Datasheet

Table Of Contents
DA7280
LRA/ERM Haptic Driver with Multiple Input Triggers,
Integrated Waveform Memory and Wideband Support
Datasheet
Revision 3.0
30-Jul-2019
CFR0011-120-00
43 of 76
© 2019 Dialog Semiconductor
5.8.1.1 Header Section
The three sections constituting the header for the Waveform Memory are:
Byte 0: Defines the number of snippets stored.
Byte 1: Defines the number of sequences stored.
Byte 2 and onwards: The snippet(s) and sequence(s) end address pointer(s) are stored. Each
pointer address occupies one byte. Up to 15 snippets can be addressed in addition to snippet 0,
which is the silence snippet, see Note 1. Up to 16 sequences can be addressed. A snippet or
sequence pointer points to the location in the waveform memory where the last byte of the
respective snippet or sequence resides.
5.8.1.2 Data Section
The upper memory section contains the PWL data describing the snippets, see Table 17. The lower
part of the memory contains the pre-stored sequences.
Snippet IDs are determined by the order in which they are listed, starting from SNP_ID = 1.
Sequence IDs are determined by the order in which they are listed, starting from 0.
5.8.2 Snippet Definition
Snippets are formed by storing a series of one or more piecewise linear (PWL) amplitude and time
pairs. Snippets represent the basic building blocks used in the Waveform Memory.
Table 17: PWL Byte Structure
Bit
7
6
5
4
3
2
1
0
Description
RMP
TIME[6:4]
AMP[3:0]
A byte is allocated for each amplitude and time pair in the Waveform Memory, see Table 17. A
snippet consists of one or more bytes containing RMP, TIME and AMP data.
RMP defines whether a ramp (RMP = 1) or a step (RMP = 0) is required between consecutive
time and amplitude pairs.
TIME contains the unitless time information (number of timebases) with the minimum being
1 timebase. Consequently, TIME = 0 signifies time base of 1, TIME = 1 signifies time base of 2,
and so on, with the longest duration at 8 timebases for TIME = 7.
AMP contains the amplitude information of the snippet. If ACCELERATION_EN = 1, AMP is
unsigned and scales between 0 and 15, where 0 represents silence and 15 represents 100 %
drive. If ACCELERATION_EN = 0, AMP is in two's compliment and scales between 7 and -7
where 7 represents 100 % full scale and -7 represents -100 % (full scale 180° reversed polarity).
To maintain symmetry, -8 is interpreted as -7.