DRV2605L Datasheet, PDF (31/69 Pages) Texas Instruments – DRV2605L 2 to 5.2 V Haptic Driver for LRA and ERM With Effect Library and Smart-Loop Architecture

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DRV2605L
SLOS854C – MAY 2014 – REVISED SEPTEMBER 2014
Programming (continued)
8.5.8.2 Waveform Setup and Playback
Playback of a haptic effect can occur in multiple ways. Using the PWM mode, RTP mode, audio-to-vibe mode,
and analog-input mode can provide the waveform in real time. The waveforms can also be played from the ROM
in which case the waveform playback engine is used and the waveform is either played by an internal GO bit
(register 0x0C), or by an external trigger.
8.5.8.2.1 Waveform Playback Using RTP Mode
The user can enter the RTP mode by writing the MODE[2:0] bit to 5 in register 0x01. When in RTP mode, the
DRV2605L device drives the actuator continuously with the amplitude specified in the RTP_INPUT[7:0] bit (in
register 0x02). Because the amplitude tracks the value specified in the RTP_INPUT[7:0] bit, the I²C bus can
stream waveforms.
8.5.8.2.2 Waveform Playback Using the Analog-Input Mode
The user can enter the analog-input mode by setting the MODE[2:0] bit to 3 in register 0x01 and by setting the
N_PWM_ANALOG bit to 1 in register 0x1D. When in this mode, the DRV2605L device accepts an analog voltage
at the IN/TRIG pin. The DRV2605L device drives the actuator continuously in this mode until the user sets the
device into STANDBY mode or enters another interface mode. The reference voltage in this mode is 1.8 V.
Therefore a 1.8-V reference voltage is interpreted as a 100% input value, a 0.9-V reference voltage is interpreted
as 50%, and a 0-V reference voltage is interpreted as 0%. The input value is analogous to the duty-cycle
percentage in PWM mode. The interpretation of these percentages varies according to the selected mode of
operation. See the Data Formats for Waveform Playback section for details.
8.5.8.2.3 Waveform Playback Using PWM Mode
The user can enter the PWM mode by setting the MODE[2:0] bit to 3 in register 0x01 and bye setting the
N_PWM_ANALOG bit to 0 in register 0x1D. When in this mode, the DRV2605L device accepts PWM data at the
IN/TRIG pin. The DRV2605L device drives the actuator continuously in this mode until the user sets the device to
STANDBY mode or to enter another interface mode. The interpretation of the duty-cycle information varies
according to the selected mode of operation. See the Data Formats for Waveform Playback section for details.
8.5.8.2.4 Waveform Playback Using Audio-to-Vibe Mode
To take advantage of the audio-to-vibe feature, connect the DRV2605L device to a line-out source as shown in
Figure 59. The full-scale range of the IN/TRIG pin in the audio-to-vibe mode is 1.8 V_PP. A 0.1 µF capacitor is
recommended to AC couple the audio source and the IN/TRIG pin. For sources smaller than 1.8 V_PP, the
ATH_MAX_INPUT bit in register 0x13 can scale down the input range.
The device enters audio-to-vibe mode when the MODE[2:0] bit is set to 4 in register 0x01 and when the
AC_COUPLE bit in register 0x1B and the N_PWM_ANALOG bit in register 0x1D are set to 1. See the Register
Map section for details.
8.5.8.2.5 Waveform Sequencer
If the user uses library effects, the effects must first be loaded into the waveform sequencer, and then the effects
can be launched by using any of the trigger options (see the Waveform Triggers section for details).
The waveform sequencer (see the Waveform Sequencer (Address: 0x04 to 0x0B) section) queues waveform-
library identifiers for playback. Eight sequence registers queue up to eight library waveforms for sequential
playback. A waveform identifier is an integer value referring to the index position of a waveform in the ROM
library. Playback begins at register address 0x04 when the user asserts the GO bit (register 0x0C). When
playback of that waveform ends, the waveform sequencer plays the next waveform identifier held in register
0x05, if the next waveform is non-zero. The waveform sequencer continues in this way until the sequencer
reaches an identifier value of zero or until all eight identifiers are played (register addresses 0x04 through 0x0B),
whichever comes first.
The waveform identifier range is 1 to 123. The MSB of each sequence register can be used to implement a delay
between sequence waveforms. When the MSB is high, bits 6-0 indicate the length of the wait time. The wait time
for that step then becomes WAV_FRM_SEQ[6:0] × 10 ms.
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