32 bit timer; PWM going to completley on state at non regular intervals

[lpcware]

Content originally posted in LPCWare by george.thaliath on Tue Nov 19 23:20:38 MST 2013
Hi,
I have been working on the LPC1114's 32 bit timer.(configured as PWM)
I am changing the PWM duty cycle at a regular interval of 33Hz
while going through the output of the micro, it was noted that the PWM pulse was going to a full hight state for one complete timer period.
This abnormal operation is repeated at NON REGULAR intervals.

The piece of code also has UART and WDT in it.
I did check if the WDT was making the system reset(it is not)

It would be great if some one there could point me in which direction to look. or the cause for this to happen.

thanks in advance.

Cheers.

[lpcware]

Content originally posted in LPCWare by george.thaliath on Wed Nov 20 16:06:43 MST 2013
/*********************************************************************************/

Main

/*********************************************************************************/

start loop

Declare all the pins

check vor valid data on the UART

update PWM

Repeat update PWM if or not valid data (refresh rate is around 200Hz)

end loop


/*********************************************************************************/

config(delcaration of port pins and init)

/*********************************************************************************/


void TickHandler(void)
{
    uint32_t i;
    uint32_t millisec_increment = 1000 / SYS_TICK_RATE_HZ;
   
    sys_millisec_cnt += millisec_increment;
    if (sys_millisec_cnt >= 1000)
    {
        sys_millisec_cnt -= 1000;
        sys_seconds_cnt++;
        led_state ^= 1;
#ifndef PROTOTYPE_BOARD
        if (led_state) {
            LPC_GPIO0->DATA |=  (1 << 2); /* Led on P0.2 off */
        } else {
            LPC_GPIO0->DATA &= ~(1 << 2); /* Led on P0.2 on */
        }
#else
        if (led_state) {
            LPC_GPIO0->DATA |=  (1 << 7); /* Led on P0.7 */
        } else {
            LPC_GPIO0->DATA &= ~(1 << 7); /* Led on P0.7 */
        }
#endif
    }
    for (i=0; i<NR_OF_MSEC_COUNTERS; i++)
    {
        app_millisec_cnt += millisec_increment;
    }
}

void bsp_init(void)
{
    uint32_t i;
   
    /* Init global variables */
    led_state = 0;
    sys_seconds_cnt = 0;
    sys_millisec_cnt = 0;
    for (i=0; i<NR_OF_MSEC_COUNTERS; i++)
    {
        app_millisec_cnt_avail = true;
    }

    /* Setup the system tick timer */
    NVIC_SetPriority(SysTick_IRQn, SYSTICK_IRQ_PRIORITY);
    SysTick_Config(LPC_CORE_CLOCKSPEED_HZ / SYS_TICK_RATE_HZ);

#ifdef SUPPORT_I2C_BUS
    LPC_SYSCON->PRESETCTRL |= (1 << 1);
#endif
   
    LPC_SYSCON->SYSAHBCLKCTRL |= (1 <<  6) |  /* Enable AHB clock to the GPIO domain */
#ifdef SUPPORT_I2C_BUS
                                 (1 <<  5) |  /* Enable AHB clock to the I2C */
#endif
                                 (1 <<  7) |  /* Enable AHB clock to the 16-bit counter/timer 0 */
                                 (1 <<  8) |  /* Enable AHB clock to the 16-bit counter/timer 1 */
                                 (1 <<  9) |  /* Enable AHB clock to the 32-bit counter/timer 0 */
                                 (1 <<  10)|  /* Enable AHB clock to the 32-bit counter/timer 1 */
                                 (1 <<  12) |  /* Enable AHB clock to the UART */
                                 (1 <<  15);   /* Enable AHB clock to the WDT */
   
    /* Configuring LED pin P0.3 (traffic LED) */
    LPC_IOCON->PIO0_3 = 0xC0;     // select PIO mode, no pull up/down, disable hysteresis
    LPC_GPIO0->DIR |= (1 << 3);   // set PIO pin P0.3 as output
#ifndef PROTOTYPE_BOARD
    /* Configuring LED pin P0.2 (heartbeat LED) */
    LPC_IOCON->PIO0_2 = 0xC0;     // select PIO mode, no pull up/down, disable hysteresis
    LPC_GPIO0->DIR |= (1 << 2);   // set PIO pin P0.2 as output
    /* Configure pin P0.7 for DMX bus data direction control */
    LPC_IOCON->PIO0_7 = 0xC0;     // select PIO mode, no pull up/down, disable hysteresis
    LPC_GPIO0->DIR |= (1 << 7);   // set PIO pin P0.7 as output
#else
    /* Configuring LED pin P0.7 */
    LPC_IOCON->PIO0_7 = 0xC0;     // select PIO mode, no pull up/down, disable hysteresis
    LPC_GPIO0->DIR |= (1 << 7);   // set PIO pin P0.7 as output
    /* Configure pin P2.6 for DMX bus data direction control */
   // LPC_IOCON->PIO2_6 = 0xC0;     // select PIO mode, no pull up/down, disable hysteresis
  //  LPC_GPIO2->DIR |= (1 << 6);   // set PIO pin P2.6 as output
#endif
   // bsp_recv_from_dmx_bus();
        /* Configuring the DIP switches P2.1, P2.4, P3.5 and P0.6 */
        LPC_IOCON->PIO2_1 = 0xC8;     // select PIO mode, pull up, disable hysteresis DV
        LPC_GPIO2->DIR &= ~(1 << 1);  // set PIO pin P2.1 as input  Bit-0
        LPC_IOCON->PIO2_4 = 0xC8;     // select PIO mode, pull up, disable hysteresis   DV
        LPC_GPIO2->DIR &= ~(1 << 4);  // set PIO pin P2.4 as input  Bit-1
        LPC_IOCON->PIO3_5 = 0xC8;    // select PIO mode, pull up, disable hysteresis  DV
        LPC_GPIO3->DIR &= ~(1 << 5); // set PIO pin P3.5 as input  Bit-2
        LPC_IOCON->PIO0_6 = 0xC8;    // select PIO mode, pull up, disable hysteresis  DV
        LPC_GPIO0->DIR &= ~(1 << 6); // set PIO pin P0.6 as input  Bit-3

       // dmx_set_to_dmx_bus();
        LPC_IOCON->PIO2_11 = 0xC0;     // select PIO mode, pull up, disable hysteresis
        LPC_GPIO2->DIR |= (1 << 11);   // set PIO pin P2.11 as output X1
        LPC_IOCON->PIO2_2 = 0xC0;     // select PIO mode,pull up, disable hysteresis
        LPC_GPIO2->DIR |= (1 << 2);   // set PIO pin P2.2 as output  X10
        LPC_IOCON->PIO2_10 = 0xC0;     // select PIO mode,pull up, disable hysteresis
        LPC_GPIO2->DIR |= (1 << 10);   // set PIO pin P2.10 as output X100
        LPC_IOCON->PIO2_9 = 0xC0;     // select PIO mode,pull up, disable hysteresis
        LPC_GPIO2->DIR |= (1 << 9);   // set PIO pin P2.9 as output  Mode

      //  Analog_Channel_Set(1);
        LPC_IOCON->PIO2_7 = 0xD0;     // select PIO mode, pull up, disable hysteresis
        LPC_GPIO2->DIR |= (1 << 7);   // set PIO pin P2.7 as output S1
        LPC_IOCON->PIO2_8 = 0xD0;     // select PIO mode, pull up, disable hysteresis
        LPC_GPIO2->DIR |= (1 << 8);   // set PIO pin P2.8 as output S2
        LPC_IOCON->PIO3_2 = 0xD0;     // select PIO mode, pull up, disable hysteresis
        LPC_GPIO3->DIR |= (1 << 2);   // set PIO pin P3.2 as output S0

        LPC_GPIO2->DATA |=  (1 << 7);
        LPC_GPIO2->DATA |=  (1 << 8);
        LPC_GPIO3->DATA |=  (1 << 2);
//start of wL control pin and Wlink control
        LPC_IOCON->PIO0_8 = 0xC0;     // select PIO mode, pull up, disable hysteresis DV
        LPC_GPIO0->DIR &= ~(1 << 8);  // set PIO pin P2.1 as input  Bit-0
        LPC_GPIO0->DATA |=  (1 << 8);
//end of WL control pin
        //to be removed, this is been set for demo
        LPC_IOCON->PIO1_11 = 0xC0;
        LPC_GPIO1->DIR |= (1 << 11);

        LPC_IOCON->PIO1_4 = 0xC0;
        LPC_GPIO1->DIR |= (1 << 4);


    /* Configure CT32B0 and CT32B1 match pins 0 and 1 */
    LPC_IOCON-> PIO2_5           &= ~0x07;
    LPC_IOCON-> PIO2_5            |= 0x01; // select CT32B0_MAT0

    LPC_IOCON-> PIO2_6           &= ~0x07;
    LPC_IOCON-> PIO2_6            |= 0x01;// select CT32B0_MAT1

    LPC_IOCON->PIO0_1  = 0xE2;   //CA;    // select CT32B0_MAT2
    Timer_PWM_Init(CT32B0);
    LPC_IOCON->JTAG_TDO_PIO1_1  &= ~0x07;
    LPC_IOCON->JTAG_TDO_PIO1_1  |= 0x03;/* Timer1_32 MAT0 */
    LPC_IOCON->JTAG_nTRST_PIO1_2 &= ~0x07;
    LPC_IOCON->JTAG_nTRST_PIO1_2 |= 0x03;/* Timer1_32 MAT1 */
    LPC_IOCON->ARM_SWDIO_PIO1_3  &= ~0x07;
    LPC_IOCON->ARM_SWDIO_PIO1_3  |= 0x03;/* Timer1_32 MAT2 */

   

   Timer_PWM_Init(CT32B1);
   dim_leds(0,0,0,0,0,0,0);
    /* Configuring UART RXD pin */
    LPC_IOCON->PIO1_6 = 0xD1;     // select RXD mode, pull up, disable hysteresis
    /* Configuring UART TXD pin */
    LPC_IOCON->PIO1_7 = 0xD1;     // select TXD mode, pull up, disable hysteresis
    Uart_Init();

#ifdef SUPPORT_I2C_BUS
    /* Configuring I2C SCL pin */
    LPC_IOCON->PIO0_4 = 0x0001;   // select SCL mode, standard mode
    /* Configuring I2C SDA pin */
    LPC_IOCON->PIO0_5 = 0x0001;   // select SDA mode, standard mode
    I2C_Init(I2CMASTER,0,0,0);
    lcd_init();
#endif

#ifdef SUPPORT_MANUAL_CONTROL
    /* Configuring joystick pins P3.0, P3.1, P2.3, P3.3 */
    LPC_IOCON->PIO3_0 = 0xC8;// select PIO mode, disable hysteresis
    LPC_GPIO3->DIR &= ~(1 << 0);
    LPC_IOCON->PIO3_1 = 0xC8;     // select PIO mode, disable hysteresis
    LPC_GPIO3->DIR &= ~(1 << 1);
    LPC_IOCON->PIO2_3 = 0xC8;     // select PIO mode, disable hysteresis Deepak Varma
    LPC_GPIO2->DIR &= ~(1 << 3);
    LPC_IOCON->PIO3_3 = 0xC8;     // select PIO mode, disable hysteresis
    LPC_GPIO3->DIR &= ~(1 << 3); // set PIO pin P2.3 as input
#endif

    //setting up the emergency pins on the micro controller
    //pin numbers 33 is Em on
    //pin number 45 is EM off

    //pin number 45
    LPC_IOCON->PIO1_5 = 0xD0;// select PIO mode, disable hysteresis
    LPC_GPIO1->DIR &= ~(1 << 5);// set as input
    //setting pin number 33
    LPC_IOCON->JTAG_TMS_PIO1_0 = 0xD0;// select PIO mode, disable hysteresis
    LPC_GPIO1->DIR &= ~(1 << 0);// set as input




    WDT_Init(10);                  // 10 seconds timeout
}







/*********************************************************************************/

init of the timer

/*********************************************************************************/



void Timer_PWM_Init(uint8_t ctId)
{
    uint32_t pclk_freq = SystemAHBFrequency;/* get the clock of the timer unit */
    uint32_t pwmfrq = pclk_freq / PWM_FREQ;

  switch (ctId)
   {
    case CT32B0:
        LPC_TMR32B0->TCR  = 0x02;     /* disable and reset this CounterTimer */
        LPC_TMR32B0->PR   = 0x00;     /* set prescaler to zero */
        LPC_TMR32B0->MR3  = pwmfrq;   /* set the default frequency in MR3 */
        Timer_PWM_Set_Duty_Cycle(ctId, CTMAT0, PWM_DUTY, PWM_DUTY, PWM_DUTY, PWM_DUTY, PWM_DUTY, PWM_DUTY,2,4);
        Timer_PWM_Set_Duty_Cycle(ctId, CTMAT1, PWM_DUTY, PWM_DUTY, PWM_DUTY, PWM_DUTY, PWM_DUTY, PWM_DUTY,2,4);
        Timer_PWM_Set_Duty_Cycle(ctId, CTMAT2, PWM_DUTY, PWM_DUTY, PWM_DUTY, PWM_DUTY, PWM_DUTY, PWM_DUTY,2,4);
        LPC_TMR32B0->MCR  = 0x400;    /* reset timer on match of MR3, no interrupts */
        LPC_TMR32B0->PWMC = 0x07;     /* select PWM mode for CT32B0_MAT0 ,CT32B0_MAT1 and CT32B0_MAT2 */
        LPC_TMR32B0->IR   = 0x1F;     /* reset all interrupt flags */
        LPC_TMR32B0->CTCR = 0x00;     /* use the CounterTimer in timer mode */
        LPC_TMR32B0->TCR  = 0x01;     /* CounterTimer enable */
        break;
    case CT32B1:
        LPC_TMR32B1->TCR  = 0x02;     /* disable and reset this CounterTimer */
        LPC_TMR32B1->PR   = 0x00;     /* set prescaler to zero */
        LPC_TMR32B1->MR3  = pwmfrq;   /* set the default frequency in MR3 */
        Timer_PWM_Set_Duty_Cycle(ctId, CTMAT0, PWM_DUTY, PWM_DUTY, PWM_DUTY, PWM_DUTY, PWM_DUTY, PWM_DUTY,2,4);
        Timer_PWM_Set_Duty_Cycle(ctId, CTMAT1, PWM_DUTY, PWM_DUTY, PWM_DUTY, PWM_DUTY, PWM_DUTY, PWM_DUTY,2,4);
        Timer_PWM_Set_Duty_Cycle(ctId, CTMAT2, PWM_DUTY, PWM_DUTY, PWM_DUTY, PWM_DUTY, PWM_DUTY, PWM_DUTY,2,4);
        LPC_TMR32B1->MCR  = 0x400;    /* reset timer on match of MR3, no interrupts */
        LPC_TMR32B1->PWMC = 0x07;     /* select PWM mode for CT32B1_MAT0 , CT32B1_MAT1 and CT32B1_MAT2 */
        LPC_TMR32B1->IR   = 0x1F;     /* reset all interrupt flags */
        LPC_TMR32B1->CTCR = 0x00;     /* use the CounterTimer in timer mode */
        LPC_TMR32B1->TCR  = 0x01;     /* CounterTimer enable */
        break;


    default:
        break;
    }
}

[lpcware]

Content originally posted in LPCWare by george.thaliath on Wed Nov 20 16:03:26 MST 2013
Hi mate,
change in PWM is done by just changing the count up value
as shown below.

//PWMPulse changes value from 0 to 9600 which is what decides the duty of the PWM
LPC_TMR32B0->MR1=9600-PWMPulse ;


I really did not understand, what u ment by sync before change.

could you please explain.

Thanks. :)

[lpcware]

Content originally posted in LPCWare by wmues on Wed Nov 20 01:18:11 MST 2013
How do you synchronize the writing of a new PWM value to the current PWM counter value?

[lpcware]

Content originally posted in LPCWare by R2D2 on Wed Nov 20 00:11:43 MST 2013

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Quote: george.thaliath
It would be great if some one there could point me in which direction to look. or the cause for this to happen.

---

To see a bit of code could be helpful...