pwm_servos.h

P98v51RD2 source codes for all the peripherals

/*
 * Filename : pwm_servos.h
 * Hardware : Controller  -> P89V51RD2
 *            XTAL        -> 18.432 MHz
 *            Mode        -> 6 Clock/MC
 * I/O      : P1.4        -> Left  (PWM-CEX1)
 *            P1.5        -> Right (PWM-CEX2)
 * Compiler : SDCC
 * Author   : [e-mail]
 * Date		: 01/08/06
 */


/* Control the Left servo */
void ServoL_back()
{
    CCAP1H = 243;
}

void ServoL_forward()
{
    CCAP1H = 230;
}

void ServoL_stop()
{
    CCAP1H = 0;
}


/* Control the Right servo */
void ServoR_back()
{
    CCAP2H = 230;
}

void ServoR_forward()
{
    CCAP2H = 243;
}

void ServoR_stop()
{
    CCAP2H = 0;
}


/* Initialize the PCA and PWM mode */
void Servos_init()
{
/* Initial Timer0 Generate Overflow PCA */

    TMOD = 0x02;   /* Timer0 Mode2 : 8bit auto reload */
    TH0  = 16;     /* 256-240, 8.125usec Auto-relead (20msec/PWM) */
    TL0  = TH0;
    TCON = 0x10;   /* setb TR0, TCON or 0001,0000*/

/*
    Initial PWM Period  = 20mS (18.432MHz /6-Cycle Mode)
    Initial PCA Count From Timer0 Overflow
    1 Cycle of Timer0 = (1/18.432MHz)x6 = 0.326uS
    Timer0 AutoReload = 240 Cycle = 78.125uS
    1 Cycle PCA = [(1/18.432MHz)x6]x240 = 78.125uS
    Period 20mS of PCA = 20ms/78.125us = 256(CL Reload)
    CL(20mS) = 256 Cycle Auto Reload
    Load CCAPxH(1.0mS) = 256-13 = 243 (243,244,...,255 = 13 Cycle)
    Load CCAPxH(2.0mS) = 255-26 = 230 (230,231,...,255 = 26 Cycle)
*/
    CMOD=0x04;
    CCAPM1=0x42;
    CCAPM2=0x42;
    CCAP1H=0x00;
    CCAP2H=0x00;
    CCON=0x40;
}