment Registers
//2 for Sport0 RX, 5 for Flag A, and 4 for Timer0
*pSIC_IAR0 = 0xffffffff;
*pSIC_IAR1 = 0xffffff2f;
*pSIC_IAR2 = 0xffff5ff4;
// assign ISRs to interrupt vectors
register_handler(ik_ivg9, Sport0_RX_ISR);
register_handler(ik_ivg12, FlagA_ISR);
register_handler(ik_ivg11, Timer0_ISR);
// enable interrupts Timer0, Sport0 RX, and Flag A
*pSIC_IMASK = 0x ; }

7. Initialize.c (cont’d) … void Init_Flags(void) {
*pFIO_INEN = 0x0700; //need PF8, PF9, and PF10
*pFIO_DIR = 0x0000;
*pFIO_EDGE = 0x0700;
*pFIO_MASKA_D = 0x0700; }
void Init_Timers(void)
*pTIMER0_CONFIG =0x0019;
*pTIMER0_PERIOD =0x ;
*pTIMER0_WIDTH =0x ;
*pTIMER_ENABLE =0x0001;

8. Process_data.c void echoeffect(void)
{static short echoBufferL[4000],echoBufferR[4000];
int left, right;
static int i = 0;
echoBufferL[i] = (short)(iChannel0LeftIn>>8) + (echoBufferL[i]/2);
echoBufferR[i] = (short)(iChannel0RightIn>>8) + (echoBufferR[i]/2);
left = echoBufferL[i];
right = echoBufferR[i]; I
Channel0LeftOut = left << 8;
iChannel0RightOut = right << 8;
if(i>=4000-1)
i = 0;
else i++; }

9. Demo

10. Questions?