ADAV4601 System Design Document
Confidential Information
Rev.1 August 2009
Analog Devices
Page 48
USING A CUSTOM FLOW WITH THE APPLICATION LAYER
We strongly recommend this approach. The advantage of using the Application Layer is that it automatically takes
care of safeloading. It dramatically reduces the amount of I
2
C writes to the part freeing up the I
2
C bus in your system
and simplifying microcontroller code.
Design custom flow in
SigmaStudio
Link, Compile and generate
params.params file
Store ROMs on an external
EPROM for download to the
ADAV4601
Using params.params file
and Application Layer
Creation Software generate
ROMs and Register Map
to control the custom
flow as desired
Figure 37. Using a Custom Flow with the Application Layer
Custom Flow with Application Layer Example
A general 2
nd
order low pass filter will have a number of filter cut off frequencies and an address defined by the user
in the Application Layer Software. In order to change the cut off frequency simply write to address of the register
and change it to one of the pre-defined cut offs. For this example assume the address is 0x1000 and a cut off of
2kHz is assigned to a value of 0xF, then write required to change the filter cut off is
34 1000 000F
This only requires one I
2
C write compared to the previous example which took eleven I
2
C writes.
ROMS and Registers
When the ADAV4601 is configured for use with the Application Layer it contains four ROMS: program, instruction,
parameter, and LUT. All can be stored externally on an EEPROM and can be loaded after power-up.
Program ROM
Program ROM is
42-bits wide
and occupies
Address 0x1400 to Address 0x1FFF
. This is where the audio flow
generated in SigmaStudio is stored.
Instruction ROM
Instruction ROM is
33-bits wide
and occupies
Address 0x3000 to Address 0x327F
. This is where the application
layer register map is stored.
Parameter ROM
Parameter ROM is
28-bits wide
and occupies
Address 0x1000 to Address 0x13FF
. Default parameters for custom
flow are stored here.
LUT ROM
LUT ROM is
28-bits wide
and occupies
Address 0x4000 to Address 0x57FF
. This contains the remaining
predefined parameters for the custom flow.
Содержание ADAV4601
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