DA7281 datasheet(40/88 Pages) RENESAS

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DA7281

LRA/ERM Haptic Driver with Multiple I²C

Addresses, Integrated Waveform Memory, and

Wideband Support

Datasheet

Revision 3.1

10-Feb-2022

CFR0011-120-00

40 of 87

ACCELERATION_EN = 0 and RAPID_STOP_EN = 0. There are two ways to operate DA7281 during

wideband operation:

● In the limited frequency range of 25 Hz to 300 Hz:

○ No further settings are required in RTWM and ETWM modes if the frequency information is

already stored in the Waveform Memory frame data as described in Section 5.8.3. If the

Waveform Memory does not contain frequency information, then each sequence can be

played at a different frequency by setting LRA_PER_H and LRA_PER_L to the desired value

via the formulae in Section 5.6.2 before triggering playback using the method described in

Sections 5.6.5.4 and 5.6.5.5.

○ In the DRO and PWM modes, the frequency information can be updated via the LRA_PER_H

and LRA_PER_L using the formulae in Section 5.6.2 either before triggering playback of

each sequence, see Sections 5.6.5.2 and 5.6.5.3, or during the playback itself. As with

amplitude, the one half-period uncertainty on the output frequency update also applies.

● In the full range of 25 Hz to 1024 Hz, the same procedures apply for all modes, but the following

registers need to be set:

○ BEMF_SENSE_EN = 0

○ DELAY_H = 0

○ DELAY_SHIFT_L = 0

○ DELAY_FREEZE = 1

5.7.6

Custom Waveform Operation

With frequency tracking, Active Acceleration, and Rapid Stop disabled, and with the additional setup

for wideband operation described in Section 5.7.5, DA7281 can be configured to drive a custom

waveform to an LRA actuator. It is important to note that here the custom waveform denotes the

actual output during a single LRA resonant period and not the overall amplitude envelope during

drive events, which is controlled as previously described in Section 5.6.5. Amplitude and frequency

data can be streamed as usual in DRO, PWM, RTWM, or ETWM modes.

The waveform output during a single resonant period comprises of 16 distinct points, see Figure 18,

where points 0 to 4 are mirrored and repeated to create, by default, a sine wave (for example, point 3

and point 5, and point 2 and point 6 have the same amplitude).

DA7281 Datasheet(PDF) 40 Page - Renesas Technology Corp