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Programmer's Guide

To set the PWM Frequency for the entire IP:

  1. Clear CFG.CNTR_EN
  2. Select CFG.CLK_DIV
  3. Assert CFG.CNTR_EN

To configure the fixed PWM duty cycle and for a particular output channel (for example channel 0):

  1. Disable blinking by clearing the PWM_PARAM_0.BLINK_EN_0 bit.
  2. Set DUTY_CYCLE_0.A_0
  3. Optionally set PWM_PARAM_0.PHASE_DELAY_0 to adjust the pulse phase.
  4. Optionally assert INVERT.INVERT_0 to flip the polarity.
  5. Set PWM_EN.EN_0 to turn the channel on.

These changes will take place immediately, regardless of whether the phase_ctr is currently in the middle of a pulse cycle.

To activate simple blinking for channel 0:

  1. Set DUTY_CYCLE_0.A_0 and DUTY_CYCLE_0.B_0 to establish the initial and target duty cycles.
  2. Clear the PWM_PARAM_0.BLINK_EN_0 and PWM_PARAM_0.HTBT_EN_0 bits. This step is necessary for changing the blink timing parameters
  3. Set BLINK_PARAM_0.X_0 and BLINK_PARAM_0.Y_0 to set the number of pulse cycles respectively spent at duty cycle A and duty cycle B.
  4. Re-assert PWM_PARAM_0.BLINK_EN_0.

For synchronous blinking of a group of channels, first disable the desired channels using the PWM_EN register. Then after configuring the blink properties of the entire group, re-enable them with a single write to PWM_EN.

To activate heartbeat blinking for channel 0:

  1. Set DUTY_CYCLE_0.A_0 and DUTY_CYCLE_0.B_0 to establish the initial and target duty cycles.
  2. Clear the PWM_PARAM_0.BLINK_EN_0 bit. This step is necessary for changing the blink timing parameters
  3. Set BLINK_PARAM_0.X_0 to the number of pulse cycles between duty cycle steps (i.e. increments or decrements).
  4. Set BLINK_PARAM_0.Y_0 to set the size of each step.
  5. In a single write, assert both PWM_PARAM_0.BLINK_EN_0 and PWM_PARAM_0.HTBT_EN_0

Device Interface Functions (DIFs)