Datasheet

f f-

S IN

f + f

S IN

First-order filter

Second-order filter

General Operation

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Table 6 lists the MSP430G2553 pinout on the DRV8662EVM.

Table 6. DRV8662EVM MSP430 Pinout

Pin No. Label Description

1 P1.1 GAIN0

2 P1.2 GAIN1

3 P1.3 EN / ACTIVE

12 P3.2 PWM+

13 P3.3 PWM–

17 P2.5 TRIG (Pushbutton)

21 P1.6/SCL I

C Clock

22 P1.7/SDA I

C Data

23 SBWTDIO Spy-Bi-Wire Data

24 SBWTCK Spy-Bi-Wire Clock

25 P2.7 GAIN1 FET Control

26 P2.6 GAIN0 FET Control

27 AVSS Analog Ground

28 DVSS Digital Ground

29 AVCC Analog Supply

30 DVCC Digital Supply

3.5 Filtering and Adapting PWM Waveforms

The DRV8662EVM has the capability to support many different input filter configurations. Depending on

the input mode, input frequency and input voltage the filter can be adapted to attenuate any undesired

out-of-band content. This section describes the input filter requirements and the various respective

configurations.

3.5.1 PWM Input

When using a PWM input, a low-pass filter is required. The primary parameters for determining the input

filter are the PWM input frequency and sample rate. Because haptic waveforms are typically less than 500

Hz, the input filter must attenuate frequencies above 500 Hz. For samples rates above 20 kHz, a simple

first-order RC filter is recommended; however, for sample rates much lower (such as 8 kHz), a first-order

filter may not sufficiently attenuate the high-frequency content. Thus, for lower sampling rates, a second-

order RC filter may be required. The following sections describe example filter configurations for both first-

order and second-order filters. The DRV8662EVM default configuration uses a second-order, differential

filter, but it can be replaced by a first-order, single-ended or differential filter.

Figure 7. Filter Response

DRV8662 Piezo Haptics Driver Evaluation Module SLOU319A–August 2011–Revised December 2012

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