ADAU1445 Analog Devices, ADAU1445 Datasheet - Page 81

• Manufacturer Part Number: ADAU1445
• Manufacturer: Analog Devices

Specifications of ADAU1445

• Instructions/cycles: 3584
• Digital I/o Channels: 24/24
• Analog I/o Channels: 0/0
• Product Description: Digital audio processor with flexible audio routing matrix, 8 × 2-channel ASRC

SOFTW
SOFTWARE SA
To upda
noises on t
use a software safeload mechanism. SigmaStudio automatically
sets up the necessary code and parameters for new projects. The
sa
36 locations in program RAM. The first eight parameter RAM
locations (Address 0x0000 to Address 0x0007) are configured
by default in SigmaStudio as described in Table 81.
Tab
Address 0x0000, which co
Si
m
A
the safeload data. The safelo
sl
have five parameters or fewer.
Address 0x0006 is the target address in parameter RAM (with
an offset of −1). This designates the first address to be written.
If more than
au
addr
th
if the
ta
A
Fo
Address
(Hex)
0x0000
0x0001
0x0002
0x0003
0x0004
0x0005
0x0006
0x0007
ots by default because mo
ddress 0x0001 to Addres
ddress 0x0007 designate
gmaStudio and is based
rget address should be 0
feload code, along with other initialization code, fills the first
e address of the data, wh
ode of the project.
tomatically for each da
r a biquad filter, the nu
le 81. Software Safel
ess offset of −1 is that t
intention is to upda
te parame
he outp
ARE F
one word is
ut, the
ters in
Functi
Modulo RAM size
Safeload Data 1
Safeload Data 2
Safeload Data 3
Safeload Data 4
Safeload Data 5
Safeload target address (offset of −1)
Numbe
FELO
EATURES
ADAU
real tim
oad Parameter
s 0x0005 are th
on
ta-word. The re
ich starts at A
AD
written, the ad
te a parameter at A
mber i
r of words to writ
st standard signal processing algorithms
he write addres
x0009.
s the number of words to be
ntrols the modulo RAM size, is
on the dynamic address gen
ad parameter space contains five data
1442/ADAU1445/ADAU1446
s five. For a simple monogain
e while avoiding pop and click
ddress 0x0001. Therefore,
e five data slots for storing
dress increments
s is calculated relative to
ason for the target
RAM Defaults
e/safeload trigger
ddress 0x000A, the
erator
written.
set by
Rev. C | Page 81 of 92
cel
wh
The
per a
when designing the communication protocol. A delay equal to
or greater than the sampling period (the inverse of sampling
frequency) is required between each safeload write. At a
rate of 48 kHz, this equates to a delay of greater than or equal to
20.83 μs. If this delay is not ob
be corrupted.
SOFTWARE SLEW
When the values of signal processing parameters are changed
abruptly in real time, they sometimes cause pop an
to appear on the audio outputs. To avoid this, so e algorithms
in SigmaStudio implement a software slew functio
slew algorithms set a target value for the parame r and contin-
uously update the parameter’s value until it reac s the target.
The target value takes an additional space in param ter RAM, and
the current value of the parameter is updated in
section of data RAM. Assignment of parameters a d nonmodulo
data RAM is handled by the SigmaStudio compi
need to be programmed manually.
Slew parameters can follow several different curves, including an
RC-type curve and a linear curve. These curve types are coded
into each algorithm and cannot be modified by
Because algorithms that use software slew generally require more
RAM than their nonslew equivalents, they should be used only
in situations in which a parameter is expected to chang
operation of the device.
Figure 59 shows an example of a
wave.
l, the number is o
en it is written, a s
safeload mecha
udio frame. Ther
INITIAL VALUE
ADAU1442/ADAU1445/ADAU1446
Figure 59. Example of Volume Slew
nism is software ba
afeload write is tri
ne. This address als
efore, system desig
NEW TARGET
VALUE
served, the downloaded data will
volume slew applied to a sine
ggered on the next frame.
CURVE
SLEW
sed and executes once
o serves as t
ners should take care
nali
he
th
m
ler a
d click s
te
th
e
n
e user.
e nonmodulo
ty. Software
he trigger;
nd does not
e during
ounds
sample