How to output PWM from CC2530/CC2541

Refer to CC253x/4x User's Guide. The following sample code can send PWM to P1_4.


  PERCFG &= (~(0x20)); // Select Timer 3 Alternative 1 location
  P2SEL |=0x20;
  P2DIR |= 0xC0;  // Give priority to Timer 1 channel2-3
  P1SEL |= BV(4);  // Set P1_4 to peripheral, Timer 1,channel 2
  P1DIR |= BV(4);

  T3CTL &= ~0x10;             // Stop timer 3 (if it was running)
  T3CTL |= 0x04;              // Clear timer 3
  T3CTL &= ~0x08;             // Disable Timer 3 overflow interrupts
  T3CTL |= 0x03;              // Timer 3 mode = 3 - Up/Down

  T3CCTL1 &= ~0x40;           // Disable channel 0 interrupts
  T3CCTL1 |= 0x04;            // Ch0 mode = compare
  T3CCTL1 |= 0x10;            // Ch0 output compare mode = toggle on compare

  T3CTL &= ~0xE0;   // Clear Prescaler divider value
  T3CTL |= 0xA0;    //Set Prescaler divider value = Tick frequency /32
  T3CC0 = 128;      //Set ticks = 128

  // Start timer
  T3CTL |= 0x10;

Then, the following example shows you how you output 6.5K PWM with 50% duty cycle to P1.1 with CC2530 Timer 1.

  PERCFG |= BV(6); // Select Timer 1 Alternative 2 location
  P2DIR = (P2DIR & ~0xC0) | 0x80; // Give priority to Timer 1
  P1SEL |= BV(1);  // Set P1_1 to peripheral

  T1CC0L = 0x3A;   // PWM signal period
  T1CC0H = 0x01;

  T1CC1L = 0x9D;  // PWM duty cycle
  T1CC1H = 0x00;

  T1CCTL1 = 0x1c;

  T1CTL |= (BV(2)|0x03); // divide with 128 and to do i up-down mode