DRV2604L Datasheet, PDF (35/73 Pages) Texas Instruments – DRV2604L 2- to 5.2-V Haptic Driver for LRA and ERM with Internal Memory and Smart-Loop Architecture

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DRV2604L
SLOS866D – MAY 2014 – REVISED JUNE 2015
Programming (continued)
8.5.8.2.4.1 Header Format
The header block consist of N-boundary definition blocks of 3 bytes each. N is the number of effects stored in the
RAM. Each of the boundary definition blocks contain the start address (2 bytes) and a configuration byte.
The start address contains the location in the memory where the waveform data associated with this effect
begins. The position of the effect pointer in the header becomes the effect ID. The first effect boundary definition
points to the ID for effect 1, the second definition points to the ID for effect 2, and so on. This resulting effect ID
is the effect ID that is used in the waveform sequencer.
Memory location
Header
Effect ID
0x000
0x001
0x004
0x007
Start address
upper byte
Start address
upper byte
Start address
upper byte
Revision
Start address
lower byte
Start address
lower byte
Start address
lower byte
Configuration byte Effect 1
Configuration byte Effect 2
Configuration byte Effect 3
(N ± 1) × 3 + 1
Start address
upper byte
Start address
lower byte
Configuration byte Effect N
Figure 29. Header Structure
The configuration byte contains the following two parameters:
• The effect size contains the amount of bytes that define the waveform data. An effect size of 0 is an error
state. Any odd-number effect size is an error state because the waveform data is defined as time-value (2
bytes). Therefore, the effect size must be an even number between 2 and 30.
• The WAVEFORM_REPEATS[2:0] bit is used to select the number of times the complete waveform is be
played when it is called by the waveform sequencer. A value of 0 is no repeat and the waveform is played
once. A value of 1 means 1 repeat and the waveform is played twice. A value of 7 means infinite repeat until
the GO bit is cleared.
During waveform design, ensure that the appropriate amount of drive time is at zero amplitude on the end of the
waveform so that the waveform stored in the RAM is repeated smoothly.
Configuration byte
Waveform repeats [2:0]
Effect size [4:0]
Figure 30. Header Configuration Byte Structure
8.5.8.2.4.2 RAM Waveform Data Format
The library data contents can take two forms which are voltage-time pair and linear ramp. The voltage-time pair
method implements a set and wait protocol, which is an efficient method of actuator control for most types of
waveforms. This method becomes inefficient when ramping waveforms is desired, therefore a linear ramp
method is also supported which linearly interpolates a set of voltages between two amplitude values. Both
methods require only two bytes of data per set point. The linear ramp method uses a minimum of four bytes so
that linear interpolation can be done to the next set point. The most significant bit of the voltage value is reserved
to indicate the linear ramping mode.
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