S08MP16 Flextimer PWM setup?

[abicash]

Hello (bigmac)

I am trying to output a 6 channel PWMout for a 3 phase bridge with a MP16.

For this i setup the Flextimer2 within this module for edge aligned PWM , ch0 to ch5.

This setup works okay.

Now i want to use the combine + complementary mode on all channels, so that odd numbered channels will invert the even numbered PWM pulses, and also a dead time is inserted.

I am not able to do this

I am adding my Init routine which i am unable to make work.(just for testing i have updated channel values with the ones shown)

void Timer2_init(void) {           FTM2C0SC = Channel0_Start;              FTM2C1SC = Channel0_Start; //value is 0x24             FTM2C2SC = Channel0_Start;              FTM2C3SC = Channel0_Start;              FTM2C4SC = Channel0_Start;              FTM2C5SC = Channel0_Start;    // Timer1 period       FTM2MOD = TIMER_OVERFLOW; //62.5us     FTM2MODE = 0x05 ; //WPDIS and FTMEN enabled    FTM2COMBINE0 = 0x13; //Dead time , Complementary ,combine     FTM2COMBINE1 = 0x13; //Dead time , Complementary ,combine     FTM2COMBINE2 = 0x13; //Dead time , Complementary ,combine     FTM2DEADTIME = 0x86; // 83=3us   //Initial duty cycle     FTM2C0V = FTM2C1V = FTM2C2V = FTM2C3V = FTM2C4V = FTM2C5V =  0;   //Start timer FTM2SC = 0x4A ; // for 16KHz PWM out  }   void interrupt 14 FTM2OVF (void) {         FTM2C0V = 0;         FTM2C1V = 120;//         FTM2C2V = 0;//         FTM2C3V = 140;         FTM2C4V = 0;         FTM2C5V = 160;         FTM2SC_TOF=0; } 

[abicash]

No one?

[iansmusical]

Hi Abhijit,

I can't help you directly and I know it's obvious but have you checked the Freescale website? A quick "flextimer" search gave me several motor control application notes:

Freescale Search

Thanks,

Ian

[weapon]

Hi Jagtap,

If (CLKS[1:0] not = 00 and FTMEN = 1) then FTMxCnVH:L registers are updated by PWM synchronization. For detailed info about PWM synchronization,please take refer to Section 12.5.11 of the reference manaul.

that means channel registers can't be loaded in the overflow ISR.  If you wrote those channel registers before start the timer(CLKS = 0), then  those value can be loaded immediately.Like below.

    FTM2C0SC = Channel0_Start;

    FTM2C1SC = Channel0_Start; //value is 0x24  
    FTM2C2SC = Channel0_Start;
    FTM2C3SC = Channel0_Start;
    FTM2C4SC = Channel0_Start;
    FTM2C5SC = Channel0_Start;     // Timer1 period
    FTM2MOD = TIMER_OVERFLOW; //62.5us   10.  
    FTM2MODE = 0x05; //WPDIS and FTMEN enabled   11.  
    FTM2COMBINE0 = 0x13; //Dead time , Complementary ,combine   12. 
    FTM2COMBINE1 = 0x13; //Dead time , Complementary ,combine   13. 
    FTM2COMBINE2 = 0x13; //Dead time , Complementary ,combine    14.  
    FTM2DEADTIME = 0x86; // 83=3us     15.//Initial duty cycle    16. 
    FTM2C0V = FTM2C1V = FTM2C2V = FTM2C3V = FTM2C4V = FTM2C5V = 0;
    //Start timer   18.

// load channel registers below.
    FTM2C0V = 0;
     FTM2C1V = 120; // 
     FTM2C2V = 0;//  
     FTM2C3V = 140;
     FTM2C4V = 0;
     FTM2C5V = 160;
    FTM2SC = 0x4A; // start time

Hope it can solve your problem.

B.R

XWP

[abicash]

Hi Weiping

Can you write an init code for me?

I have channels 0,2,4 as complementary pairs of channels 1,3,5

I want to combine these pairs and add a deadtime between switching.

I have written this in every possible way with every possible register_bit enabled/disabled

I update the FTM2CnV values in its overflow register

[abicash]

Hello

Strangely an initialisation which the reference manual prohibits from using is giving me results what i require.

void Timer2_init(void) 
 {
   FTM2MOD = TIMER_OVERFLOW; //62.5us 
    FTM2COMBINE0 =   FTM2COMBINE0_DTEN_MASK | FTM2COMBINE0_COMP_MASK ;//| FTM2COMBINE0_COMBINE_MASK;
//The ref. manual says that the COMPLEMENTARY mode CANNOT be used without COMBINE mode
//I ignored it to see what happens
    FTM2COMBINE1 =   FTM2COMBINE0_DTEN_MASK | FTM2COMBINE0_COMP_MASK;//| FTM2COMBINE0_COMBINE_MASK;
    FTM2COMBINE2 =   FTM2COMBINE0_DTEN_MASK | FTM2COMBINE0_COMP_MASK;// | FTM2COMBINE0_COMBINE_MASK;
    FTM2DEADTIME = 0x8C; // 8C=16MHz (sys clock)/4 = 4MH(250ns) 
//250ns x 48 clock cycles = 12us, whereas i get close to 2us
        FTM2C0SC = Channel_even_Start;// 0x28 , Edge aligned PWM , high true pulses
        FTM2C1SC = Channel_odd_Start; // 0-1 channels in same limb or half bridge
        FTM2C2SC = Channel_even_Start;//0x24, Edge aligned PWM , Low true pulses
        FTM2C3SC = Channel_odd_Start;
        FTM2C4SC = Channel_even_Start;
        FTM2C5SC = Channel_odd_Start; 
    FTM2C0V = 0;
    FTM2C1V = 0;// init all values to 0
    FTM2C2V = 0;
    FTM2C3V = 0;
    FTM2C4V = 0;
    FTM2C5V = 0;
FTM2SC = 0x49; // for 16KHz (8MHz/2 = 4MHz and MODULO count is 249)
}

void interrupt 14 FTM2OVERFLOW ISR(void)
{
    // do some work and then update channel registers

        FTM2C0V = sin_table[Duty_Cycle1]; // High true pulses
        FTM2C1V = sin_table[Duty_Cycle1]; //Low true pulses 
//same values since same limb but different pulses 
        FTM2C2V = sin_table[Duty_Cycle2];
 
        FTM2C3V = sin_table[Duty_Cycle2];
        FTM2C4V = sin_table[Duty_Cycle3];
        FTM2C5V = sin_table[Duty_Cycle3];
        FTM2SC_TOF = 0 ;
}

  so you see. SO many things happening with prohibited usages

1)FTM2MODE = 0, and still DTVAL and DTPS can be written

2)COMPLEMENTARY mode used Without COMBINE mode

3)DEADTIME value written something else and result is something else

Please someone explain

[weapon · Accepted solution]

Hi,

Actually, you still didn't understand well about PWM synchronization. please read that section(12.5.11) carefully, but not use those configuration we are not recommended, if you use those configurations, the results are not guaranteed.

Hope you understand.

B.R

XWP

[abicash]

I really don't understand why the initialisation you provided does not work?

I have read the document for at least 5 times since morning and got what SWSYNC and CNTIN does

Yet the provided code and the ones altered here do not work.

Am really worried now :smileysad:

[abicash]

Hi

It is working now with a bit of tinkering :smileyhappy:

FTM2CNTIN = TIMER_OVERFLOW/2;// does not work

FTM2CNTIN = 0; // works

One more rudimentary mistake i was making was regards the Clock to timer.

In TPMv2 and v3 CLKSB:CLKSA = 01 was BUS CLOCK

whereas in FLEXTIMER it is ICSOUT (When FTMEN =1)

Silly of me to overlook that

Otherwise now i observe proper sync between adjacent channels and calculated dead times appear on scope

Thanks for the support.Appreciated

[weapon]

Hi,

Please try to use following routines.

void Timer2_init(void)
{
    FTM2C0SC = Channel0_Start;

    FTM2C1SC = Channel0_Start; //value is 0x24  
    FTM2C2SC = Channel0_Start;
    FTM2C3SC = Channel0_Start;
    FTM2C4SC = Channel0_Start;
    FTM2C5SC = Channel0_Start;     // Timer1 period
    FTM2MOD = TIMER_OVERFLOW; //62.5us   10.  
    FTM2MODE = 0x05; //WPDIS and FTMEN enabled   11.
    FTM2SYNC |= 0x01; // load buffer when counter matches with FTM2CNTIN
    FTM2CNTIN = TIMER_OVERFLOW/2; // load buffer when counter counts up to half of modulo
    FTM2COMBINE0 = 0x33; //Dead time , Complementary ,combine   12. 
    FTM2COMBINE1 = 0x33; //Dead time , Complementary ,combine   13. 
    FTM2COMBINE2 = 0x33; //Dead time , Complementary ,combine    14.  
    FTM2DEADTIME = 0x86; // 83=3us     15.//Initial duty cycle    16. 
    FTM2C0V = FTM2C1V = FTM2C2V = FTM2C3V = FTM2C4V = FTM2C5V = 0;
    FTM2SC = 0x4A; // for 16KHz PWM out   19.
    //Start timer   18.
}

interrupt  void FTM2OVF_ISR (void)
{
    FTM2SC_TOF=0;
    FTM2C0V = 0;
    FTM2C1V = 120; // 
    FTM2C2V = 0;//  
    FTM2C3V = 140;
    FTM2C4V = 0;
    FTM2C5V = 160;
    FTM2SYNC_SWSYNC = 1;  
}

B.R

XWP

[abicash]

Hello Weiping

Thanks for the snippet

Unfortunately, it isn't working :smileysad:

The port pins associated with the Timers will never change state.

Even numbered channels stay at 0v and odd numbered channels stay at 5v.

I do not see any pulses

[abicash]

Hi Weiping thanks for replying

First of all i want you to know that I am really tired now with all this :smileycry:

I used the same settings in the same sequence.

Some unexplained things happen

1)Even though CHnIE is disabled , the CHnF is set and the program just hangs

2)Sometimes it functions correctly but i see that FTMCnV is not updated in the overflow ISR where i manually upload new values for the channel.

3)My Channel pins remain inactive throughout the state.

iansmusical I have checked a lot of documents and i believe i am doing the right things, yet no result

heres my init code
{
      FTM2C1SC = Channel_odd_Start;
      //  FTM2C2SC = Channel_even_Start;
        FTM2C3SC = Channel_odd_Start;
      //  FTM2C4SC = Channel_even_Start;
        FTM2C5SC = Channel_odd_Start; 
        FTM2MOD = TIMER_OVERFLOW; //62.5us 
      //  FTM2FMS_WPEN =0;
        FTM2MODE |= 0x05 ; //WPDIS and FTMEN enabled
        FTM2COMBINE0 |= 0x13; //Dead time , Complementary ,combine
        FTM2COMBINE1 |= 0x13; //Dead time , Complementary ,combine
        FTM2COMBINE2 |= 0x13; //Dead time , Complementary ,combine 
        FTM2DEADTIME |= 0x86; // 83=3us  
        
        FTM2C0V = 0;
    FTM2C1V = 0;
    FTM2C2V = 0;
    FTM2C3V = 0;
    FTM2C4V = 0;
    FTM2C5V = 0;
        
                  
      FTM2SC = TIMER_START;
}

heres my ISR bit

FTM2C1V = sin_table[Duty_Cycle1]+125;//120 Deg apart+21
       // R_BAR =0 ;
     //   FTM2C2V = sin_table[Duty_Cycle2]+125;//240 Deg apart+10
       // Y_BAR =0 ;
        FTM2C3V = sin_table[Duty_Cycle2]+125;
    //    FTM2C4V = sin_table[Duty_Cycle3]+125;//120 Deg apart+21
        FTM2C5V = sin_table[Duty_Cycle3]+125;//240 Deg apart+10
       // B_BAR =0 ;
        FTM2SC_TOF = 0 ;

I find that the FTM2CnV values never update

[abicash]

Hello

I am running into a lot of troubles.

Can someone help please?