CC2541: PWM using Timer4 free-runing with Set output on compare-up, clear on 0

Ju Young Kim

Prodigy 20 points

Part Number: CC2541

I corded as below for motor throttling using PWM. "motorPWM" will run when speed value is changed from a smartphone.

I used Timer4 with "free-runing mode" with "Set output on compare-up, clear on 0" mode to make PWM signal.

PWM siganl changes well until 50% duty as "speed" value increases to 127.

When "speed value" is over 127 such as 128 and more, duty becoms suddenly 0%.

Could you anyone let me know what is wrong or missing in my cord?

/** \brief Motor reference value */
#define MOTER1_CENTER 0
#define MOTER2_CENTER 0

//Initialize Timer 4
    T4CC1 = MOTER1_CENTER;
    T4CC0 = MOTER1_CENTER;
    T4CCTL0 = 0x1C;              //IM=0, SET OUT ON COMPARE-UP, CLEAR ON 0 output on compare (00011100)
    T4CCTL1 = 0x1C;
    T4CTL = 0xE4;;

void motorPWM(int8 speed)
{


if (speed > 2)
    {T4CC0 = ~speed;    // PWM VALUE FOR MOTOR 1
     T4CC1 = ~speed;    // PWM VALUE FOR MOTOR 1
     T4CTL |= 0x10;                   // Timer 4 Start
    }
else
    {
      T4CTL &= ~0x10;     // Timer 4 Stop
      T4CTL |= 0x04;      // Timer 4 Clear
      T4CC0 = 0;          // PWM = 0 for Motor1
      T4CC1 = 0;          // PWM = 0 for Motor2
      }
}