Philips LPC2119 User Manual page 191

Philips Semiconductors Preliminary User Manual
ARM-based Microcontroller LPC2119/2129/2292/2294
Three match registers can be used to provide a PWM output with both edges controlled. Again, the PWMMR0 match register
controls the PWM cycle rate. The other match registers control the two PWM edge positions. Additional double edge controlled
PWM outputs require only two match registers each, since the repetition rate is the same for all PWM outputs.
With double edge controlled PWM outputs, specific match registers control the rising and falling edge of the output. This allows
both positive going PWM pulses (when the rising edge occurs prior to the falling edge), and negative going PWM pulses (when
the falling edge occurs prior to the rising edge).
Figure 41 shows the block diagram of the PWM. The portions that have been added to the standard timer block are on the right
hand side and at the top of the diagram.
Pulse Width Modulator (PWM) 191 January 08, 2004