DRV2605L-Q1 Datasheet, PDF (15/67 Pages) Texas Instruments – Automotive Haptic Driver for LRA and ERM

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DRV2605L-Q1
SLOS874A – OCTOBER 2015 – REVISED OCTOBER 2015
7.3.5.3 Real-Time Playback (RTP) Interface
The real-time playback mode is a simple, single 8-bit register interface that holds an amplitude value. When real-
time playback is enabled, the real-time playback register is sent directly to the playback engine. The amplitude
value is played until the user sends the device to standby mode or removes the device from RTP mode. The
RTP mode operates exactly like the PWM mode except that the user enters a register value over the I²C rather
than a duty cycle through the input pin. Therefore, any API (application-programming interface) designed for use
with a PWM generator in the host processor can write the data values over the I²C rather than writing the data
values to the host timer. This ability frees a timer in the host while retaining compatibility with the original
software.
For the LRA, the DRV2605L-Q1 device automatically tracks the resonance frequency unless the
LRA_OPEN_LOOP bit is set (in register 0x1D). If the LRA_OPEN_LOOP bit is set, the LRA is driven according
to the open-loop frequency set in the OL_LRA_PERIOD[6:0] bit in register 0x20.
7.3.5.4 Analog Input Interface
When the DRV2605L-Q1 device is in analog-input interface mode, the device accepts an analog voltage at the
IN/TRIG pin. The DRV2605L-Q1 device drives the actuator continuously in analog-input interface mode until the
user sets the device to standby mode or to enter another interface mode. The reference voltage in standby mode
is 1.8 V. Therefore, the 1.8-V reference voltage is interpreted as a 100% input value. A reference voltage of 0.9
V is interpreted as a 50% input value and a reference voltage of 0 V is interpreted as a 0% input value. The input
value in standby mode is analogous to the duty-cycle percentage in PWM mode.
For the LRA, the DRV2605L-Q1 automatically tracks the resonance frequency unless the LRA_OPEN_LOOP bit
is set (in register 0x1D). If the LRA_OPEN_LOOP bit is set, the LRA is driven according to the open-loop
frequency set in OL_LRA_PERIOD[6:0] bit in register 0x20.
7.3.5.5 Audio-to-Vibe Interface
The DRV2605L-Q1 device features an audio-to-vibe mode that converts an audio input signal into meaningful
haptic effects using the Immersion audio-to-vibe technology. Audio-to-Vibe mode adds a vibratory bass extension
to portable devices which allows users to feel the audio and visual content. Audio-to-Vibe mode is a key feature
because it allows for existing applications to include haptic sensations without requiring additional software
drivers. Additionally, event-driven audio effects generated within an operating system can be used to
automatically provide a product with haptic sensations. See the Waveform Playback Using Audio-to-Vibe Mode
section for details.
7.3.5.6 Input Trigger Option
The DRV2605L-Q1 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 DRV2605L-Q1 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 ROM 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).
7.3.5.6.1 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.
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