DRV2604L Datasheet, PDF (36/73 Pages) Texas Instruments – DRV2604L 2- to 5.2-V Haptic Driver for LRA and ERM with Internal Memory and Smart-Loop Architecture

DRV2604L
SLOS866D – MAY 2014 – REVISED JUNE 2015
Programming (continued)
Ramp
Ramp
Waveform data
Voltage [6:0]
Time [7:0]
Voltage [6:0]
Time [7:0]
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Ramp
Voltage [6:0]
Time [7:0]
Figure 31. Waveform Data Structure
Data is stored as interleaved voltage-time pairs. Voltage in the voltage-time pair is a 7-bit signed number with
range –63 to 63 when in bidirectional mode (BIDIR_INPUT = 1), and a 7-bit unsigned number with a range of 0
to 127 when in unidirectional mode (BIDIR_INPUT = 0). The MSB of the voltage byte is reserved for the linear
ramping mode.
The Time value is the number of ticks that the Voltage will last. The size of the tick depends on the
PLAYBACK_INTERVAL bit (in register 0x1F). If PLAYBACK_INTERVAL = 0 the absolute time is number of ticks
× 5 ms. If PLAYBACK_INTERVAL = 1 the absolute time is number ticks × 1 ms.
When the most significant bit of the Voltage is high, the engine interprets a linear interpolation between that
voltage and the following voltage point. The following voltage point can either be a part of a regular voltage-time
pair, or a subsequent ramp. The following lists the sequence of bytes:
1. Byte1 — Voltage1 (MSB High)
2. Byte2 — Time1
3. Byte3 — Voltage2
4. Byte4 — Time2
The engine creates a linear interpolation between Voltage1 and Voltage2 over the time period Time1, where
Time1 is a number of 5-ms ticks. The start value for the ramp is the 7-bit value contained in Voltage1. The end
amplitude is the 7-bit value contained in Voltage2. The MSB in Voltage2 can indicate a following voltage-time
pair or the starting point in a subsequent ramp.
8.5.8.2.5 Waveform Sequencer
If the user uses pre-stored 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 RAM
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 127. 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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