ANALOG DEVICES AN-1050 Service Manual
AN-1050
APPLICATON NOTE
One Technology Way • P. O . Box 9106 • Norwood, MA 02062-9106, U.S.A. • Tel : 781.329.4700 • Fax : 781.461.3113 • www.analog.com
2
A Method for Compressing I
C Scripts for the
ADV74xx/AD V78xx V75xx/ADV76xx/AD
by Witold Kaczurba
INTRODUCTION
This application note describes a method for compressing larg
2
sets of I
ation herein is targeted for applications where the user needs to
put over 50 scripts to the memory of one single microcon
This method provides excellent results for sets of scripts
containing m
an I C bus.
Analog Devices, Inc., multiformat decoders allow users
decode various standards of video. Because a variety of
standards are supported, these video decoders provide various
settings. Each setting contains the bulk of I
mode. These writes are collected as scripts.
In some cases, the user may use hundreds of scripts to conf
many I
C scripts for microcontroller platforms. The inform-
ore than 200 scripts for more than six devices on
2
2
C
writes for each
2
C devices. In such a case, the user requires a lot of
TEXT FILE:
2
SET OF I
C SCRIPTS
troller.
to
igure
COMPRESSING
Figure 1. Concept of Compressing Algorithms
e
OCTAVE
SCRIPT
memory in a small microcontroller to keep all of these scripts.
Note that these scripts may have similar writes as well as unique
writes. This application note details how to compress the script
on the PC side, as well as how to write an efficient decompress
sing method on the microcontroller side. The decompressing
algorithm utilizes more efficient functions requiring less RAM.
This application note includes a script for an Octave program.
Octave is a free
(GNU/GPL license) computer program for
numerical computations. This Octave script can compress
scripts and export the results to the C code with decompressi
procedures. The resulting C code
p
ortable to any microcontroller.
is easy to use, and is easily
ng
C-CODE:
-COMPRESSED SCRIPT
R-DECOMPRESSO
8522-001
-
Rev. 0 | Page 1 of 20
AN-1050 Application Note
TABLE OF CONTENTS
Introduction ...................................................................................... 1
About the Scripts .............................................................................. 3
Basic Knowledge ........................................................................... 3
Construction of the Script ........................................................... 3
Compression/Decompression..................................................... 6
Usage .............................................................................................. 7
Octave Source Code ......................................................................... 8
main.m ........................................................................................... 8
load_script.m .............................................................................. 10
number_of_scripts_in_file.m ................................................... 11
fsubst.m ........................................................................................ 12
find_mat2.m ................................................................................ 12
script_to_c.m .............................................................................. 13
Conclusion....................................................................................... 19
Results .......................................................................................... 19
Further Optimizations ............................................................... 19
References and Licensing Information .................................... 19
Rev. 0 | Page 2 of 20
Application Note AN-1050
ABOUT THE SCRIPTS
BASIC KNOWLEDGE
The compression method described in this application note is
intended to be used with sets of scripts constructed as shown in
the Construction of the Script section. One I
three values:
• device address (to address the device on the I
• register address
• value to be written to the register
Usually scripts provided with evaluation boards by Analog
Devices use ascending order by I
2
C writes. This means that
writes to the same device are in ascending order of register
addresses, such as:
• 42 00 AB
• 42 01 CD
• 42 02 EF
This not accidential; the order of writes makes compression
more efficient because it is more likely to find the same pattern
across various scripts. Note that it is unlikely to find the same
write to the same register of the same device, such as:
• 42 03 04
• 42 03 08
This increases the probability of the same sequences of writes
occurring in different scripts. This is why this application
note describes algorithms in which scripts are checked for
occurrence of sequences of four identical writes, as shown in
Figure 2.
##SCRIPT##
:SCRIPT 1:
42 03 04;
42 04 06;
42 0A 53;
42 0C 23;
42 0F 45;
42 22 39;
42 AA 10;
42 FF 03;
...
Figure 2. Sequence of Four Identical Writes Occurs in Two Different Scripts
##SCRIPT##
:SCRIPT 2:
42 00 03;
42 02 27;
42 03 09;
42 04 FF;
42 0A 53;
42 0C 23;
42 0F 45;
42 22 39;
42 FF 02;
...
2
C write consists of
2
C bus)
08522-002
Storing large sequences (of four writes) that are common for
various script big blocks is beneficial to the microcontroller
side. These common blocks (also called keys) can be stored as
a continuous array in a C program. Thus, each key is easily
addressable. This ease of addressing the keys eliminates many
pointers that would otherwise have to be used in the decompresssing algorithm. Each constant pointer requires memory.
CONSTRUCTION OF THE SCRIPT
The Octave script that is used for compression requires an
original set of scripts to be stored in a file in a particular way.
Each original script starts with a header (the first line) containing the characters ## at both the beginning and the end of the
line. The next line in the script is a small header that must
contain colons at both the beginning and at the end of the line.
The following line, the third line, contains proper I
such as:
42 05 02 ; Prim_Mode = 010b for GR
where:
42 indicates the device’s 8-bit, I
2
C address (0x42).
05 is the 8-bit, register address (0x05).
02 is the 8-bit value (0x02).
Prim_Mode = 010b for GR is an optional, user-defined
comment.
Note the spaces and semicolon in the equation. The last line of
the script is single word End, without any spaces. Scripts are
split by the use of empty lines.
The following pages provide an example portion of the set of scripts
for the ADV7401 evaluation board (EVAL-ADV7401EBZ).
2
C writes,
Rev. 0 | Page 3 of 20
AN-1050 Application Note
##CP VGA 640x480##
:640x480 _@ 60 Autodetecting sync source 25.175 MHz out through DAC:
42 05 02 ; Prim_Mode = 010b for GR
42 06 08 ; VID_STD = 1000b for 640 × 480 @ 60
42 1D 47 ; Enable 28 MHz crystal
42 3A 11 ; Set latch clock settings to 001b, Power down ADC3
42 3B 80 ; Enable external bias
42 3C 5C ; PLL_QPUMP to 100b
42 6A 00 ; DLL phase adjust
42 6B 82 ; Enable DE output, swap Pr& Pb
42 73 90 ; Set man_gain
42 7B 1D ; TURN OFF EAV & SAV CODES Set BLANK_RGB_SEL
42 85 03 ; Enable DS_OUT
42 86 0B ; Enable stdi_line_count_mode
42 8A 90 ; VCO range to 00b
42 F4 3F ; Max drive strength
42 0E 80 ; Analog Devices recommended setting
42 52 46 ; Analog Devices recommended setting
42 54 00 ; Analog Devices recommended setting
42 0E 00 ; Analog Devices recommended setting
54 00 13 ; Power-down encoder
74 EE EE ; Power-down HDMI
End
##CP VGA 640x480##
:640x480 _@ 72 Autodetecting sync source 31.5 MHz out through DAC:
42 05 02 ; Prim_Mode = 010b for GR
42 06 09 ; VID_STD = 1001b for 640 × 480 @ 72
42 1D 47 ; Enable 28 MHz crystal
42 3A 11 ; set latch clock settings to 001b, Power down ADC3
42 3B 80 ; Enable external bias
42 3C 5C ; PLL_QPUMP to 100b
42 6A 00 ; DLL phase adjust
42 6B 82 ; Enable DE output, swap Pr& Pb
42 73 90 ; Set man_gain
42 7B 1D ; TURN OFF EAV & SAV CODES Set BLANK_RGB_SEL
42 85 03 ; Enable DS_OUT
42 86 0B ; Enable stdi_line_count_mode
42 F4 3F ; Max drive strength
42 0E 80 ; Analog Devices recommended setting
42 52 46 ; Analog Devices recommended setting
42 54 00 ; Analog Devices recommended setting
42 0E 00 ; Analog Devices recommended setting
54 00 13 ; Power down encoder
74 EE EE ; Power down HDMI
End
Rev. 0 | Page 4 of 20
Application Note AN-1050
##CP VGA 640x480##
:640x480 _@ 75 Autodetecting sync source 31.5 MHz Out through DAC:
42 05 02 ; Prim_Mode = 010b for GR
42 06 0A ; VID_STD =1 010b for 640 × 480 @ 75
42 1D 47 ; Enable 28 MHz crystal
42 3A 11 ; set latch clock settings to 001b, Power down ADC3
42 3B 80 ; Enable external bias
42 3C 5C ; PLL_QPUMP to 100b
42 6A 00 ; DLL phase adjust
42 6B 82 ; Enable DE output, swap Pr& Pb
42 73 90 ; Set man_gain
42 7B 1D ; TURN OFF EAV & SAV CODES Set BLANK_RGB_SEL
42 85 03 ; Enable DS_OUT
42 86 0B ; Enable stdi_line_count_mode
42 F4 3F ; Max drive strength
42 0E 80 ; Analog Devices recommended setting
42 52 46 ; Analog Devices recommended setting
42 54 00 ; Analog Devices recommended setting
42 0E 00 ; Analog Devices recommended setting
54 00 13 ; Power down encoder
74 EE EE ; Power down HDMI
End
Rev. 0 | Page 5 of 20
AN-1050 Application Note
Note that the device address used in the scripts is always an
even number greater than 0. Odd addresses are used for reading
back from the device, which does not occur in this case. Thus,
Address 0x00 is used as an escape code, a special code used for
decompressing.
COMPRESSION/DECOMPRESSION
The Octave script in the Octave Source Code section compresses the script on the PC side. An output of Octave script
is C code containing compressed data and the decompression
algorithm.
The Octave script algorithm consists of the following steps:
1. The script is loaded into matrices of various dimensions
(size is dependent on length of script).
2. The matrices are searched for common blocks or keys
where each key consists of four writes.
0x00, 0x00, 0x09
0x42, 0x3A, 0x13
0x00, 0x00, 0x01
0x42, 0x69, 0x03
0x42, 0x86, 0x0B
0x42, 0xF3, 0x03
0x00, 0x00, 0x02
0x00, 0x00, 0x03
0x00, 0x00, 0x04
0x00, 0x00, 0x0A
0x54, 0x87, 0x20
0x74, 0xFC, 0xFC
COMPRESSED SCRI P T
9TH KEY
ST
1
ND
2
RD
3
TH
4
TH
10
KEYS ARE SHARED BETW E EN
COMPRESSED SCRI P TS
0x42, 0x03, 0x0C
0x42, 0x04, 0x57
0x42, 0x1D, 0x47
0x42, 0x31, 0x02
KEY
KEY
KEY
KEY
KEY
0x42, 0x3B, 0x80
0x42, 0x3D, 0xA2
0x42, 0x3E, 0x6A
0x42, 0x3F, 0xA0
0x42, 0xF9, 0x03
0x42, 0x0E, 0x80
0x42, 0x52, 0x46
0x42, 0x54, 0x00
0x42, 0x7F, 0xFF
0x42, 0x81, 0x30
0x42, 0x90, 0xC9
0x42, 0x91, 0x40
0x42, 0x92, 0x3C
0x42, 0x93, 0xCA
0x42, 0x94, 0xD5
0x42, 0xB1, 0xFF
0x00, 0x00, 0x05
0x00, 0x00, 0x06
0x00, 0x00, 0x07
0x00, 0x00, 0x08
Figure 3. Structure of Compressed Scripts
3. If a common block is found, it is written to a separate block
called keys with a key_number index.
4. Where there is a common block, the block is replaced with
a single write: (0x00, A, B) where A × 256 + B is a value
key_number.
5. The key_number index is increased by one.
6. Finding and replacing the common blocks is repeated until
a search from beginning to end produces no results.
This process creates the structure of matrices as shown in
Figure 3.
KEYS ARE SHARED BETWEEN
5TH KEY
TH
6
TH
7
TH
8
COMPRESSED SCRI P TS
0x42, 0xB6, 0x08
0x42, 0xC0, 0x9A
0x42, 0xCF, 0x50
0x42, 0xD0, 0x4E
KEY
0x42, 0xD1, 0xB9
0x42, 0xD6, 0xDD
0x42, 0xD7, 0xE2
0x42, 0xE5, 0x51
KEY
0x42, 0x0E, 0x00
0x54, 0x17, 0x02
0x54, 0x00, 0xFC
0x54, 0x01, 0x80
KEY
0x54, 0x80, 0x10
0x54, 0x82, 0xC9
0x54, 0x84, 0x06
0x54, 0x88, 0x00
08522-003
Rev. 0 | Page 6 of 20
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