PIC (dsPIC33EP 512MU810) : High Speed PWM module - embedded

Question

I'm trying to generate a 10% duty cycle-1kHz PWM with a clock at 80Mhz (F_osc) using the inbuilt (Hardware) high speed PWM.
According to the documentation,
Base Period (number for the PTPER) is calculated by
PTPER = F_osc / [(F_pwm) x (PWM_Clk_Prescale)]
Substituting F_osc = 80Mhz, F_pwm = 1khz and Prescale = 8, I'm getting a count of PTPER=10,000.
However, from my output on an oscilloscope, I can see that I have PWM frequency of ~2khz..
Am I doing anything wrong? Below is my code --
#include<p33EP512MU810.h>
#include<p33Exxxx.h>
//---------------- compiler directives------------------
_FOSCSEL(FNOSC_FRC);
_FOSC(FCKSM_CSECMD & OSCIOFNC_OFF & POSCMD_XT); // Clock Switching Enabled and Fail Safe Clock Monitor is disabled
// OSC2 Pin Function: OSC2 is Clock Output
// Primary Oscillator Mode: XT Crystal
_FWDT(FWDTEN_OFF); // Watchdog Timer Enabled/disabled by user software
//------------------------------------------------------
//function to initialise oscillator and set up clock
void Init_Oscillator(void)
{
// Configure Oscillator to operate the device at 40Mhz
// Fosc= Fin*M/(N1*N2), Fcy=Fosc/2
// Fosc= 12M*40/(3*2)=80Mhz for 12M input clock
// 0.5M < Fin/N1 < 8MHz
// 100M < Fin*M/N2 < 200M
// Fcy = Fosc / 2 = 40 MIPS
PLLFBD = 38; // M=80
CLKDIVbits.PLLPOST = 0; // N2=2
CLKDIVbits.PLLPRE = 1; // N1=3
OSCTUN = 0; // Tune FRC oscillator, if FRC is used
RCONbits.SWDTEN=0; // Disable Watch Dog Timer
// Clock switch to incorporate PLL
__builtin_write_OSCCONH(0x03); // Initiate Clock Switch to
// Primary Oscillator with PLL (NOSC=0b011)
__builtin_write_OSCCONL(0x01); // Start clock switching
while (OSCCONbits.COSC != 0b011); // Wait for Clock switch (to XT w/ PLL) to occur
while(OSCCONbits.LOCK!=1) {}; // Wait for PLL to lock
}
void Init_PWM(void)
{
/**** PTCON: PWM Time Base Control Register ****/
PTCONbits.PTEN = 0; // Timer Enable bit: DISABLE MCPWM
//---------------------------------------------------------------
//Prescaler 1:8
PTCON2bits.PCLKDIV = 0b011; // PCLKSEL: 1,2,4,8,16,32,64
//mode selection
PWMCON1 = 0x0000; //PTPER holds period count of PWM
//Independent mode enable
IOCON1 = 0xCC00; //fig 14-35 of PWM manual
// 0xCC00 => PENH high, PENL high, PMOD: 11- True Independent PWM o/p
//---------------------------------------------------------------
/**** PTPER: PWM Time Base Period Register ****/
PTPER = 10000; // Period Value bits
//Enable PWM timer
PTCONbits.PTEN = 1; // Timer Enable bit: ENABLE MCPWM
}
//--- extra settings:
// 1) Stop in IDLE MODE :: PTCONbits.PTSIDL = 1 (yes)
// 2) Setting a particular pin as output ==> IOCONxbits.PENH(/L) = 1(enabled)
// 3) MDC,PDC,SDC et al depend on the PWM MODE.
// Resp, selection of PTPER,PHASE,SPHASE.
//---
int main(void)
{
Init_Oscillator();
Init_PWM();// Initialize PWM module
PDC1 = 1000; // This sets the duty cycle.
while(1); //loop forever //while
return 0;
}

Answer 1

Despite your comments, I believe you have
PLLDIV = 78 // M = 80
So,
FOSC = FIN * PLLDIV / ((PLLPRE + 2) * 2 * (PLLPOST + 1))
FOSC = 8MHz * 80 / ((1 + 2) * 2 * (0 + 1))
FOSC = 8MHz * 80 / 6
FOSC = ~ 107 MHz

Answer 2

your pwm CONFIG for 80MHZ is right but make sure that your input frequency is 12MHZ ...i already test pwm for 80mhz with the same config of PWM and its generating proper output as you need 1KHZ. so check your PLL and Fcrystal config. i think you are generating pll 160MHZ.if you are using M=80 then you have to replace it with M=40 (PLLFBD = 38;),correct your comment or code.