ADAU1445 Analog Devices, ADAU1445 Datasheet - Page 20

• 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

ADAU1442/ADAU1445/ADAU1446
INITIALIZATION
Power-Up Sequence
The ADAU1442/ADAU1445/ADAU1446 have a built-in initiali-
zation period, which allows sufficient time for the PLL to lock
and the registers to initialize their values. On a positive edge of
RESET , the PLL settings are immediately set by the PLL0, PLL1,
and PLL2 pins, and the master clock signal is blocked from the
chip subsystems. The initialization time, which is measured from
the rising edge of RESET , is dependent on the frequency of the
signal input to the XTALI pin, or f
where D is the PLL divider, as set by the PLL0, PLL1, and PLL2
pins. The PLL divider settings are described in Table 9.
For example, if the signal input to XTALI has a frequency of
12.288 MHz and the PLL divider is set to 4 (PLL = 0, PLL1 = 1,
and PLL2 = 0), the initialization time lasts
New values should not be written via the control port until the
initialization is complete.
Table 8 shows some typical times to boot the ADAU1442/
ADAU1445/ADAU1446 into the operational state necessary for an
application, assuming that a 400 kHz I
clock is used and a full program, parameter set, and all registers
(9 kB) are loaded. In reality, most applications use less than this full
amount, and unused program and parameter RAM need not be
initialized; therefore, the total boot time may be shorter.
Recommended Program/Parameter Loading Procedure
When writing large amounts of data to the program or parameter
RAM in direct write mode, such as when downloading the initial
contents of the RAMs from an external memory, the processor core
should be disabled to prevent unpleasant noises from appearing
at the audio output. When small amounts of data are transmitted
during real-time operation of the DSP, such as when updating
individual parameters, the software safeload mechanism can be
used. More information is available in the Software Safeload
section.
Power-Reduction Modes
Sections of the ADAU1442/ADAU1445/ADAU1446 chips can be
turned on and off as needed to reduce power consumption.
Table 8. Power-Up Time
PLL Lock Time (ms)
(f
PLL Divider = 4)
10.667
XTALI
1/(f
1/(12288000/4) × 2
= 12.288 MHz,
XTALI
/D) × 2
15
sec
15
sec = 0.010667 sec (or 10.667 ms)
I
25
2
C (@ 400 kHz SCL)
Approximate Boot Time; Loading Maximum Program/Parameter/Registers (ms)
XTALI
. The total initialization time is
2
C clock or a 5 MHz SPI
SPI (@ 5 MHz CCLK)
2
Rev. C | Page 20 of 92
These include the ASRCs, S/PDIF receiver and transmitter,
auxiliary ADCs, and DSP core. More information is available in
the Master Clock and PLL Modes and Settings section.
System Initialization Sequence
Before the IC can process audio in the DSP, the following initial-
ization sequence must be completed. (Step 5 through Step 11
can be performed in any order, as needed.)
1.
2.
3.
4.
5.
6.
7.
8.
9.
10. Write the program RAM (Address 0x2000 to Address
11. Write the nonmodulo data RAM (Addresses vary based on
12. Write all other necessary control registers, such as ASRCs
13. Set the DSP core rate select register (0xE220) to the desired
14. Assert the core run bit (see the DSP Core Modes and
Power on the IC and bring it out of reset. The order of the
power supplies (DVDD, IOVDD, and AVDD) does not matter.
Wait at least 10.667 ms for the initialization to complete if the
XTALI input is 12.288 MHz and the PLL divider is set to 4
(see the Power-Up Sequence section for information about
calculating the initialization time if another f
Enable the master clocks of all modules to be used (see the
Master Clock and PLL Modes and Settings section).
Set the DSP core rate select register (0xE220) to 0x001C.
This disables the start pulse to the core.
Deassert the core run bit (see the DSP Core Modes and
Settings section).
Set the serial input modes (see the Serial Input Port Modes
Registers (Address 0xE000 to Address 0xE008) section).
Set the serial output modes (see the Serial Output Port
Modes Registers (Address 0xE040 to Address 0xE049)
section).
Set the routing matrix modes (see details of Address 0xE080
to Address 0xE09B in the Flexible Audio Routing Matrix
Modes section).
Write the parameter RAM (Address 0x0000 to Address
0x0FFF).
0x2FFF).
the SigmaStudio project file).
and S/PDIF (Address 0xE221 to Address 0xE24C).
value. This enables the start pulse to the core. Table 12
contains a list of valid settings.
Settings section).
SPI (@ 25 MHz CCLK)
0.4
Total (ms)
11.067 to 35.667
XTALI
is used).