SLOS854D May 2014 – March 2018 DRV2605L
The ROM waveforms are augmented by the time offset registers (registers 0x0D to 0x10). The augmentation occurs only for the ROM waveforms and not for the other interfaces (such as PWM and RTP). The purpose of the functionality is to add time stretching (or time shrinking) to the waveform. This functionality is useful for customizing the entire library of waveforms for a specific actuator rise time and fall time.
The time parameters that can be stretched or shrunk include:
The time values are additive offsets and are 8-bit signed values. The default offset of the time values is 0. Positive values add and negative values subtract from the time value of the effect that is currently played. The most positive value in the waveform is automatically interpreted as the overdrive time, and the most negative value in the waveform is automatically interpreted as the brake time. The time-offset parameters are applied to both voltage-time pairs and linear ramps. For linear ramps, linear interpolation is stretched (or shrunk) over the two operative points for the period (see Equation 3).
Changing the playback interval can also manipulate the waveforms stored in memory. Each waveform in memory has a granularity of 5 ms. If the user desires greater granularity, a 1-ms playback interval can be obtained by asserting the PLAYBACK_INTERVAL bit in register 0x1F.