Datasheet

ERM Library A
LIBRARY_SEL[2:0] = 1
ERM Library E
LIBRARY_SEL[2:0] = 5
LRA Library
LIBRARY_SEL[2:0] = 6
DRV2605
www.ti.com SLOS825C –DECEMBER 2012–REVISED SEPTEMBER 2014
Feature Description (continued)
For the LRA, the DRV2605 device automatically tracks the resonance frequency unless the LRA_OPEN_LOOP
bit in register 0x1D is set. If the LRA_OPEN_LOOP bit is set, the LRA is driven according to the frequency of the
PWM input signal. Specifically, the driving frequency is the PWM frequency divided by 128.
7.3.5.2 Internal Memory Interface
The DRV2605 device has six internal-ROM libraries designed by Immersion called TS2200. The first five libraries
are specifically tuned for five categories of ERMs operated in open-loop mode (see Table 1). Library 6 is a
closed-loop library tuned for LRAs. The library selection occurs through register 0x03 (see the (Address: 0x03)
section).
Figure 12. Library Selection
Table 1. ERM Library Table
LIBRARY RATED VOLTAGE OVERDRIVE VOLTAGE RISE TIME BRAKE TIME
A 1.3 V 3 V 40 ms to 60 ms 20 ms to 40 ms
B 3 V 3 V 40 ms to 60 ms 5 ms to 15 ms
C 3 V 3 V 60 ms to 80 ms 10 ms to 20 ms
D 3 V 3 V 100 ms to 140 ms 15 ms to 25 ms
E 3 V 3 V > 140 ms > 30 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). This augmentation
occurs only for the ROM waveforms and not for the other interfaces (such as PWM and RTP). The purpose of
this 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
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