DRV2605L-Q1 Datasheet, PDF (14/67 Pages) Texas Instruments – Automotive Haptic Driver for LRA and ERM

DRV2605L-Q1
SLOS874A – OCTOBER 2015 – REVISED OCTOBER 2015
Feature Description (continued)
Table 1. ERM Library Table
LIBRARY
A
B
C
D
E
F
RATED VOLTAGE
1.3 V
3V
3V
3V
3V
4.5 V
OVERDRIVE VOLTAGE
3V
3V
3V
3V
3V
5V
RISE TIME
40 ms to 60 ms
40 ms to 60 ms
60 ms to 80 ms
100 ms to 140 ms
> 140 ms
35 ms to 45 ms
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BRAKE TIME
20 ms to 40 ms
5 ms to 15 ms
10 ms to 20 ms
15 ms to 25 ms
> 30 ms
10 ms to 20 ms
7.3.5.2.1 Waveform Sequencer
The waveform sequencer queues waveform identifiers for playback. Eight sequence registers queue up to eight
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 waveform identifier
held in register 0x05 if the next waveform is non-zero. The waveform sequencer continues in this way until it
reaches an identifier value of zero or until all eight identifiers are played (register addresses 0x04 through 0x0B),
whichever scenario is reached first.
The waveform identifier range is 1 to 127. The MSB of each sequence register can 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.
7.3.5.2.2 Library Parameterization
The ROM waveforms are augmented by the time offset registers (registers 0x0D to 0x10). The augmentation
occurs only for the ROM waveforms and not for the other interfaces (such as PWM and RTP). The purpose of
the functionality is to add time stretching (or time shrinking) to the waveform. This functionality is useful for
customizing the entire library of waveforms for a specific actuator rise time and fall time.
The time parameters that can be stretched or shrunk include:
ODT
Overdrive time
SPT
Sustain positive time
SNT
Sustain Negative Time
BRT
Brake Time
The time values are additive offsets and are 8-bit signed values. The default offset of the time values is 0.
Positive values add and negative values subtract from the time value of the effect that is currently played. The
most positive value in the waveform is automatically interpreted as the overdrive time, and the most negative
value in the waveform is automatically interpreted as the brake time. The time-offset parameters are applied to
both voltage-time pairs and linear ramps. For linear ramps, linear interpolation is stretched (or shrunk) over the
two operative points for the period (see Equation 3).
t + t_(ofs)
where
• t_(ofs) is the time offset
(3)
Changing the playback interval can also manipulate the waveforms stored in memory. Each waveform in memory
has a granularity of 5 ms. If the user desires greater granularity, a 1-ms playback interval can be obtained by
asserting the PLAYBACK_INTERVAL bit in register 0x1F.
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