SLOS751D March 2013 – November 2018 DRV2667
The Direct Playback from RAM mode makes use of the on-chip 2 kB of RAM for internal waveform storage. This mode allows for immediate, low-latency recall of arbitrary haptic waveforms with very little intervention from the host processor. Haptic waveforms, be they simple or complex, may be stored in this memory at opportune times when immediate processor response is not critical. Examples of this are when the end-user product is being powered up and initialized or when an application is being launched.
The waveforms are stored as 8-bit twos-complement, Nyquist-rate data points, and are played from RAM at an 8-kHz data rate. Up to 250 ms of total waveform playback time may be stored in the Direct Playback From RAM mode format in the 2-kB memory. The waveform sizes are completely customizable, so many small waveforms may be stored or fewer long ones. The sum of the waveform lengths must not be greater than the 2-kB RAM size.