main.c

程序代码如下：



//--------------------
//PWM测试程序
//--------------------
#include <p24Fxxxx.h>
_CONFIG3( WPFP_WPFP0 & SOSCSEL_IO & WUTSEL_LEG & WPDIS_WPDIS & WPCFG_WPCFGDIS & WPEND_WPENDMEM )
_CONFIG2( FNOSC_PRIPLL & POSCMOD_HS )//& PLL96MHZ_ON & PLLDIV_DIV5 )
//_CONFIG1( GCP_ON & JTAGEN_OFF & FWDTEN_OFF & ICS_PGx2 )

#if 1
/* INT is processor specific in length may vary in size */
typedef signed int          INT;
typedef signed char         INT8;
typedef signed short int    INT16;
typedef signed long int     INT32;

/* UINT is processor specific in length may vary in size */
typedef unsigned int        UINT;
typedef unsigned char       UINT8;
typedef unsigned short int  UINT16;
/* 24-bit type only available on C18 */
typedef unsigned long int   UINT32;     /* other name for 32-bit integer */
/* MPLAB C Compiler for PIC18 does not support 64-bit integers */
#endif
void oc1_inint(UINT16 PR2_num,UINT16 OC1R_num,UINT16 OC1RS_num);


void oc1_inint(UINT16 PR2_num,UINT16 OC1R_num,UINT16 OC1RS_num)
{
TRISBbits.TRISB13=0;
RPOR6bits.RP13R =18;// OC1_IO;  //RP15作为OC1输出

T2CON = 0;
TMR2 = 0;
//-----6,25kHZ----------
PR2 = PR2_num;//1060;
OC1R = OC1R_num;//530;
OC1RS = OC1RS_num;//530;
//----------------
OC1CON1 = 0x0006;  //PWM  
T2CON = (1 << 15)|(0 << 5)|(0 << 4); //启动时钟，1分频
IEC0 |= 0x0100;         //允许T2,中断

}
//-------------------------
//     main ()函数
//
//-------------------------
int main(void)
{

// Set up clock settings
CLKDIV    = 0x0000;
OSCCON    = 0x3302;   // Enable secondary oscillator, use HS oscillator
  TRISB = 0x0FFF;    //设置LED为输出RB15-RB12
  RPOR6bits.RP13R = 18;    //RP15作为OC1输出
  T2CON = (1 << 15)|(0 << 5)|(0 << 4);   //启动时钟，1分频
oc1_inint(1060,530,530);  //PWM 初始化,6,25kHZ
  while(1)
  {
;
  }

  return 0;  
}


我的程序，pwm出来的方波是6.25kHZ（160us）
但是和datasheet上面的方法，无法算出来这个值；


外部晶振20M
T2CON = (1 << 15)|(0 << 5)|(0 << 4); //启动时钟，1分频
TCY=TCY/2=(1000/20M)/2=25ns；


pwm周期=（PR2+1)*TCY*(Timer2预分频值)
pwm周期=1061*25ns*1
pwm周期=26.5us  
而实际是160us

请问是哪里的问题？


(原文件名:pwm.jpg)