DRV2604L Datasheet, PDF (17/73 Pages) Texas Instruments – DRV2604L 2- to 5.2-V Haptic Driver for LRA and ERM with Internal Memory and Smart-Loop Architecture

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DRV2604L
SLOS866D – MAY 2014 – REVISED JUNE 2015
Feature Description (continued)
8.3.5.5 Input Trigger Option
The DRV2604L device includes continuous haptic modes (such as PWM and RTP mode) as well as triggered
modes (such as the internal memory interface). The haptic effects in the continuous haptic modes begin as soon
as the device enters the mode and stop when the device goes into standby mode or exits the continuous haptic
mode. For the triggered mode, the DRV2604L device has a variety of trigger options that are explained in this
section.
In the continuous haptic modes, the IN/TRIG pin provides external trigger control of the GO bit, which allows
GPIO control to fire RAM waveforms. The external trigger control can provide improved latencies in systems
where a significant delay exists between the desired effect time and the time a GO command can be sent over
the I²C interface.
NOTE
The triggered effect must already be selected to take advantage of the lower latency. This
option works best for accelerating a pre-queued high-priority effect (such as a button
press) or for the repeated firing of the same effect (such as scrolling).
8.3.5.5.1 I²C Trigger
Setting the GO bit (in register 0x0C) launches the waveform. The user can cancel the launching of the waveform
by clearing the GO bit.
8.3.5.5.2 Edge Trigger
A low-to-high transition on the IN/TRIG pin sets the GO bit. The playback sequence indicated in the waveform
sequencer plays as normal. The user can cancel the transaction by clearing the GO bit. An additional low-to-high
transition while the GO bit is high also cancels the transaction which clears and resets the GO bit. Clearing the
trigger pin (high-to-low transition) does nothing, therefore the user can send a short pulse without knowing how
long the waveform is. The pulse width should be at least 1 µs to ensure detection.
Edge Trigger
Haptic Waveform
Edge Trigger
Cancellation
Haptic Waveform
Figure 13. Edge Trigger Mode
8.3.5.5.3 Level Trigger
The actions of the GO bit directly follow the IN/TRIG pin. When the IN/TRIG pin is high, the GO bit is high. When
the IN/TRIG pin goes low, the GO bit clears. Therefore, a falling edge cancels the transaction. The level trigger
can implement a GPIO-controlled buzz on-off controller if an appropriately long waveform is selected. The user
must hold the IN/TRIG high for the entire duration of the waveform to complete the effect.
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