GENNUM GS4901B_09

GS4901B/GS4900B SD Clock and Timing Generator with GENLOCK
Key Features
Description
Video Clock Synthesis
•
•
•
•
•
Pre-programmed for 4 video clock periods (14.32 MHz, 27
MHz, 36 MHz, and 54 MHz)
Accuracy of free-running clock frequency limited only by
crystal reference
One differential and two single-ended video clock outputs
Each clock may be individually delayed for skew control
Video output clock may be directly connected to Gennum’s
serializers for a SMPTE-compliant SDI output
Audio Clock Synthesis (GS4901B only)
•
•
•
Three audio clock outputs
Generates any audio clock up to 512*96kHz
Pre-programmed for 7 audio clocks
Timing Generation
•
•
•
Generates up to 8 timing signals at a time
Choose from 9 pre-programmed timing signals: H and V sync
and blanking, F Sync, F Digital, AFS (GS4901B only), Display
Enable, 10FID, and up to 4 user-defined timing signals
Pre-programmed to generate timing for 9 different video
formats
Genlock Capability
•
•
•
•
•
•
Clocks may be free-running or genlocked to an input
reference with a variable offset step size of 100-200ps
(depending on exact clock frequency)
Variable timing offset step size of 100-200ps up to one frame
Output may be cross-locked to a different input reference
Freeze operation on loss of reference
Optional crash or drift lock on application of reference
Automatic input format detection
General Features
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•
•
•
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Reduces design complexity and saves board space - 9mm x
9mm package plus crystal reference replaces multiple
VCXOs, PLLs and timing generators
Pb-free and RoHS Compliant
Low power operation typically 300mW
1.8V core and 1.8V or 3.3V I/O power supplies
64-PIN QFN package
Applications
•
Video cameras; Digital audio and/or video recording/play
back devices; Digital audio and/or video processing devices;
Computer/video displays; DVD/MPEG devices; Digital Set
top boxes; Video projectors; High definition video systems;
Multi-media PC applications
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
The GS4901B is a highly flexible, digitally controlled clock
synthesis circuit and timing generator with genlock
capability. It can be used to generate video and audio
clocks and timing signals, and allows multiple devices to be
genlocked to an input reference.
The GS4900B includes all the features of the GS4901B, but
does not offer audio clocks or AFS pulse generation.
The GS4901B/GS4900B will recognize input reference
signals conforming to 36 different video standards, and will
genlock the output timing information to the incoming
reference. The GS4901B/GS4900B supports cross-locking,
allowing the output to be genlocked to an incoming
reference that is different from the output video standard
selected.
The user may select to output one of 4 different video
sample clock rates. The chosen clock frequency can be
further divided using internal dividers, and is available on
two video clock outputs and one LVDS video clock output
pair. The video clocks are frequency and phased-locked to
the horizontal timing reference, and can be individually
delayed with respect to the timing outputs for clock skew
control.
Eight user-selectable timing outputs are provided that can
automatically produce the following timing signals for 9
different video formats: HSync, Hblanking, VSync,
Vblanking, F sync, F digital, AFS (GS4901B only), DE, and
10FID. These timing outputs may be locked to the input
reference signal for genlock timing and may be phase
adjusted via internal registers.
In addition, the GS4901B provides three audio sample
clock outputs that can produce audio clocks up to 512fs
with fs ranging from 9.7kHz to 96kHz. Audio to video
phasing is accomplished by an external 10FID input
reference, a 10FID signal specified via internal registers, or
a user-programmed audio frame sequence.
The GS4901B/GS4900B is Pb-free, and the encapsulation
compound does not contain halogenated flame retardant
(RoHS Compliant).
www.gennum.com
1 of 102
LOCK_LOST
VID_STD[5:0]
GENLOCK
ASR_SEL[2:0]
X1
X2
user[4:1]
27MHz
Input Reference
Rate Identification
and Control
ref_rate
REF_LOST
Flywheel and Video
Timing Generator
AFS
10FID
DE
F digital
F sync
V blanking
V sync
TIMING_OUT_8
TIMING_OUT_7
TIMING_OUT_6
Crosspoint
TIMING_OUT_4
TIMING_OUT_3
TIMING_OUT_2
H blanking
H sync
Clock Synthesis
and Control
TIMING_OUT_5
TIMING_OUT_1
PCLK1
Clock
Phase
Adjust
pclk
Video Clock
Divide
3x Video Clock
Delay Adjust
PCLK2
PCLK3
PCLK3
aclk_512
aclk_384
Audio Clock
Divide
ACLK1
ACLK2
ACLK3
HSYNC
VSYNC
FSYNC
10FID
CS_TMS
SDIN_TDI
SDOUT_TDO
SCLK_TCLK
JTAG/HOST
Application Programming Interace
GS4901B Functional Block Diagram
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
2 of 102
LOCK_LOST
VID_STD[5:0]
GENLOCK
X1
X2
user[4:1]
27MHz
Input Reference
Rate Identification
and Control
ref_rate
REF_LOST
Flywheel and Video
Timing Generator
10FID
DE
F digital
F sync
V blanking
V sync
TIMING_OUT_8
TIMING_OUT_7
TIMING_OUT_6
Crosspoint
TIMING_OUT_2
TIMING_OUT_1
Clock Synthesis
and Control
pclk
Video Clock
Divide
TIMING_OUT_4
TIMING_OUT_3
H blanking
H sync
Clock
Phase
Adjust
TIMING_OUT_5
PCLK1
3x Video Clock
Delay Adjust
PCLK2
PCLK3
PCLK3
HSYNC
VSYNC
FSYNC
10FID
CS_TMS
SDIN_TDI
SDOUT_TDO
SCLK_TCLK
JTAG/HOST
Application Programming Interace
GS4900B Functional Block Diagram
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
3 of 102
Contents
Key Features........................................................................................................................................................1
Applications.........................................................................................................................................................1
Description...........................................................................................................................................................1
1. Pin Out...............................................................................................................................................................7
1.1 GS4901B Pin Assignment ...............................................................................................................7
1.2 GS4900B Pin Assignment ...............................................................................................................8
1.3 Pin Descriptions ................................................................................................................................9
1.4 Pre-Programmed Recognized Video Standards .................................................................. 19
1.5 Output Timing Signals ................................................................................................................. 23
2. Electrical Characteristics ......................................................................................................................... 27
2.1 Absolute Maximum Ratings ....................................................................................................... 27
2.2 DC Electrical Characteristics ..................................................................................................... 27
2.3 AC Electrical Characteristics ..................................................................................................... 31
2.4 Solder Reflow Profiles .................................................................................................................. 34
3. Detailed Description.................................................................................................................................. 35
3.1 Functional Overview .................................................................................................................... 35
3.2 Modes of Operation ...................................................................................................................... 35
3.2.1 Genlock Mode..................................................................................................................... 35
3.2.2 Free Run Mode ................................................................................................................... 39
3.3 Output Timing Format Selection .............................................................................................. 40
3.4 Input Reference Signals ............................................................................................................... 41
3.4.1 HSYNC, VSYNC, and FSYNC.......................................................................................... 41
3.4.2 10FID ..................................................................................................................................... 42
3.4.3 Automatic Polarity Recognition ................................................................................... 42
3.5 Reference Format Detector ........................................................................................................ 43
3.5.1 Horizontal and Vertical Timing Characteristic Measurements ......................... 43
3.5.2 Input Reference Validity................................................................................................. 44
3.5.3 Behaviour on Loss and Re-acquisition of the Reference Signal......................... 45
3.5.4 Allowable Frequency Drift on the Reference .......................................................... 47
3.6 Genlock ............................................................................................................................................. 47
3.6.1 Adjustable Locking Time................................................................................................. 49
3.6.2 Adjustable Loop Bandwidth .......................................................................................... 49
3.6.3 Locking to Digital Timing from a Deserializer ......................................................... 52
3.7 Clock Synthesis .............................................................................................................................. 52
3.7.1 Video Clock Synthesis...................................................................................................... 52
3.7.2 Audio Clock Synthesis (GS4901B only)...................................................................... 54
3.8 Video Timing Generator .............................................................................................................. 58
3.8.1 10 Field ID Pulse................................................................................................................. 58
3.8.2 Audio Frame Synchronizing Pulse (GS4901B only)............................................... 59
3.8.3 USER_1~4 ............................................................................................................................. 60
3.8.4 TIMING_OUT Pins ............................................................................................................. 62
3.9 Extended Audio Mode for HD Demux using the Gennum Audio Core ...................... 63
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
4 of 102
3.10 GSPI Host Interface ..................................................................................................................... 64
3.10.1 Command Word Description ...................................................................................... 66
3.10.2 Data Read and Write Timing ....................................................................................... 66
3.10.3 Configuration and Status Registers........................................................................... 67
3.11 JTAG ................................................................................................................................................. 93
3.12 Device Power-Up ........................................................................................................................ 94
3.12.1 Power Supply Sequencing ........................................................................................... 94
3.13 Device Reset .................................................................................................................................. 94
4. Application Reference Design ............................................................................................................... 95
4.1 GS4901B Typical Application Circuit ..................................................................................... 95
4.2 GS4900B Typical Application Circuit ..................................................................................... 96
5. References & Relevant Standards ......................................................................................................... 97
6. Package & Ordering Information .......................................................................................................... 98
6.1 Package Dimensions ..................................................................................................................... 98
6.2 Recommended PCB Footprint ................................................................................................... 99
6.3 Packaging Data ............................................................................................................................... 99
6.4 Ordering Information ................................................................................................................. 100
7. Revision History........................................................................................................................................ 101
List of Figures
GS4901B Functional Block Diagram ......................................................................................................... 2
GS4900B Functional Block Diagram ......................................................................................................... 3
Figure 1-1: XTAL1 and XTAL2 Reference Circuits .............................................................................. 18
Figure 2-1: PCLK to TIMING_OUT Signal Output Timing ................................................................. 32
Figure 2-2: Maximum Pb-free Solder Reflow Profile (preferred) .................................................. 34
Figure 2-3: Standard Pb Solder Reflow Profile .................................................................................... 34
Figure 3-1: SD-HD Calculation .................................................................................................................. 38
Figure 3-2: Output Accuracy and Modes of Operation ..................................................................... 40
Figure 3-3: Example HSYNC, VSYNC, and FSYNC Analog Input Timing from a
Sync Separator ................................................................................................................................................ 41
Figure 3-4: Example H Blanking, V Blanking, and F Digital Input Timing from an
SDI Deserializer .............................................................................................................................................. 41
Figure 3-5: 10FID Input Timing ................................................................................................................. 42
Figure 3-6: Default 10FID Output Timing .............................................................................................. 58
Figure 3-7: Optional 10FID Output Timing ........................................................................................... 59
Figure 3-8: AFS Output Timing ................................................................................................................. 60
Figure 3-9: USER Programmable Output Signal .................................................................................. 61
Figure 3-10: Audio Clock Block Diagram for HD Demux Operation ........................................... 64
Figure 3-11: GSPI Application Interface Connection ........................................................................ 65
Figure 3-12: Command Word Format ..................................................................................................... 66
Figure 3-13: Data Word Format ................................................................................................................ 66
Figure 3-14: GSPI Read Mode Timing ..................................................................................................... 67
Figure 3-15: GSPI Write Mode Timing .................................................................................................... 67
Figure 3-16: In-Circuit JTAG ...................................................................................................................... 93
Figure 3-17: System JTAG ........................................................................................................................... 94
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
5 of 102
List of Tables
Table 1-1: Pin Descriptions ............................................................................................................................ 9
Table 1-2: Recognized Video Standards................................................................................................. 20
Table 1-3: Output Timing Signals ............................................................................................................. 23
Table 2-1: DC Electrical Characteristics ................................................................................................. 27
Table 2-2: AC Electrical Characteristics ................................................................................................. 31
Table 2-3: Suggested External Crystal Specification ......................................................................... 33
Table 3-1: Clock_Phase_Offset [15:0] Encoding Scheme.................................................................. 37
Table 3-2: Ambiguous Standard Identification.................................................................................... 45
Table 3-3: Max_Ref_Delta Encoding Scheme....................................................................................... 47
Table 3-4: Cross-reference Genlock Table............................................................................................. 48
Table 3-5: Integer Constant Value............................................................................................................ 51
Table 3-6: Video Clock Phase Adjustment Host Settings.................................................................. 54
Table 3-7: Audio Sample Rate Select....................................................................................................... 55
Table 3-8: Audio Clock Divider ................................................................................................................. 55
Table 3-9: Encoding Scheme for AFS_Reset_Window ...................................................................... 56
Table 3-10: Audio Sampling Frequency to Video Frame Rate Synchronization...................... 57
Table 3-11: Crosspoint Select..................................................................................................................... 62
Table 3-12: GSPI Timing Parameters ....................................................................................................... 66
Table 3-13: Configuration and Status Registers................................................................................... 68
Table 5-1: References & Relevant Standards ........................................................................................ 97
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
6 of 102
1. Pin Out
LOCK_LOST
REF_LOST
1
PCLK2
PCLK1
IO_VDD
PCLK1&2_GND
PhS_VDD
PCLK1&2_VDD
JTAG/HOST
PhS_GND
SDIN_TDI
SCLK_TCLK
SDOUT_TDO
RESET
CS_TMS
IO_VDD
GENLOCK
NC
1.1 GS4901B Pin Assignment
64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49
48
LVDS/PCLK3_GND
2
47
PCLK3
VID_PLL_VDD
3
46
PCLK3
VID_PLL_GND
4
45
LVDS/PCLK3_VDD
XTAL_VDD
5
44
X1
6
43
CORE_VDD
TIMING_OUT_8
42
TIMING_OUT_7
41
40
TIMING_OUT_6
TIMING_OUT_5
X2
7
XTAL_GND
8
CORE_GND
GS4901B
64-pin QFN
(Top View)
9
ANALOG_VDD
NC
10
39
TIMING_OUT_4
11
38
IO_VDD
ANALOG_GND
12
37
TIMING_OUT_3
AUD_PLL_GND
13
36
TIMING_OUT_2
AUD_PLL_VDD
14
35
TIMING_OUT_1
10FID
HSYNC
34
15
16
33
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
ASR_SEL0
ASR_SEL1
ASR_SEL2
IO_VDD
ACLK3
ACLK2
ACLK1
VID_STD5
CORE_VDD
VID_STD4
VID_STD3
VID_STD2
VID_STD1
VID_STD0
NC
FSYNC
IO_VDD
VSYNC
Ground Pad
(bottom of package)
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
7 of 102
LOCK_LOST
REF_LOST
1
PCLK2
PCLK1
IO_VDD
PCLK1&2_GND
PhS_VDD
PCLK1&2_VDD
JTAG/HOST
PhS_GND
SDIN_TDI
SCLK_TCLK
SDOUT_TDO
RESET
CS_TMS
IO_VDD
GENLOCK
NC
1.2 GS4900B Pin Assignment
64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49
48
LVDS/PCLK3_GND
2
47
PCLK3
VID_PLL_VDD
3
46
PCLK3
VID_PLL_GND
4
45
LVDS/PCLK3_VDD
XTAL_VDD
5
44
X1
6
43
CORE_VDD
TIMING_OUT_8
X2
7
42
TIMING_OUT_7
41
40
TIMING_OUT_6
TIMING_OUT_5
XTAL_GND
CORE_GND
GS4900B
64-pin QFN
(Top View)
8
9
ANALOG_VDD
NC
10
39
TIMING_OUT_4
11
38
IO_VDD
ANALOG_GND
12
37
TIMING_OUT_3
ANALOG_GND
ANALOG_GND
10FID
13
36
TIMING_OUT_2
14
35
TIMING_OUT_1
34
15
16
33
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
ANALOG_GND
HSYNC
ANALOG_GND
ANALOG_GND
IO_VDD
NC
NC
NC
VID_STD5
CORE_VDD
VID_STD4
VID_STD3
VID_STD2
VID_STD1
VID_STD0
NC
FSYNC
IO_VDD
VSYNC
Ground Pad
(bottom of package)
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
8 of 102
1.3 Pin Descriptions
Table 1-1: Pin Descriptions
Pin
Number
1
Name
Timing
Type
Description
LOCK_LOST
Non
Synchronous
Output
STATUS SIGNAL OUTPUT
Signal levels are LVCMOS/LVTTL compatible.
This pin will be HIGH if the output is not genlocked to the input.
The GS4901B/GS4900B monitors the output pixel/line counters, as
well as the internal lock status from the genlock block and asserts
LOCK_LOST HIGH if it is determined that the output is not
genlocked to the input. This pin will be LOW if the device
successfully genlocks the output clock and timing signals to the
input reference.
If LOCK_LOST is LOW, the reference timing generator outputs will
be phase locked to the detected reference signal, producing an
output in accordance with the video standard selected by the
VID_STD[5:0] pins.
2
REF_LOST
Non
Synchronous
Output
STATUS SIGNAL OUTPUT
Signal levels are LVCMOS/LVTTL compatible.
This pin will be HIGH if:
• No input reference signal is applied to the device; or
• The input reference applied does not meet the
minimum/maximum timing requirements described in
Section 3.5.2 on page 44.
This pin will be LOW otherwise.
If the reference signal is removed when the device is in Genlock
mode, REF_LOST will go HIGH and the GS4901B/GS4900B will enter
Freeze mode (see Section 3.2.1.2 on page 39).
3
VID_PLL_VDD
–
Power
Supply
Most positive power supply connection for the video clock synthesis
internal block. Connect to +1.8V DC.
4
VID_PLL_GND
–
Power
Supply
Ground connection for the video clock synthesis internal block.
Connect to GND.
5
XTAL_VDD
–
Power
Supply
Most positive power supply connection for the crystal buffer.
Connect to either +1.8V DC or +3.3V DC.
NOTE: Connect to +3.3V for minimum output PCLK jitter.
6
7
8
X1
X2
XTAL_GND
Non
Synchronous
Input
Non
Synchronous
Output
–
Power
Supply
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
ANALOG SIGNAL INPUT
Connect to a 27MHz crystal or a 27MHz external clock source. See
Figure 1-1.
ANALOG SIGNAL OUTPUT
Connect to a 27MHz crystal, or leave this pin open circuit if an
external clock source is applied to pin 6. See Figure 1-1.
Ground connection for the crystal buffer. Connect to GND.
9 of 102
Table 1-1: Pin Descriptions (Continued)
Pin
Number
9
Name
Timing
Type
Description
CORE_GND
–
Power
Supply
Ground connection for core and I/O. Solder to the ground plane of
the application board.
NOTE: The CORE_GND pin should be soldered to the same main
ground plane as the exposed ground pad on the bottom of the
device.
10
ANALOG_VDD
–
Power
Supply
Most positive power supply connection for the analog input block.
Connect to +1.8V DC.
NC
–
–
Do not connect.
12
ANALOG_GND
–
Power
Supply
Ground connection for the analog input block. Connect to GND.
13
AUD_PLL_GND
(GS4901B only)
–
Power
Supply
Ground connection for the audio clock synthesis internal block.
Connect to GND.
ANALOG_GND
(GS4900B only)
–
Power
Supply
Ground connection for the analog input block. Connect to GND.
AUD_PLL_VDD
(GS4901B only)
–
Power
Supply
Most positive power supply connection for the audio clock synthesis
internal block. Connect to +1.8V DC.
ANALOG_GND
(GS4900B only)
–
Power
Supply
Ground connection for the analog input block. Connect to GND.
10FID
Non
Synchronous
Input
REFERENCE SIGNAL INPUT
Signal levels are LVCMOS/LVTTL compatible.
11, 20, 63
14
15
The 10FID external reference signal is applied to this pin by the
application layer. 10FID defines the field in which the video and
audio clock phase relationship is defined according to SMPTE
318-M. It is also used to define a 3:2 video cadence.
NOTE: If the input reference format does not include a 10 Field ID
signal, this pin should be held LOW. See Section 3.4.2 on page 42.
16
HSYNC
Non
Synchronous
Input
REFERENCE SIGNAL INPUT
Signal levels are LVCMOS/LVTTL compatible.
The HSYNC external reference signal is applied to this pin by the
application layer. When the GS4901B/GS4900B is operating in
Genlock mode, the device senses the polarity of the HSYNC input
automatically, and references to the leading edge.
This signal must adhere to one of the 36 defined video standards
supported by the device. In this mode of operation, the HSYNC
input provides a horizontal scanning reference signal.
The HSYNC signal may have analog timing, such as from a sync
separator, or may be digital such as from an SDI deserializer.
Section 1.4 on page 19 describes the 36 video formats recognized by
the GS4901B/GS4900B.
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
10 of 102
Table 1-1: Pin Descriptions (Continued)
Pin
Number
17
Name
Timing
Type
Description
VSYNC
Non
Synchronous
Input
REFERENCE SIGNAL INPUT
Signal levels are LVCMOS/LVTTL compatible.
The VSYNC external reference signal is applied to this pin by the
application layer. When the GS4901B/GS4900B is operating in
Genlock mode, the device senses the polarity of the VSYNC input
automatically, and references to the leading edge.
This signal must adhere to one of the 36 defined video standards
supported by the device. In this mode of operation, the VSYNC
input provides a vertical scanning reference signal.
The VSYNC signal may have analog timing, such as from a sync
separator, or may be digital such as from an SDI deserializer.
Section 1.4 on page 19 describes the 36 video formats recognized by
the GS4901B/GS4900B.
18, 31, 38,
50, 62
IO_VDD
–
Power
Supply
Most positive power supply connection for the digital I/O signals.
Connect to either +1.8V DC or +3.3V DC.
NOTE: All five IO_VDD pins must be powered by the same voltage.
19
FSYNC
Non
Synchronous
Input
REFERENCE SIGNAL INPUT
Signal levels are LVCMOS/LVTTL compatible.
The FSYNC external reference signal is applied to this pin by the
application layer.
The first field is defined as the field in which the first broad pulse
(also known as serration) is in the first half of a line. The FSYNC
signal should be set HIGH during the first field for sync-based
references.
Then this signal must adhere to one of the 36 defined video
standards supported by the device. In this mode of operation, the
FSYNC input provides an odd/even field input reference.
The FSYNC signal may have analog timing, such as from a sync
separator, or may be digital such as from an SDI deserializer.
Section 1.4 on page 19 describes the 36 video formats recognized by
the GS4901B/GS4900B.
For blanking-based references, the FSYNC signal should be set HIGH
during the second field.
NOTE: If the input reference format does not include an F sync
signal, this pin should be held LOW.
27, 25, 24,
23, 22, 21
VID_STD[5:0]
Non
Synchronous
Input
CONTROL SIGNAL INPUTS
Signal levels are LVCMOS/LVTTL compatible.
Video Standard Select.
Used to select the desired video format for video clock and timing
signal generation.
4 different video sample clocks, as well as 9 different video format
timing signal outputs may be selected using these pins.
NOTE: The VID_STD[5:4] pins should be grounded by the application
layer since these pins are not required to select output video
standards 1 to 10.
For details on the supported video standards and video clock
frequency selection, please see Section 1.4 on page 19.
26, 44
CORE_VDD
–
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
Power
Supply
Most positive power supply connection for the digital core. Connect
to +1.8V DC.
11 of 102
Table 1-1: Pin Descriptions (Continued)
Pin
Number
28, 29, 30
Name
Timing
Type
Description
ACLK1
–
Output
CLOCK SIGNAL OUTPUTS
Signal levels are LVCMOS/LVTTL compatible.
ACLK2
ACLK3
Audio output clock signals.
(GS4901B only)
ACLK1, ACLK2, and ACLK3 present audio sample rate clock outputs
to the application layer.
By default, after system reset, the audio clock output pins of the
device provide clock signals as follows:
ACLK1 = 256fs
ACLK2 = 64fs
ACLK3 = fs, where fs is the fundamental sampling frequency.
The fundamental sampling frequency is selected using
ASR_SEL[2:0]. Additional sampling frequencies may be programmed
in the host interface.
It is also possible to select different division ratios for each of the
audio clock outputs by programming designated registers in the
host interface. Clock outputs of 512fs, 384fs, 256fs, 192fs, 128fs,
64fs, fs and z bit are selectable on a pin-by-pin basis.
NOTE: ACLK1-3 will have a 50% duty cycle, unless fs is selected as
96kHz and the host interface is configured such that one of the
three ACLK pins is set to output a clock signal at 192fs or 384fs. If
this is the case, then a 512fs clock will have a 33% duty cycle.
These signals will be high impedance when ASR_SEL[2:0] = 000b.
32, 33, 34
NC
(GS4900B only)
–
–
Do not connect.
ASR_SEL[2:0]
Non
Synchronous
Input
CONTROL SIGNAL INPUTS
Signal levels are LVCMOS/LVTTL compatible.
(GS4901B only)
Audio Sample Rate Select.
Used to select the fundamental sampling frequency, fs, of the audio
clock outputs. See Table 3-7.
When ASR_SEL[2:0] = 000b, audio clock generation will be disabled
and the ACLK1 to ACLK3 pins will be high impedance. In this case,
AUD_PLL_VDD (pin 14) may be connected to GND to minimize noise
and power consumption.
35
ANALOG_GND
(GS4900B only)
–
Power
Supply
Ground connection for the analog input block. Connect to GND.
TIMING_OUT_1
Synchronous
with PCLK1
~ PCLK3
Output
TIMING SIGNAL OUTPUT
Signal levels are LVCMOS/LVTTL compatible.
Selectable timing output.
Selectable from: H sync; H blanking; V sync; V blanking; F sync; F
digital; Display Enable; 10 field ID (film cadence); AFS video/audio
timing (GS4901B only); USER_1~4.
See Section 1.5 on page 23 for signal descriptions.
NOTE: Default output is H Sync.
The current drive capability of this pin may be set high or low via
designated registers in the host interface. By default, the current
drive will be low.
This signal will be high impedance when VID_STD[5:0] = 00h.
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
12 of 102
Table 1-1: Pin Descriptions (Continued)
Pin
Number
36
Name
Timing
Type
Description
TIMING_OUT_2
Synchronous
with PCLK1
~ PCLK3
Output
TIMING SIGNAL OUTPUT
Signal levels are LVCMOS/LVTTL compatible.
Selectable timing output.
Selectable from: H sync; H blanking; V sync; V blanking; F sync; F
digital; Display Enable; 10 field ID (film cadence); AFS video/audio
timing (GS4901B only); USER_1~4.
See Section 1.5 on page 23 for signal descriptions.
NOTE: Default output is H blanking.
The current drive capability of this pin may be set high or low via
designated registers in the host interface. By default, the current
drive will be low.
This signal will be high impedance when VID_STD[5:0] = 00h.
37
TIMING_OUT_3
Synchronous
with PCLK1
~ PCLK3
Output
TIMING SIGNAL OUTPUT
Signal levels are LVCMOS/LVTTL compatible.
Selectable timing output.
Selectable from: H sync; H blanking; V sync; V blanking; F sync; F
digital; Display Enable; 10 field ID (film cadence); AFS video/audio
timing (GS4901B only); USER_1~4.
See Section 1.5 on page 23 for signal descriptions.
NOTE: Default output is V Sync.
The current drive capability of this pin may be set high or low via
designated registers in the host interface. By default, the current
drive will be low.
This signal will be high impedance when VID_STD[5:0] = 00h.
39
TIMING_OUT_4
Synchronous
with PCLK1
~ PCLK3
Output
TIMING SIGNAL OUTPUT
Signal levels are LVCMOS/LVTTL compatible.
Selectable timing output.
Selectable from: H sync; H blanking; V sync; V blanking; F sync; F
digital; Display Enable; 10 field ID (film cadence); AFS video/audio
timing (GS4901B only); USER_1~4.
See Section 1.5 on page 23 for signal descriptions.
NOTE: Default output is V blanking.
The current drive capability of this pin may be set high or low via
designated registers in the host interface. By default, the current
drive will be low.
This signal will be high impedance when VID_STD[5:0] = 00h.
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
13 of 102
Table 1-1: Pin Descriptions (Continued)
Pin
Number
40
Name
Timing
Type
Description
TIMING_OUT_5
Synchronous
with PCLK1
~ PCLK3
Output
TIMING SIGNAL OUTPUT
Signal levels are LVCMOS/LVTTL compatible.
Selectable timing output.
Selectable from: H sync; H blanking; V sync; V blanking; F sync; F
digital; Display Enable; 10 field ID (film cadence); AFS video/audio
timing (GS4901B only); USER_1~4.
See Section 1.5 on page 23 for signal descriptions.
NOTE: Default output is F Sync.
The current drive capability of this pin may be set high or low via
designated registers in the host interface. By default, the current
drive will be low.
This signal will be high impedance when VID_STD[5:0] = 00h.
41
TIMING_OUT_6
Synchronous
with PCLK1
~ PCLK3
Output
TIMING SIGNAL OUTPUT
Signal levels are LVCMOS/LVTTL compatible.
Selectable timing output.
Selectable from: H sync; H blanking; V sync; V blanking; F sync; F
digital; Display Enable; 10 field ID (film cadence); AFS video/audio
timing (GS4901B only); USER_1~4.
See Section 1.5 on page 23 for signal descriptions.
NOTE: Default output is F digital.
The current drive capability of this pin may be set high or low via
designated registers in the host interface. By default, the current
drive will be low.
This signal will be high impedance when VID_STD[5:0] = 00h.
42
TIMING_OUT_7
Synchronous
with PCLK1
~ PCLK3
Output
TIMING SIGNAL OUTPUT
Signal levels are LVCMOS/LVTTL compatible.
Selectable timing output.
Selectable from: H sync; H blanking; V sync; V blanking; F sync; F
digital; Display Enable; 10 field ID (film cadence); AFS video/audio
timing (GS4901B only); USER_1~4.
See Section 1.5 on page 23 for signal descriptions.
NOTE: Default output is 10 Field ID (10FID).
The current drive capability of this pin may be set high or low via
designated registers in the host interface. By default, the current
drive will be low.
This signal will be high impedance when VID_STD[5:0] = 00h.
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
14 of 102
Table 1-1: Pin Descriptions (Continued)
Pin
Number
43
Name
Timing
Type
Description
TIMING_OUT_8
Synchronous
with PCLK1
~ PCLK3
Output
TIMING SIGNAL OUTPUT
Signal levels are LVCMOS/LVTTL compatible.
Selectable timing output.
Selectable from: H sync; H blanking; V sync; V blanking; F sync; F
digital; Display Enable; 10 field ID (film cadence); AFS video/audio
timing (GS4901B only); USER_1~4.
See Section 1.5 on page 23 for signal descriptions.
NOTE: Default output is Display Enable (DE).
The current drive capability of this pin may be set high or low via
designated registers in the host interface. By default, the current
drive will be low.
This signal will be high impedance when VID_STD[5:0] = 00h.
45
46, 47
LVDS/PCLK3_VDD
–
Power
Supply
Most positive power supply connection for PCLK3 output circuitry
and LVDS driver. Connect to +1.8V DC.
PCLK3, PCLK3
–
Output
CLOCK SIGNAL OUTPUTS
Signal levels are LVDS compatible.
Differential video clock output signal.
PCLK3/PCLK3 present a differential video sample rate clock output
to the application layer.
By default, after system reset, this output will operate at the
fundamental frequency determined by the setting of the
VID_STD[5:0] pins. It is possible to define other non-standard
fundamental clock rates using the host interface.
It is also possible to select different division ratios for the
PCLK3/PCLK3 outputs by programming designated registers in the
host interface. A clock output of the fundamental rate,
fundamental rate ÷2, or fundamental rate ÷4 may be selected.
The PCLK3/PCLK3 outputs will be high impedance when
VID_STD[5:0] = 00h.
48
LVDS/PCLK3_GND
–
Power
Supply
Ground connection for PCLK3 output circuitry and LVDS driver.
Connect to GND.
49
PCLK2
–
Output
CLOCK SIGNAL OUTPUT
Signal levels are LVCMOS/LVTTL compatible.
Video clock output signal.
PCLK2 presents a video sample rate clock output to the application
layer.
By default, after system reset, the PCLK2 output pin will operate at
the fundamental frequency determined by the setting of the
VID_STD[5:0] pins. It is possible to define other non-standard
fundamental clock rates using the host interface.
It is also possible to select different division ratios for the PCLK2
output by programming designated registers in the host interface.
A clock output of the fundamental rate, fundamental rate ÷2, or
fundamental rate ÷4 may be selected.
By setting designated registers in the host interface, the current
drive capability of this pin may be set high or low. By default, the
current drive will be low.
The PCLK2 output will be held LOW when VID_STD[5:0] = 00h.
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
15 of 102
Table 1-1: Pin Descriptions (Continued)
Pin
Number
51
Name
Timing
Type
Description
PCLK1
–
Output
CLOCK SIGNAL OUTPUT
Signal levels are LVCMOS/LVTTL compatible.
Video clock output signal.
PCLK1 presents a video sample rate clock output to the application
layer.
By default, after system reset, the PCLK1 output pin will operate at
the fundamental frequency determined by the setting of the
VID_STD[5:0] pins. It is possible to define other non-standard
fundamental clock rates using the host interface.
It is also possible to select different division ratios for the PCLK1
output by programming designated registers in the host interface.
A clock output of the fundamental rate, fundamental rate ÷2, or
fundamental rate ÷4 may be selected.
By setting designated registers in the host interface, the current
drive capability of this pin may be set high or low. By default, the
current drive will be low.
The PCLK1 output will be held LOW when VID_STD[5:0] = 00h.
52
PCLK1&2_GND
–
Power
Supply
Ground connection for PCLK1&2 circuitry. Connect to GND.
53
PCLK1&2_VDD
–
Power
Supply
Most positive power supply connection for PCLK1&2 circuitry.
Connect to +1.8V DC.
54
PhS_VDD
–
Power
Supply
Most positive power supply connection for the video clock phase
shift internal block. Connect to +1.8V DC.
55
PhS_GND
–
Power
Supply
Ground connection for the video clock phase shift internal block.
Connect to GND.
56
JTAG/HOST
Non
Synchronous
Input
CONTROL SIGNAL INPUT
Signal levels are LVCMOS/LVTTL compatible.
Used to select JTAG Test Mode or Host Interface Mode.
When set HIGH, CS_TMS, SCLK_TCLK, SDOUT_TDO, and SDIN_TDI
are configured for JTAG boundary scan testing.
When set LOW, CS_TMS, SCLK_TCLK, SDOUT_TDO, and SDIN_TDI are
configured as GSPI pins for normal host interface operation.
57
SCLK_TCLK
Non
Synchronous
Input
SIGNAL INPUT
Signal levels are LVCMOS/LVTTL compatible.
Serial Data Clock / Test Clock.
All JTAG / Host Interface address and data are shifted into/out of
the device synchronously with this clock.
Host Mode (JTAG/HOST = LOW):
SCLK_TCLK operates as the host interface serial data clock, SCLK.
JTAG Test Mode (JTAG/HOST = HIGH):
SCLK_TCLK operates as the JTAG test clock, TCLK.
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
16 of 102
Table 1-1: Pin Descriptions (Continued)
Pin
Number
58
Name
Timing
Type
Description
SDIN_TDI
Synchronous
with
SCLK_TCLK
Input
SIGNAL INPUT
Signal levels are LVCMOS/LVTTL compatible.
Serial Data Input / Test Data Input.
Host Mode (JTAG/HOST = LOW):
SDIN_TDI operates as the host interface serial input, SDIN, used to
write address and configuration information to the internal
registers of the device.
JTAG Test Mode (JTAG/HOST = HIGH):
SDIN_TDI operates as the JTAG test data input, TDI.
59
SDOUT_TDO
Synchronous
with
SCLK_TCLK
Output
SIGNAL INPUT
Signal levels are LVCMOS/LVTTL compatible.
Serial Data Output / Test Data Output.
Host Mode (JTAG/HOST = LOW):
SDOUT_TDO operates as the host interface serial output, SDOUT,
used to read status and configuration information from the internal
registers of the device.
JTAG Test Mode (JTAG/HOST = HIGH):
SDOUT_TDO operates as the JTAG test data output, TDO.
60
CS_TMS
Synchronous
with
SCLK_TCLK
Input
SIGNAL INPUT
Signal levels are LVCMOS/LVTTL compatible.
Chip Select / Test Mode Select.
Host Mode (JTAG/HOST = LOW):
CS_TMS operates as the host interface chip select, CS, and is active
LOW.
JTAG Test Mode (JTAG/HOST = HIGH):
CS_TMS operates as the JTAG test mode select, TMS, and is active
HIGH.
61
RESET
Non
Synchronous
Input
CONTROL SIGNAL INPUT
Signal levels are LVCMOS/LVTTL compatible.
Used to reset the internal operating conditions to their default
settings or to reset the JTAG test sequence.
Host Mode (JTAG/HOST = LOW):
When asserted LOW, all host registers and functional blocks will be
set to their default conditions. All input and output signals will
become high impedance, except PCLK1 and PCLK2, which will be set
LOW.
When set HIGH, normal operation of the device will resume.
The user must hold this pin LOW during power-up and for a
minimum of 500 uS after the last supply has reached its operating
voltage.
JTAG Test Mode (JTAG/HOST = HIGH):
When asserted LOW, all host registers and functional blocks will be
set to their default conditions and the JTAG test sequence will be
held in reset.
When set HIGH, normal operation of the JTAG test sequence will
resume.
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
17 of 102
Table 1-1: Pin Descriptions (Continued)
Pin
Number
64
Name
Timing
Type
Description
GENLOCK
Non
Synchronous
Input
CONTROL SIGNAL INPUT
Signal levels are LVCMOS/LVTTL compatible.
Selects Genlock mode or Free Run mode.
When this pin is set LOW and the device has successfully genlocked
the output to the input reference, the device will enter Genlock
mode. The video clock and timing outputs will be frequency and
phase locked to the detected reference signal.
When this pin is set HIGH, the video clock and the reference-timing
generator will free-run.
By default, the GS4901B’s audio clocks will be genlocked to the
output video clock regardless of the setting of this pin.
NOTE: The user must apply a reference to the input of the device
prior to setting GENLOCK = LOW. If the GENLOCK pin is set LOW
and no reference signal is present, the generated clock and timing
outputs of the device may correspond to the internal default
settings of the chip until a reference is applied.
–
Ground Pad
External Crystal Connection
38pF
6 X1
–
–
Ground pad on bottom of package must be soldered to main
ground plane of PCB.
External Clock Source Connection
6 X1
external
clock
1M
7 X2
7 X2
24pF
NC
Notes:
1. Capacitor values listed represent the total capacitance,
including discrete capacitance and parasitic board capacitance.
2. X1 serves as an input, which may alternatively accept a 27MHz clock
source. To accomodate this, mismatched capacitor values are recommended.
Figure 1-1: XTAL1 and XTAL2 Reference Circuits
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
18 of 102
1.4 Pre-Programmed Recognized Video Standards
Table 1-2 describes the video standards recognized by the GS4901B/GS4900B. The
device will automatically recognize VID_STD[5:0] = 1 to 10. In order to enable the device
to recognize and lock to any of the HD reference formats defined by VID_STD[5:0] = 11
to 38, the user must set the corresponding bit LOW in the Reference_Standard_Disable
register, located at address 11h-13h of the host interface. In addition, the user must set
the HD_Reference_Enable bit of register 82h[7] HIGH.
Please see the descriptions of the Reference_Standard_Disable and
HD_Reference_Enable registers in Section 3.10.3 on page 67.
If an HD reference format is left disabled in the Reference_Standard_Disable register, or
if the HD_Reference_Enable bit is not set HIGH in register 82h, the device will NOT
recognize this format should it be applied to the input of the device.
The user may select VID_STD[5:0] = 1 or 3-10 ONLY as output formats.
If desired, the external VID_STD[5:0] pins may be ignored by setting bit 1 of the
Video_Control register, and the video standard may instead be selected via the
VID_STD[5:0] register of the host interface (see Section 3.10.3 on page 67). Although the
external VID_STD[5:0] pins will be ignored in this case, they should not be left floating.
NOTE: VID_STD[5:4] should always be set LOW by the application layer since these pins
are not required to select output video standards 1 to 10.
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
19 of 102
4fsc 525 / 2:1
interlace
Composite PAL 625
/ 2:1 interlace / 25
601 525 / 2:1
interlace
601 625 / 2:1
interlace
601 – 18MHz 525
/ 2:1 interlace
601 – 18 MHz 625
/ 2:1 interlace
720x486/59.94/2:1
interlace
720x576/50/2:1
interlace
720x483/59.94/1:1
progressive
720x576/50/1:1
progressive
1280x720/60/1:1
progressive
1280x720/59.94/1:1
progressive
1
2*
3
4‡
5
6‡
7
8‡
9
10
11*
12*
74.175
74.25
54
54
54
54
36
36
27
27
–
1650
1650
1728
1716
3456
3432
2304
2288
1728
1716
–
910
–
–
14.32
PCLKS /
Total
Line
Video PCLK
Frequency
(MHz)
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
PCLK1&2 =LOW.
PCLK3/PCLK3 = High
Impedance
System
Nomenclature
0
VID_STD
[5:0]
Table 1-2: Recognized Video Standards
750
750
625
525
625
525
625
525
625
525
625
525
–
Total Lines
/ Frame
1280
1280
1440
1440
2880
2880
1920
1920
1440
1440
–
768
–
PCLKS /
Active
Line
80
80
127
127
252
252
169
169
127
127
–
67
–
H Sync
Width
(Clocks)
tri
tri
negative
negative
negative
negative
negative
negative
negative
negative
negative
negative
–
H Sync
Polarity
5
5
5
6
2.5
3
2.5
3
2.5
3
2.5
3
–
V Sync
Width
(Lines)
negative
negative
negative
negative
negative
negative
negative
negative
negative
negative
negative
negative
–
V Sync
Polarity
720
720
576
483
576
486
576
486
576
486
576
486
–
Active
Lines /
Frame
20 of 102
SMPTE 296M
SMPTE 296M
ITU-R BT.1358 /
SMPTE 347M
SMPTE 293M
/ SMPTE 347M
ITU-R BT.799
/ SMPTE 347M
SMPTE RP174 /
SMPTE 347M
ITU-R BT.601-5
SMPTE 267M
ITU-R BT.601-5
SMPTE
125M/267M
–
SMPTE 244M
–
Scan Format
Standard
1280/720/50/1:1
progressive
1280x720/30/1:1
progressive
1280x720/29.97/1:1
progressive
1280x720/25/1:1
progressive
1280x720/24/1:1
progressive
1280x720/23.98/1:1
progressive
1920x1035/60/2:1
interlace
1920x1035/59.94/2:1
interlace
1920x1080/60/1:1
progressive
1920x1080/59.94/1:1
progressive
1920x1080/50/1:1
progressive
Reserved
1920x1080/60/2:1
interlace
1920x1080/59.94/2:1
interlace
13*
14*
15*
16*
17*
18*
19*
20*
21*
22*
23*
24*
25*
26*
74.175
74.25
–
148.5
148.35
148.5
74.175
74.25
74.175
74.25
74.25
2200
2200
–
2640
2200
2200
2200
2200
4125
4125
3960
3300
3300
74.25
74.175
1980
PCLKS /
Total
Line
74.25
Video PCLK
Frequency
(MHz)
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
System
Nomenclature
VID_STD
[5:0]
Table 1-2: Recognized Video Standards (Continued)
1125
1125
–
1125
1125
1125
1125
1125
750
750
750
750
750
750
Total Lines
/ Frame
1920
1920
–
1920
1920
1920
1920
1920
1280
1280
1280
1280
1280
1280
PCLKS /
Active
Line
80
80
–
80
80
80
80
80
80
80
80
80
80
80
H Sync
Width
(Clocks)
tri
tri
–
tri
tri
tri
tri
tri
tri
tri
tri
tri
tri
tri
H Sync
Polarity
5
5
–
5
5
5
5
5
5
5
5
5
5
5
V Sync
Width
(Lines)
negative
negative
–
negative
negative
negative
negative
negative
negative
negative
negative
negative
negative
negative
V Sync
Polarity
1080
1080
–
1080
21 of 102
SMPTE 274M
SMPTE 274M
–
SMPTE 274M
SMPTE 274M
SMPTE 274M
1080
1080
SMPTE 260M
SMPTE 260M
SMPTE 296M
SMPTE 296M
SMPTE 296M
SMPTE 296M
SMPTE 296M
SMPTE 296M
Scan Format
Standard
1035
1035
720
720
720
720
720
720
Active
Lines /
Frame
1920x1080/50/2:1
interlace
Reserved
1920x1080/30/1:1
progressive
1920x1080/30/PsF
1920x1080/29.97/1:1
progressive
1920x1080/29.97/PsF
1920x1080/25/1:1
progressive
1920x1080/25/PsF
1920x1080/24/1:1
progressive
1920x1080/24/PsF
1920x1080/23.98/1:1
progressive
1920x1080/23.98/PsF
27*
28*
29*
30*
31*
32*
33*
34*
35*
36*
37*
38*
74.175
74.175
74.25
74.25
74.25
74.25
74.175
74.175
74.25
74.25
–
74.25
Video PCLK
Frequency
(MHz)
2750
2750
2750
2750
2640
2640
2200
2200
2200
2200
–
2640
PCLKS /
Total
Line
1125
1125
1125
1125
1125
1125
1125
1125
1125
1125
–
1125
Total Lines
/ Frame
1920
1920
1920
1920
1920
1920
1920
1920
1920
1920
–
1920
PCLKS /
Active
Line
80
80
80
80
80
80
80
80
80
80
–
80
H Sync
Width
(Clocks)
tri
tri
tri
tri
tri
tri
tri
tri
tri
tri
–
tri
H Sync
Polarity
5
5
5
5
5
5
5
5
5
5
–
5
V Sync
Width
(Lines)
negative
negative
negative
negative
negative
negative
negative
negative
negative
negative
–
negative
V Sync
Polarity
1080
1080
1080
1080
1080
1080
1080
1080
1080
1080
–
1080
Active
Lines /
Frame
SMPTE RP 211
SMPTE 274M
SMPTE RP 211
SMPTE 274M
SMPTE RP 211
SMPTE 274M
SMPTE RP 211
SMPTE 274M
SMPTE RP 211
SMPTE 274M
–
SMPTE 274M
Scan Format
Standard
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
22 of 102
‡ When VID_STD = 4, 6, or 8, the Vblanking output pulse width is 2 lines too long for field 1 and 1 line too short for field 2 when compared to the digital timing defined in ITU-R
BT.656 and ITU-R BT.799.
* VID_STD[5:0] = 2 and 11-38 are recognized as input references only. In addition, VID_STD[5:0] = 11-38 must be enabled in the Reference_Standard_Disable register and the
HD_Reference_Enable bit of register 82h[7] must be set HIGH before they will be recognized by the device.
System
Nomenclature
VID_STD
[5:0]
Table 1-2: Recognized Video Standards (Continued)
1.5 Output Timing Signals
Table 1-3 describes the output timing signals available to the user via pins
TIMING_OUT_1 to TIMING_OUT_8. The user may output any of the signals listed below
on each pin by programming the Output_Select registers beginning at address 43h of the
host interface.
Table 1-3: Output Timing Signals
Signal Name
Description
Default Output Pin
H Sync
The H Sync signal has a leading edge at the start of the horizontal sync
pulse. Its width is determined by the selected video standard (see
Table 1-2).
TIMING_OUT_1
In Genlock mode the leading edge of the output H Sync signal is
nominally simultaneous with the half amplitude point of the reference
HSYNC input. This timing may be offset using the Genlock Offset registers
beginning at address 1Bh of the host interface (see Section 3.2.1.1 on
page 36).
By default, after system reset, the polarity of the H Sync signal output will
be active LOW. The polarity may be selected as active HIGH by
programming the Polarity register at address 56h of the host interface
(see Section 3.10.3 on page 67).
H Blanking
The H Blanking signal is used to indicate the portion of the video line not
containing active video data.
TIMING_OUT_2
The H Blanking signal will be LOW (default polarity) for the portion of the
video line containing valid video samples. The signal will be LOW at the
first valid pixel of the line, and HIGH after the last valid pixel of the line.
The H Blanking signal remains HIGH throughout the horizontal blanking
period.
The width of this signal will be determined by the selected video standard
(see Table 1-2).
When in Genlock mode, the output H Blanking signal will be phase locked
to the reference HSYNC input. This timing may be offset using the
Genlock Offset registers beginning at address 1Bh of the host interface
(see Section 3.2.1.1 on page 36).
The default polarity of this signal may be inverted by programming the
Polarity register at address 56h of the host interface (see Section 3.10.3 on
page 67).
V Sync
The V Sync timing signal has a leading edge at the start of the vertical sync
pulse. Its width is determined by the selected video standard (see
Table 1-2).
TIMING_OUT_3
The leading edge of V Sync is nominally simultaneous with the leading
edge of the first broad pulse.
When in Genlock mode, the output V Sync signal will be phase locked to
the reference VSYNC input. This timing may be offset using the Genlock
Offset registers beginning at address 1Bh of the host interface (see
Section 3.2.1.1 on page 36).
By default, after system reset, the polarity of the V Sync signal output will
be active LOW. The polarity may be selected as active HIGH by
programming the Polarity register at address 56h of the host interface
(see Section 3.10.3 on page 67).
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
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December 2009
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Table 1-3: Output Timing Signals (Continued)
Signal Name
Description
Default Output Pin
V Blanking
The V Blanking signal is used to indicate the portion of the video
field/frame not containing active video lines.
TIMING_OUT_4
The V Blanking signal will be LOW (default polarity) for the portion of the
field/frame containing valid video data, and will be HIGH throughout the
vertical blanking period.
The width of this signal will be determined by the selected video standard
(see Table 1-2).
When in Genlock mode, the output V Blanking signal will be phase locked
to the reference VSYNC input. This timing may be offset using the Genlock
Offset registers beginning at address 1Bh of the host interface (see
Section 3.2.1.1 on page 36).
The default polarity of this signal may be inverted by programming the
Polarity register at address 56h of the host interface (see Section 3.10.3 on
page 67).
NOTE: When VID_STD = 4, 6, or 8, the Vblanking output pulse width is 2
lines too long for field 1 and 1 line too short for field 2 when compared to
the digital timing defined in ITU-R BT.656 and ITU-R BT.799.
F Sync
The F Sync signal is used to indicate field 1 and field 2 for interlaced video
formats.
TIMING_OUT_5
The F Sync signal will be HIGH (default polarity) for the entire period of
field 1. It will be LOW for all lines in field 2 and for all lines in progressive
scan systems.
The width and timing of this signal will be determined by the V Sync
parameters of the selected video standard (see Table 1-2). The F Sync
signal always changes state on the leading edge of V Sync.
When in Genlock mode, the output F Sync signal will be phase locked to
the reference FSYNC input. This timing may be offset using the Genlock
Offset registers beginning at address 1Bh of the host interface (see
Section 3.2.1.1 on page 36).
The default polarity of this signal may be inverted by programming the
Polarity register at address 56h of the host interface (see Section 3.10.3 on
page 67).
F Digital
F Digital is used in digital interlaced standards to indicate field 1 and field
2.
TIMING_OUT_6
The F Digital changes state at the leading edge of every V Blanking pulse.
It will be LOW (default polarity) for the entire period of field 1 and for all
lines in progressive scan systems. It will be HIGH for all lines in field 2 .
The width and timing of this signal will be determined by the timing
parameters of the selected video standard (see Table 1-2).
When in Genlock mode, the output F Digital signal will be phase locked to
the reference FSYNC input. This timing may be offset using the Genlock
Offset registers beginning at address 1Bh of the host interface (see
Section 3.2.1.1 on page 36).
The default polarity of this signal may be inverted by programming the
Polarity register at address 56h of the host interface (see Section 3.10.3 on
page 67).
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
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December 2009
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Table 1-3: Output Timing Signals (Continued)
Signal Name
Description
Default Output Pin
10 Field Identification
The 10 Field Identification (10FID) signal is used to indicate the 10-field
sequence for 29.97Hz, 30Hz, 59.94Hz and 60Hz video standards. It will be
LOW for output standards with other frame rates.
TIMING_OUT_7
The sequence defines the phase relationship between film frames and
video frames, so that cadence may be maintained in mixed format
environments.
The 10FID signal will be HIGH (default polarity) for one line at the start of
the 10-field sequence. It will be LOW for all other lines. The signal’s rising
and falling edges will be simultaneous with the leading edge of the H
Sync output signal.
Alternatively, by setting bit 4 of the Video_Control register (see
Section 3.10.3 on page 67), the 10FID output signal may be configured to
go HIGH (default polarity) on the leading edge of the H Sync output on
line 1 of the first field in the 10 field sequence, and be reset LOW on the
leading edge of the H Sync pulse of the first line of the second field in the
10 field sequence.
When in Genlock mode, the output 10FID signal will be phase locked to
the 10FID reference input. If a 10FID input is not provided to the device,
the user must configure the 10FID output using register 1Ah of the host
interface (see Section 3.8.1 on page 58).
For applications involving audio, this signal may be used in place of the
AFS signal if the format selected is appropriate for a 10 field AFS
repetition rate, and the desired phase relationship of audio to video clock
phasing coincides with the desired film frame cadence.
The default polarity of this signal may be inverted by programming the
Polarity register at address 56h of the host interface (see Section 3.10.3 on
page 67).
Please see Section 3.8.1 on page 58 for more detail on the 10FID output
signal.
Display Enable
The Display Enable (DE) signal is used to indicate the display enable for
graphic display interfaces.
TIMING_OUT_8
This signal will be HIGH (default polarity) whenever pixel information is to
be displayed on the display device (i.e. whenever both H Blanking and V
Blanking are in the active video state)
The width and timing of this signal will be determined by the timing
parameters of the selected video standard (see Table 1-2).
The default polarity of this signal may be inverted by programming the
Polarity register at address 56h of the host interface (see Section 3.10.3 on
page 67).
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
25 of 102
Table 1-3: Output Timing Signals (Continued)
Signal Name
Description
Default Output Pin
Audio Frame Sync
The Audio Frame Sync (AFS) signal is HIGH (default polarity) for the
duration of the first line of the n’th video frame to indicate that the ACLK
dividers are reset at the start of line 1 of that frame. It is defined
according to the frame rate of the video format and the selected audio
sample rate programmed via the VID_STD[5:0] and ASR_SEL[2:0] pins or
the host interface.
–
(GS4901B only)
For example, if the video format is based on a 59.94Hz frame rate and the
audio sample rate clock is 48kHz, then n=5, and the AFS signal will be
identical to the 10FID signal.
By default, the AFS signal is reset by the 10 Field Identification (10FID)
reference input. This feature may be disabled using the Audio_Control
register at address 31h of the host interface (see Section 3.10.3 on page
67). The AFS signal may also be reset using register 1Ah of the host
interface. With no reference, the frame divide by “n” controlling the AFS
signal will free-run at an arbitrary phase.
The default polarity of this signal may be inverted by programming the
Polarity register at address 56h of the host interface (see Section 3.10.3).
Please see Section 3.8.2 on page 59 for more detail on the AFS output
signal.
USER_1~4
The GS4901B/GS4900B offers four user programmable output signals. Each
USER signal is controlled by four timing registers and a polarity select bit.
The timing registers define the start and stop times in H pixels and V lines
and begin at address 57h of the host interface (see Section 3.10.3 on page
67).
–
Each user signal is individually programmable and the polarity, position,
and width of each output may be defined with respect to the H, V, and F
output timings of the device. Each output signal may be programmed in
both the horizontal and vertical dimensions relative to the leading edges
of H and V Sync. If desired, the pulses produced may then be combined
with a logical AND, OR, or XOR function to produce a composite signal
(for example, a horizontal back porch pulse during active lines only, or the
active part of lines 15 through 20 for vertical information retrieval). Each
output has selectable polarity.
Please see Section 3.8.3 on page 60 for more detail on the USER_1~4
output signals.
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
26 of 102
2. Electrical Characteristics
2.1 Absolute Maximum Ratings
Parameter
Conditions
Value/Units
Supply Voltage Core and Analog
–
-0.3V to +2.1V
–
-0.3V to +3.6V
IO_VDD = +3.3V
-0.3V to +5.5V
IO_VDD = +1.8V
-0.3V to +3.6V
Operating Temperature
–
-20°C < TA < 85°C
Storage Temperature
–
-50°C < TSTG < 125°C
Soldering Temperature
–
260°C
ESD protection on all pins
–
1 kV
(CORE_VDD, VID_PLL_VDD, AUD_PLL_VDD,
PhS_VDD, ANALOG_VDD)
Supply Voltage I/O
(IO_VDD, XTAL_VDD)
Input Voltage Range (any input)
2.2 DC Electrical Characteristics
Table 2-1: DC Electrical Characteristics
VDD = 1.8V, TA = 0°C to 70°C, unless otherwise specified.
Parameter
Symbol
Condition
Min
Typ
Max
Units
Notes
Operating Temperature Range
TA
–
0
25
70
°C
1
Core power supply voltage
CORE_VDD
–
1.71
1.8
1.89
V
–
Digital I/O Buffer Power Supply
Voltage
IO_VDD
1.8V Operation
1.71
1.8
1.89
V
–
IO_VDD
3.3V Operation
3.135
3.3
3.465
V
–
Video PLL Power Supply Voltage
VID_PLL_VDD
–
1.71
1.8
1.89
V
–
Audio PLL Power Supply Voltage
(GS4901B only)
AUD_PLL_VDD
–
1.71
1.8
1.89
V
–
Analog Power Supply Voltage
ANALOG_VDD
–
1.71
1.8
1.89
V
–
Crystal Buffer Power Supply
Voltage
XTAL_VDD
1.8V Operation
1.71
1.8
1.89
V
–
XTAL_VDD
3.3V Operation
3.135
3.3
3.465
V
–
PhS_VDD
–
1.71
1.8
1.89
V
–
System
Video Clock Phase Shift Supply
Voltage
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
27 of 102
Table 2-1: DC Electrical Characteristics (Continued)
VDD = 1.8V, TA = 0°C to 70°C, unless otherwise specified.
Parameter
Symbol
GS4901B Power Consumption
(IO_VDD = 1.8V Nominal)
P1.8V Rail
P3.3V Rail
Condition
Max PCLK
Frequency
P1.8V Rail
Min
Typ
Max
Units
Notes
–
300
425
mW
–
N/A
N/A
N/A
mW
–
–
270
395
mW
–
N/A
N/A
N/A
mW
–
–
240
320
mW
–
–
90
170
mW
–
–
210
290
mW
–
–
90
170
mW
–
–
250
375
mW
–
N/A
N/A
N/A
mW
–
–
220
345
mW
–
N/A
N/A
N/A
mW
–
–
190
270
mW
–
–
90
170
mW
–
–
160
240
mW
–
–
90
170
mW
–
PCLK = 27MHz
P3.3V Rail
GS4901B Power Consumption
(IO_VDD = 3.3V Nominal)
P1.8V Rail
P3.3V Rail
Max PCLK
Frequency
P1.8V Rail
PCLK = 27MHz
P3.3V Rail
GS4900B Power Consumption
(IO_VDD = 1.8V Nominal)
P1.8V Rail
P3.3V Rail
Max PCLK
Frequency
P1.8V Rail
PCLK = 27MHz
P3.3V Rail
GS400B Power Consumption
(IO_VDD = 3.3V Nominal)
P1.8V Rail
P3.3V Rail
Max PCLK
Frequency
P1.8V Rail
PCLK = 27MHz
P3.3V Rail
Digital I/O
Input Voltage, Logic LOW
VIL
1.8V Operation
–
–
0.35 x
VDD
V
–
VIL
3.3V Operation
–
–
0.8
V
–
VIH
1.8V Operation
0.65 x
IO_VDD
–
3.6
V
–
VIH
3.3V Operation
2.145
–
5.25
V
–
Output Voltage, Logic LOW
VOL
current drive =
HIGH or LOW as
selected
–
–
0.4
V
2
Output Voltage, Logic HIGH
VOH
current drive =
HIGH or LOW as
selected
0.65 x
IO_VDD
–
–
V
2
Input Voltage, Logic HIGH
Digital Output Currents
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
28 of 102
Table 2-1: DC Electrical Characteristics (Continued)
VDD = 1.8V, TA = 0°C to 70°C, unless otherwise specified.
Parameter
Symbol
Condition
Min
Typ
Max
Units
Notes
Timing Output Drive Current
–
IO_VDD = 1.8V
current drive =
LOW
–
5
–
mA
–
–
IO_VDD = 3.3V
current drive =
LOW
–
10
–
mA
–
–
IO_VDD = 1.8V
current drive =
HIGH
–
7
–
mA
–
–
IO_VDD = 3.3V
current drive =
HIGH
–
14
–
mA
–
–
IO_VDD = 1.8V
current drive =
LOW
–
5
–
mA
–
–
IO_VDD = 3.3V
current drive =
LOW
–
7
–
mA
–
–
IO_VDD = 1.8V
current drive =
HIGH
–
7
–
mA
–
–
IO_VDD = 3.3V
current drive =
HIGH
–
14
–
mA
–
Output Voltage LVDS, Common
Mode
VOCM
–
1.125
1.25
1.375
V
3
Output Voltage LVDS,
Differential
VODIFF
–
–
350
–
mV
3
LVDS High-impedance Leakage
Current
–
To 1.8V or GND
–
–
1.4
uA
–
Clock Output Drive Current
NOTES
1. All DC and AC electrical parameters within specification.
2. Assuming that the current being sourced or sinked is less than the Timing Output Drive Current specified.
3. Into a 100Ω termination connected between PCLK3 and PCLK3.
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
29 of 102
2.3 AC Electrical Characteristics
Table 2-2: AC Electrical Characteristics
VDD = 1.8V, TA = 0°C to 70°C, unless otherwise specified.
Parameter
Symbol
Condition
Min
Typ
Max
Units
Notes
–
from when the
reference input is
first present
–
2
4
frames
–
PCLK Output Frequency
–
–
3.375
–
165
MHz
–
PCLK Jitter
–
XTAL_VDD = 3.3V
–
350
–
ps
1, 2
PCLK Duty Cycle
–
–
40
–
60
%
–
PCLK1 & PCLK2 Rise/Fall Times
15pF load
20% - 80%
–
IO_VDD = 1.8V
current drive = LOW
–
–
1.7
ns
–
–
IO_VDD = 3.3V
current drive = LOW
–
–
1.5
ns
–
–
IO_VDD = 1.8V
current drive = HIGH
–
–
1.1
ns
–
–
IO_VDD = 3.3V
current drive = HIGH
–
–
0.9
ns
–
–
100Ω differential
load
–
–
850
ps
–
-3
–
3
ns
3
System
Reference Detection Time
Digital I/O
PCLK3 Rise/Fall Time
20% - 80%
10pF to ground per
pin
PCLK Outputs Relative Timing
Skew
–
default PCLK phase
delay of zero
ACLK Frequency
(GS4901B only)
–
–
0.0097
–
49.152
MHz
–
ACLK Duty Cycle
(GS4901B only)
–
–
40
–
60
%
4
ACLK1-3 Rise/Fall Times
15pF load
20% - 80%
(GS4901B only)
–
IO_VDD = 1.8V
current drive = LOW
–
–
3.0
ns
–
–
IO_VDD = 3.3V
current drive = LOW
–
–
1.5
ns
–
–
IO_VDD = 1.8V
current drive = HIGH
–
–
2.5
ns
–
–
IO_VDD = 3.3V
current drive = HIGH
–
–
1.4
ns
–
–
–
-3
–
3
ns
3
ACLK Outputs Relative
Timing Skew
(GS4901B only)
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
30 of 102
Table 2-2: AC Electrical Characteristics (Continued)
VDD = 1.8V, TA = 0°C to 70°C, unless otherwise specified.
Parameter
Symbol
Condition
Min
Typ
Max
Units
Notes
Digital Timing Output Delay
Time
tOD
–
–
–
4.3
ns
5
Digital Timing Output Hold Time
tOH
–
1
–
–
ns
5
Digital Timing Output Rise/Fall
Times
15pF load
20% - 80%
–
IO_VDD = 1.8V
current drive = LOW
–
–
3.0
ns
–
–
IO_VDD = 3.3V
current drive = LOW
–
–
1.5
ns
–
–
IO_VDD = 1.8V
current drive = HIGH
–
–
2.5
ns
–
–
IO_VDD = 3.3V
current drive = HIGH
–
–
1.4
ns
–
GSPI Input Clock Frequency
fGSPI
–
–
–
10.0
MHz
6
GSPI Clock Duty Cycle
DCGSPI
–
40
–
60
%
6
GSPI Input Setup Time
t3 in
Figure 3-15
–
1.5
–
–
ns
6
GSPI Input Hold Time
t8 in
Figure 3-15
–
1.5
–
–
ns
6
GSPI
NOTES
1. The video output clock may be directly connected to Gennum’s GS9062 serializer for a SMPTE-compliant SDI output with output jitter below
0.2UI.
2. All output standards EXCEPT VID_STD[5:0] = 1 (450ps typ.) and VID_STD[5:0] = 5 or 6 (500ps typ.)
3. Timings from any CLK output to any other CLK output.
4. If fs=96kHz and ACLK is configured to output a clock signal at 192fs or 384fs, a 512fs clock will typically have a 33% duty cycle distortion.
See Section 3.7.2 on page 54.
5. With PCLK phasing delay set to nominal (zero offset), each increment of the clock phasing adjustment decreases output hold time and delay
time by a nominal 700ps. The times tOD and tOH are defined in Figure 2-1.
6. For detailed GSPI timing parameters, please refer to Table 3-12.
tOH
tOD
PCLK
50%
VOH
VOH
VOL
VOL
TIMING_OUT
Figure 2-1: PCLK to TIMING_OUT Signal Output Timing
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
31 of 102
Table 2-3: Suggested External Crystal Specification
27.000000 MHz
AT Cut
Nominal Dissipation = 50 uW
Frequency accuracy at 25°C = +/- 10ppm
Frequency variation 0-70°C = +/- 10ppm
ASR = 50 +/- 20Ω
NOTE: The user may select an appropriate crystal accuracy for their application. If the device is
operating in Free Run mode, the output clock and timing signals will have the same accuracy
as the crystal. However, if operating in Genlock mode, all output signals are based on the
input reference, and therefore a less accurate crystal may be sufficient. See Section 3.2 on
page 35.
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
32 of 102
2.4 Solder Reflow Profiles
The device is manufactured with Matte-Sn terminations and is compatible with both
standard eutectic and Pb-free solder reflow profiles. MSL qualification was performed
using the maximum Pb-free reflow profile shown in Figure 2-2. The recommended
standard Pb reflow profile is shown in Figure 2-3.
Temperature
60-150 sec.
20-40 sec.
260°C
250°C
3°C/sec max
217°C
6°C/sec max
200°C
150°C
25°C
Time
60-180 sec. max
8 min. max
Figure 2-2: Maximum Pb-free Solder Reflow Profile (preferred)
60-150 sec.
Temperature
10-20 sec.
230°C
220°C
3°C/sec max
183°C
6°C/sec max
150°C
100°C
25°C
Time
120 sec. max
6 min. max
Figure 2-3: Standard Pb Solder Reflow Profile
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
33 of 102
3. Detailed Description
3.1 Functional Overview
The GS4901B/GS4900B is a highly flexible, digitally controlled clock synthesis circuit
and timing generator with genlock capability.
The device has two main modes of operation: Genlock mode and Free Run mode. In
Genlock mode, the video clock and timing outputs, will be frequency and phase locked
to the detected reference input signal. In Free Run mode, the occurrence of all
frequencies is based on a 27MHz external crystal reference.
The GS4901B/GS4900B will recognize input reference signals conforming to 36
different video standards. It supports cross-locking, allowing the output to be genlocked
to an incoming reference that is different from the output video standard selected.
When the device is in Genlock mode and the input reference is removed, the
GS4901B/GS4900B will enter Freeze mode. In this mode, the output clock and timing
signals will maintain their previously genlocked phase and frequency to within +/2ppm.
The user may select to output one of 4 different video sample clock rates. The chosen
clock frequency may be further internally divided, and is available on two video clock
outputs and one LVDS video clock output pair. The video clocks may also be
individually phase delayed with respect to the timing outputs for clock skew control.
Eight user-selectable timing outputs are provided that can automatically produce the
following timing signals for 9 different video formats: HSync, Hblanking, VSync,
Vblanking, F sync, F digital, AFS (GS4901B only), DE, and 10FID.
In addition, the GS4901B provides three audio sample clock outputs that can produce
audio clocks up to 512fs with fs ranging from 9.7kHz to 96kHz. Audio to video phasing
is accomplished by either an external 10FID input reference, a 10FID signal specified via
internal registers, or a user-programmed audio frame sequence.
3.2 Modes of Operation
The GS4901B/GS4900B will operate in either Genlock mode or Free Run mode
depending on the setting of the GENLOCK pin. These two modes are described in
Section 3.2.1 on page 35 and Section 3.2.2 on page 39 respectively.
If desired, the external GENLOCK pin may be ignored by setting bit 5 of the
Genlock_Control register (address 16h) so that genlock can instead be controlled via the
host interface (see Section 3.10.3 on page 67). Although the external GENLOCK pin will
be ignored in this case, it should not be left floating.
3.2.1 Genlock Mode
When the application layer sets the GENLOCK pin LOW and the device has successfully
genlocked the outputs to the input reference, the GS4901B/GS4900B will enter Genlock
mode. In this mode, all clock and timing generator outputs will be frequency and phase
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
34 of 102
locked to the detected input reference signal. The PCLK outputs will be locked to the H
reference.
When in Genlock mode, the output clock and timing signals are generated using the
applied reference signal. The 27MHz crystal reference is necessary for operation;
however, neither crystal accuracy nor changes in crystal frequency (due to a shift in
operating temperature) will affect the output signals. For example, the output signals
will be generated with the same accuracy whether the 27MHz reference crystal has an
accuracy of 10ppm or 100ppm.
The GS4901B/GS4900B supports cross-locking, allowing the outputs to be genlocked to
an incoming reference that is different from the output video standard selected (see
Section 3.6 on page 47).
NOTE: The user must apply a reference to the input of the device prior to setting
GENLOCK = LOW. If the GENLOCK pin is set LOW and no reference signal is present, the
generated clock and timing outputs of the device may correspond to the internal default
settings of the chip until a reference is applied.
3.2.1.1 Genlock Timing Offset
By default, the phase of the clock and timing out signals is genlocked to the input
reference signal. These output signals may be phase adjusted with respect to the input
reference by programming the host interface (see Section 3.10.3 on page 67). Offsets are
separately programmable in terms of clock phase, horizontal phase, and vertical phase
(i.e. fractions of a pixel, pixels, and lines).
Genlock timing offsets can be used to co-time the output of a piece of equipment
containing the GS4901B/GS4900B with the outputs of other equipment at different
locations. The signal leaving the piece of equipment containing the GS4901B/GS4900B
may pass through processing equipment with significant fixed delays before arriving at
the switcher. These delays may include video line delays or even field delays. To
compensate for these delays, genlock timing offsets allow the user to back-time the
output of the equipment relative to the input reference.
Using the host interface, the following registers may be programmed once the device is
stably locked:
•
Clock_Phase_Offset (1Dh) - with a range of zero to one clock pulse in increments of
between 1/128 and 1/512 of a clock period (depending on the PCLK frequency). The
increments will be between 100ps and 150ps. All clock and timing output signals
will be delayed by the clock phase offset programmed in this register.
•
H_Offset (1Bh) - the difference between the reference HSYNC signal and the output
H Sync and/or H Blanking signal in clock pulses, with a control range of zero to +1
line. All timing output signals will be delayed by the horizontal offset programmed
in this register.
•
V_Offset (1Ch) - the difference between the reference VSYNC signal and the output
V Sync and/or V Blanking in lines, with a control range of zero to +1 frame. All
line-based timing output signals will be delayed by the vertical offset programmed
in this register.
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
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The encoding scheme for the Clock_Phase_Offset register (1Dh) is shown in Table 3-1.
The offset programmed will be in the positive direction. Note that the step size will
depend on the frequency of the output video clock.
Table 3-1: Clock_Phase_Offset [15:0] Encoding Scheme
VID_STD[5:0]
Setting
Output Video Clock
Frequency
1
fPCLK < 20MHz
Step Size
(Fraction
of a PCLK)
Maximum
Number of
Steps
1
-------512
511
Bits Required to
Set the Number
of Steps
b8b7b6b5b4b3b2b1b
Clock_Phase_Offset [15:0]
Settings
b8000001b8b7b6b5b4b3b2b1b0
0
3-6
20MHz < fPCLK < 40MHz
1
-------256
255
b7b6b5b4b3b2b1b0
b7000010b7b6b5b40b3b2b1b0
7-10
40MHz < fPCLK < 54MHz
1
-------128
127
b6b5b4b3b2b1b0
b6000100b6b5b400b3b2b1b0
Note: Program Clock_Phase_Offset = 0000 0000 0000 0000b to achieve a zero clock phase offset.
The value programmed in the H_Offset register (1Bh) must not exceed the maximum
number of clock periods per line of the outgoing video standard. Similarly, the value
programmed in the V_Offset register (1Ch) must not exceed the maximum number of
lines per frame of the outgoing standard. Both horizontal and vertical offsets will be in
the positive direction. Negative offsets (advances) are achieved by programming a value
in the appropriate register equal to the maximum allowable offset minus the desired
advance.
NOTES:
1. The device will delay all output timing signals by 2 PCLKs relative to the input
HSYNC reference. This will occur even when the H_Offset register is not
programmed. The user may compensate for this delay by subtracting 2 PCLK cycles
from the desired horizontal offset before loading the value into the host interface.
2. For both sync and blanking-based input references, the device will advance all
line-based output timing signals by 1 line relative to the input VSYNC reference for
all output standards except VID_STD[5:0] = 4, 6, and 8. This will occur even when
the V_Offset register is not programmed. The user may compensate for this
advance by adding 1 line to the desired vertical offset before loading this value into
the register.
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with GENLOCK
Data Sheet
37703 - 4
December 2009
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3. When locking the 525-line SD output standards to the “f/1.001” HD input reference
standards, the device will delay all line-based output timing signals by ΔVSync
lines relative to the input VSYNC reference. This will occur even when the V_Offset
register is not programmed. The user may compensate for this delay by subtracting
ΔVSync lines from the desired vertical offset before loading this value into the
register.
The value ΔVSync is given by the equation:
ΔVSync = H SYNC_IN_Period + ΔVSYNC _H SYNC – ( 2 × H SYNC_O U T_Period )
where:
HSYNC_IN_Period = the period of the H reference pulse
ΔVSYNC_HSYNC = the time difference between the leading edges of the applied V
and H reference pulses
Hsync_OUT_Period = the period of the generated H Sync output
See Figure 3-1. H_Feedback_Divide represents the numerator of the ratio of the
output clock frequency to the frequency of the H reference pulse.
HSYNC_IN_Period
HSYNC
VSYNC
D VSYNC_HSYNC
HSync_OUT_Period
H Sync
V Sync
D VSync
Figure 3-1: SD-HD Calculation
4. For sync-based input references, the device will advance all line-based output
timing signals by 1 line if the value programmed in the H_Offset register is greater
than 20. The user may compensate for this advance by adding 1 line to the desired
vertical offset before loading this value into the register. In addition, the internal
V_lock and F_lock signals reported in bits 3 and 4 of register 16h will be LOW when
H_Offset = 20 only, although the device will remained genlocked. The user may
choose to mask these lock signals such that the device will continue to report
genlock under this condition.
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with GENLOCK
Data Sheet
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December 2009
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5. For blanking-based input references, the device will advance all line-based output
timing signals by 1 line if the value programmed in the H_Offset register is greater
than the number of output video clock cycles from the start of H Sync to the end of
active video (Hsync_to_EAV) + 20. The value of Hsync_to_EAV is reported in
register 51h and changes according to the output VID_STD selected. The user may
compensate for this advance by adding 1 line to the desired vertical offset before
loading this value into the register. In addition, the internal V_lock and F_lock
signals reported in bits 3 and 4 of register 16h will be LOW when H_Offset =
Hsync_to_EAV + 20 only, although the device will remained genlocked. The user
may choose to mask these lock signals such that the device will continue to report
genlock under this condition.
6. The offsets that occur as described in notes 1-5 are independent of one another and
must be accounted for as such.
3.2.1.2 Freeze Mode
When the device is in Genlock mode and the input reference is removed, the
GS4901B/GS4900B will enter Freeze mode. The behaviour of the device during loss and
re-acquisition of an input reference signal is described in Section 3.5.3 on page 45.
In Freeze mode, the frequency of the output clock and timing signals will be maintained
to within +/- 2ppm. This assumes a loop bandwidth of 10Hz. Also, if the frequency of the
27MHz reference crystal shifts while in Freeze mode, the frequency of the output clock
and timing signals will shift as well.
3.2.2 Free Run Mode
The GS4901B/GS4900B will enter Free Run mode when the GENLOCK pin is set HIGH
by the application layer. In this mode, the occurrence of all frequencies is based on the
external 27MHz reference input. Therefore, the frequency of the output clock and
timing signals will have the same accuracy as the crystal reference.
If operating in Free Run mode, using a more accurate crystal (e.g. 10ppm) ensures more
accurate clock and timing signals are generated.
NOTE: In Free Run mode, the audio clocks of the GS4901B will remain genlocked to the
video clock.
Figure 3-2 summarizes the differences in output accuracy in each mode of operation.
Assuming a crystal reference of +/-100ppm, in Free Run mode the frequency of the
output clock and timing signals will be as accurate as the crystal. In Genlock mode the
frequency will be as accurate as the input reference regardless of the crystal accuracy.
In Freeze mode, the frequency of the output clock and timing signals will be maintained
to within +/- 2ppm.
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
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Assumption: Reference
XTAL is 27MHz+/-100ppm
+ t
t
+100ppm
+ t
+2ppm
-2ppm
27 MHz
- t
-100ppm
- t
Free Run
Genlock
Freeze
No Input
Reference
Reference
Applied
Reference
Lost
Time
NOTES:
1. t represents the temperature variability of the crystal
2. Diagram not to scale.
Figure 3-2: Output Accuracy and Modes of Operation
3.3 Output Timing Format Selection
At device power-up (described in Section 3.12 on page 94), the application layer should
immediately set the external VID_STD[5:0] and ASR_SEL[2:0] pins. The VID_STD[5:0]
pins are used to select a pre-programmed output video format. The ASR_SEL[2:0] pins
are only available on the GS4901B, and are used to select the fundamental audio
frequency or to turn off audio clock generation.
The output timing formats selectable by the user via the VID_STD[5:0] pins are listed in
Section 1.4 on page 19. Table 3-7 in Section 3.7.2 on page 54 lists the audio sample rates
available via the ASR_SEL[2:0] pins.
NOTE: The VID_STD[5:4] pins should be grounded by the application layer since these
pins are not required to select output video standards 1 to 10.
On power-up, the device will first check the status of the GENLOCK pin. If GENLOCK is
set LOW and a valid reference has been applied to the inputs, the device will output the
selected video standard while attempting to genlock. However, if a reference signal has
not been applied and GENLOCK=LOW, the initial clock and timing outputs may be
determined by the internal default settings of the chip. If GENLOCK is set HIGH, the
device will immediately enter Free Run mode and will correctly output the selected
video standard.
When operating in Free Run or Genlock mode, the GS4901B/GS4900B will continuously
monitor the settings of the VID_STD[5:0] and ASR_SEL[2:0] pins. If the user wishes to
change the format of the output clocks and timing signals, these pins may be
reconfigured at any time, although it is recommended that the device be reset when
changing output video standards.
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
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3.4 Input Reference Signals
The HSYNC, VSYNC, FSYNC, and 10FID reference signals are applied to the
GS4901B/GS4900B via the designated input pins.
To operate in Genlock mode, the input reference signals must be valid and must conform
to a recognized video standard (see Section 3.5 on page 43).
In Free Run mode, no input reference is required.
Section 3.4.1 on page 41 describes the HSYNC, VSYNC and FSYNC input timing. The
10FID input signal is discussed in Section 3.4.2 on page 42.
3.4.1 HSYNC, VSYNC, and FSYNC
The HSYNC, VSYNC, and FSYNC input reference signals may have analog timing, such
as from Gennum’s GS4981/82 sync separators (Figure 3-3), or may have digital timing,
such as from Gennum’s GS1559/60A/61 deserializers (Figure 3-4). Section 1.4 on page
19 lists the 36 pre-programmed video timing formats recognized by the
GS4901B/GS4900B.
If the input reference format does not include an F sync signal, the FSYNC pin should be
held LOW.
HSYNC
VSYNC
FSYNC
Figure 3-3: Example HSYNC, VSYNC, and FSYNC Analog Input Timing from a
Sync Separator
PCLK
LUMA DATA OUT
3FF
000
000
XYZ (eav)
3FF
000
000
XYZ (sav)
CHROMA DATA OUT
3FF
000
000
XYZ (eav)
3FF
000
000
XYZ (sav)
H
V
F
H:V:F TIMING - HD 20-BIT OUTPUT MODE
H Signal Timing
Typical H Timing
Alternative H Timing
Figure 3-4: Example H Blanking, V Blanking, and F Digital Input Timing from
an SDI Deserializer
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
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December 2009
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3.4.2 10FID
The 10FID input is a reset pin, which can be used to reset the divider for the 10FID output
signal. In the GS4901B, the 10FID input pin will also reset the divider for the AFS output
signal. This default setting may be modified using the Audio_Control register of the host
interface (see Section 3.10.3 on page 67).
The GS4901B will reset the phase of the audio clocks to the leading edge of the H Sync
output on line 1 of every output frame in which the 10FID input is HIGH.
If the input reference format does not include a 10 Field ID signal, the external 10FID
input pin should be held LOW.
The timing of the 10FID input signal is shown in Figure 3-5.
Total Line
10FID Input
Line 1, Frame 1 every 'n' frames
Horizontal Sync Input
Line 1 every n frames where:
n = 5 @ 29.97 fps, 30 fps
n = 10 @ 59.94 fps, 60 fps
Figure 3-5: 10FID Input Timing
3.4.3 Automatic Polarity Recognition
To accommodate any standards that employ the polarity of the H and V sync signals to
indicate the format of the display, the GS4901B/GS4900B will recognize H and V sync
polarity and automatically synchronize to the leading edge.
The polarities of the HSYNC and VSYNC signals are reported in bits 3 and 4 of the
Video_Status register. Additionally, bit 2 of this register reports the detection of either
analog or digital input timing. See Section 3.10.3 on page 67 for detailed register
descriptions.
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
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3.5 Reference Format Detector
The reference format detector checks the validity and analyzes the format of the input
reference signal. It is designed to accurately differentiate between 59.94 and 60Hz
frame rates.
As described in Section 1.4 on page 19, the GS4901B / GS4900B will automatically
recognize the SD video standards defined by VID_STD[5:0] = 1 to 10. However, in order
to enable the device to recognize and lock to any of the HD reference formats defined
by VID_STD[5:0] = 11 to 38, the user must set the corresponding bit LOW in the
Reference_Standard_Disable register, located at address 11h-13h of the host interface.
The user must also set the HD_Reference_Enable bit of register 82h[7] HIGH. See the
description of the Reference_Standard_Disable and HD_Reference_Enable registers in
Section 3.10.3 on page 67.
3.5.1 Horizontal and Vertical Timing Characteristic Measurements
When a reference signal is applied to the designated input pins, the GS4901B/GS4900B
will analyse the signal and report the following in registers 0Ah to 0Eh of the host
interface:
•
the number of 27MHz clock pulses between leading edges of the H input reference
signal (H_Period register)
•
the number of 27MHz clock pulses in 16 horizontal periods (H_16_Period register)
•
the number of H reference pulses between leading edges of the V input reference
signal (V_Lines register)
•
the number of H reference pulses in two vertical periods (V_2_Lines register)
•
the number of H reference pulses in one F period (F_Lines register)
These parameters may be read via the host interface and are used by the device to
determine reference signal validity.
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
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3.5.2 Input Reference Validity
Before the device attempts to operate in Genlock mode, the input signals applied to
HSYNC and VSYNC must be valid (SD references only) and must conform to one of the
recognized and enabled video standards, as described in Section 1.4 on page 19.
For an SD input reference signal to be considered valid, the periodicity of HSYNC must
be between 29.66us and 70us, and the periodicity of VSYNC must be between 16ms and
25ms. The FSYNC signal is not essential for validity. The REF_LOST pin will be set LOW
once the SD input reference signal is determined to be valid.
For HD input reference signals where the user has set the HD_Reference_Enable bit of
register 82h[7] HIGH, the device will not measure signal validity. In this case, the
REF_LOST pin will be LOW whenever any reference signal is present on the input.
The device then compares the timing parameters of the input reference signal to each of
the video standards that has been enabled in the the Reference_Standard_Disable
register (there may be up to 36 video standards if all HD standards are enabled). The
device will then determine if the input reference is one of the enabled and recognized
standards. If it is, the VID_STD[5:0] value for the format is written to the Input_Standard
register at address 0Fh of the host interface. If the reference format is unrecognized or
disabled, 00h is programmed in this register.
Once a reference signal is recognized by the device, VSYNC and FSYNC will no longer
be monitored. Loss of signal on these pins will not affect the operation of the device.
If the REF_LOST pin is HIGH, or if the input signal is unrecognized as one of the enable
video formats, the GENLOCK pin should not be set LOW.
The REF_LOST output pin may also be read via bit 0 of the Genlock_Status register (see
Section 3.10.3 on page 67).
3.5.2.1 Ambiguous Standard Selection
There are some standards with identical H, V, and F timing parameters, such that the
GS4901B/GS4900B’s reference format detector cannot distinguish between them.
Table 3-2 groups standards with shared H, V, and F periods. Using the Amb_Std_Sel
register at address 10h of the host interface, the user may select their choice of standard
to be identified with a particular set of measurements. For example, to have 1716 clocks
of 27MHz per line with 525 lines per frame identified as 4fsc 525, program
Amb_Std_Sel[10:0] = XXX10XXXXXX, where ‘X’ signifies ‘don’t care’.
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
43 of 102
Table 3-2: Ambiguous Standard Identification
Number
1
2
3
4
5
6
Standard
H
(27MHz
Clocks)
16_H
(27MHz
Clocks)
V (lines)
F (lines)
Amb_Std_Sel[10:0]
1920x1080/60/2:1 interlace (25)
800
12800
562.5
1125
XXXXXXXXX00
1920x1080/30/PsF (30)
800
12800
562.5
1125
XXXXXXXXX01
1920x1035/60/2:1 interlace (19)
800
12800
562.5
1125
XXXXXXXXX10
1920x1080/59.94/2:1 interlace
(26)
800.8
12813
562.5
1125
XXXXXXX00XX
1920x1080/29.97/PsF (32)
800.8
12813
562.5
1125
XXXXXXX01XX
1920x1035/59.94/2:1 interlace
(20)
800.8
12813
562.5
1125
XXXXXXX10XX
1920x1080/50/2:1 interlace (27)
960
15360
562.4
1125
XXXXX00XXXX
1920x1080/25/PsF (34)
960
15360
562.4
1125
XXXXX01XXXX
601 525 / 2:1 interlace (3)
1716
27456
262.5
525
XXX00XXXXXX
720x486/59.94/2:1 interlace (7)
1716
27456
262.5
525
XXX01XXXXXX
4fsc 525 / 2:1 interlace (1)
1716
27456
262.5
525
XXX10XXXXXX
601 - 18MHz 525/2:1 interlace
(5)
1716
27456
262.5
525
XXX11XXXXXX
601 625 / 2:1 interlace (4)
1728
27648
312.5
625
X00XXXXXXXX
720x576/50/2:1 interlace (8)
1728
27648
312.5
625
X01XXXXXXXX
Composite PAL 625/2:1/25 (2)
1728
27648
312.5
625
X10XXXXXXXX
601 - 18MHz 625/2:1 interlace
(6)
1728
27648
312.5
625
X11XXXXXXXX
RSVD
RSVD
RSVD
RSVD
RSVD
0XXXXXXXXXX
858
13728
525
525
1XXXXXXXXXX
720x483/59.94/1:1 progressive
(9)
‘X’ signifies ‘don’t care.’ The X bit will be ignored when determining which standard to select in each of the 6 groups above.
NOTE: When the SD input reference format of 720x483/59.94/1:1 (VID_STD = 9) is applied to the input, the user must set bit [15] of
the of the Amb_Std_Sel register address to '1' before the device will recognize this reference.
3.5.3 Behaviour on Loss and Re-acquisition of the Reference Signal
By default, the GS4901B/GS4900B will ignore one missing H pulse on the HSYNC pin
and will continue to operate in Genlock mode (although the LOCK_LOST pin will
temporarily be set HIGH). This behaviour is controlled by the Run_Window bits of
register address 24h.
If there are two consecutive missing H pulses on the HSYNC input pin, the REF_LOST
and LOCK_LOST pins will both go HIGH and the device will enter Freeze mode. An
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
44 of 102
internal flywheel ensures the selected output clock and timing signals maintain their
previous phase and frequency and continue to operate without glitches.
The VSYNC and FSYNC signals are not monitored in Genlock mode; loss of signal on
these pins will not affect the operation of the device.
NOTE 1: If the input reference is removed and re-applied, all line-based timing outputs
will be inaccurate for up to one frame for all output standards.
NOTE 2: When locking the SD input reference standards 3, 5, 7, or 9 to the “f/1.001” HD
input reference standards, there may be a random phase difference between the input
VSYNC and output V Sync signals occuring each time the input reference is removed
and re-applied. This will affect all line-based timing outputs. The user may reset the
line-based counters after the reference is re-applied without disrupting the pixel or
audio clocks by toggling bit 15 of register address 83h in the host interface. This will
cause the input VSYNC and line-based timing output signals to take on their default
timing relationship, as described in Note 3 of Section 3.2.1.1 on page 36.
Re-acquisition of the Same Reference
Upon re-application of the reference signal, the device checks whether the reference
has drifted more than +/- 2us from its expected location by comparing the current
relative position of the H pulses with the previous position, over a 16-line interval. If the
reference returns with the H pulses in the expected location +/- 2us, the PLL will drift
lock and the clock generator will continue to operate without a glitch. The REF_LOST
and LOCK_LOST pins will be set back LOW.
If the reference returns with the H pulses outside the +/- 2us window, the device will
crash lock the output timing to the new input phase. The principles of crash lock and
drift lock are described in Section 3.6.1 on page 49.
NOTE: To resume proper genlock operation upon re-application of the reference signal,
the user must implement the following register manipulation every time the reference
is removed and re-applied:
1. Read the value contained in register address 24h
2. Clear the Run_Window bits [2:0] of register 24h
3. Re-write the value read in step 1 to register address 24h.
This procedure will force the device to lock to the reference as described above, but will
maintain the flywheeling capability of the GS4901B/GS4900B should a single missing H
pulse occur in the genlocked state.
To avoid the above procedure, the user may choose to clear the Run_Window bits [2:0]
of register address 24h upon power-up or reset. However, this will disable the
flywheeling feature of the device that allows it to maintain genlock through one missing
input H pulse.
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
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37703 - 4
December 2009
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Acquisition of a New Reference
When a new reference is applied, the device continues to operate in Freeze mode while
the reference format detector checks for validity as described in Section 3.5.2 on page
44. Once validity is detected, the REF_LOST pin is set LOW.
Assuming GENLOCK is LOW, the device will then attempt to genlock the selected output
clock and timing signals to the new input reference. If the output can be automatically
genlocked to the new input reference, LOCK_LOST will go LOW and the device will
re-enter Genlock mode. Otherwise, the LOCK_LOST pin will remain HIGH and the
device will enter Free Run mode.
3.5.4 Allowable Frequency Drift on the Reference
By default, the frequency of the reference H pulse on HSYNC may drift from its expected
value by approximately +/- 0.2% before the internal video PLL loses lock. This tolerance
may be adjusted using the Max_Ref_Delta register at address 1Eh of the host interface.
The encoding scheme is shown in Table 3-3. The default value of the register is Bh.
NOTE: Regardless of the setting of this register, the device will always differentiate
between 59.94Hz and 60Hz reference standards.
Table 3-3: Max_Ref_Delta Encoding Scheme
Register
Setting
Maximum Allowable
Frequency Drift
Register
Setting
Maximum
Allowable
Frequency Drift
0h
+/- 2 -20
8h
+/- 2 -12
1h
+/- 2 -19
9h
+/- 2 -11
2h
+/- 2 -18
Ah
+/- 2 -10
3h
+/- 2 -17
Bh
+/- 2 -9
4h
+/- 2 -16
Ch
+/- 2 -8
5h
+/- 2 -15
Dh
+/- 2 -7
6h
+/- 2 -14
Eh
+/- 2 -6
7h
+/- 2 -13
Fh
+/- 2 -5
The maximum allowable frequency drift is measured as a fraction of the frequency of the
reference H pulse.
3.6 Genlock
When both the REF_LOST output and the GENLOCK input are LOW, the device will
attempt to genlock the output clock and timing signals to the input reference.
NOTE: The user must apply a reference to the input of the device prior to setting
GENLOCK = LOW. If the GENLOCK pin is set LOW and no reference signal is present, the
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
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generated clock and timing outputs of the device may correspond to the internal default
settings of the chip until a reference is applied.
Once reference validity is established and the reference format is recognized, the device
uses an internal cross-reference genlock look-up table to determine whether the input
can be used to genlock the output. A simplified version of this look-up table is shown in
Table 3-4. The table represents a matrix with the VID_STD[5:0] number representation
of each possible reference format along the top axis, and the VID_STD[5:0]
representation of each possible output timing format along the vertical axis. A shaded
box indicates that the output format can be automatically genlocked to the input
reference.
If the device determines that the output can be automatically genlocked to the input
reference, it will lock the output format to the reference, adjust the output timing signals
based on the genlock timing offset registers (Section 3.2.1.1 on page 37), and then set the
LOCK_LOST pin LOW.
If the device cannot automatically genlock the output to the applied reference, the
LOCK_LOST pin will be set HIGH and the device will operate in Free Run mode.
Individual H, V, and F-locked signals can be read from the Genlock_Status register of the
host interface. Additionally, designated bits in the Genlock_Control register may be
configured to permit the genlock block to ignore invalid timing on the HSYNC, VSYNC,
or FSYNC pin when determining the locked status of the device. These registers are
described in Section 3.9.3 on page 66.
The user may disable one or more of the 36 video standards listed in Table 1-2 from
being used to genlock the output by setting the Reference_Standard_Disable register
located at address 11h-13h of the host interface. If a reference is applied that is disabled
in the Reference_Standard_Disable register, the lock process will fail when the
application layer sets GENLOCKb = LOW.
NOTE: If the device is already genlocked to an input reference and the applied standard
is subsequently disabled in the Reference_Standard_Disable register, the device will
remain locked.
By default, the HD video reference formats are disabled in the
Reference_Standard_Disable register and so must be enabled by the user before
attempting to lock to an HD reference. See Section 1.4 on page 19.
Table 3-4: Cross-reference Genlock Table
1
2
3
4
5
6
7
8
9
Input Reference Format
10 11 12 13 14 15 16 17 18 19 20 21 22 23 25 26 27 29 30 31 32 33 34 35 36 37 38
1
3
4
5
6
7
8
9
10
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3.6.1 Adjustable Locking Time
The GS4901B/GS4900B offers two different locking mechanisms to allow the user to
control the PLL lock time and the integrity of the output signal during the locking
process. The locking process is said to take place after the application of the input
reference and before the LOCK_LOST signal is set LOW.
By default, the internal PLL will crash lock. This locking process will ensure a minimum
PLL locking time; however, crash lock will cause the phase of the output clock and
timing signals to jump during the locking process. The crash behaviour of the video PLL
is controlled by the Crash_Time bits of register address 24h.
Alternatively, the user may set bit 1 of register 16h HIGH to force the PLL to drift lock.
Drift lock will increase the locking time of the PLL, but will maintain the signal integrity
of the output clock and timing pulses during the locking process.
As discussed in Section 3.5.3 on page 45, the device will normally drift lock when the
reference is removed and subsequently re-applied during Genlock mode.
3.6.2 Adjustable Loop Bandwidth
The default loop bandwidth of the GS4901B/GS4900B's internal video PLL is 10Hz when
the output video standard is the same as the input reference format. For other
cross-locking combinations, the default loop bandwidth may be smaller than 1Hz or as
large as 30Hz.
The user may adjust the loop bandwidth of both the video and audio PLLs depending on
the input, output, and audio standards selected. Increasing the loop bandwidth will
result in a shorter PLL lock time, but will allow more frequency components of jitter to
be passed to the outputs. Decreasing the loop bandwidth will decrease the output jitter,
but will result in a longer PLL lock time.
3.6.2.1 Loop Bandwidth of the Video PLL
The capacitive component of the filter controlling the video loop bandwidth is
determined by the Video_Cap_Genlock register and the resistive component is
determined by the Video_Res_Genlock register. These two registers are located at
addresses 26h and 27h, respectively, of the host interface.
To determine the setting of Video_Res_Genlock and Video_Cap_Genlock, the following
equations must be solved:
Video_Res_G enlock =
47 + log2( 6 × BW × JITTERIN × H _Feedback_D ivide )
Video_Cap_G enlock ≤ Video_Res_G enlock – 21
where:
BW = the desired video PLL loop bandwidth
JITTERIN = Jitter present on applied HSYNC reference signal, in seconds
H_Feedback_Divide = the numerator of the video PLL divide ratio
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H_Feedback_Divide represents the numerator of the ratio of the output clock frequency
to the frequency of the H reference signal.
For example, to program a loop bandwidth of 25Hz given a 54MHz video clock and a
reference with a 27MHz video clock and 1716 clocks per line, the following steps are
necessary:
1. Calculate H_Feedback_Divide:
H _Feedback_D ivide f pclkout
------------------------------------------------- × -------------------H _Reference_D ivide f Hrefin
f pclkout = 27MHz
H _Feedback_D ivide
1716 1716
∴-------------------------------------------------= 27 × -----------= ----------H _Reference_D ivide
27
1
27
f Hrefin = -----------MHz
1716
Therefore, H_Feedback_Divide = 1716.
2. Calculate the value for Video_Res_Genlock:
Video_Res_G enlock =
–9
47 + log2( 6 × 25 × ( 3 × 10 ) × 1716)
= 37
3. Calculate the value for Video_Cap_Genlock:
Video_Cap_G enlock = 37 – 21 = 16
Therefore, program Video_Res_Genlock = 37 and Video_Cap_Genlock = 16.
NOTE: The value programmed in the Video_Res_Genlock register must be between 32
and 42. The value programmed in the Video_Cap_Genlock register must be greater than
10. These limits define the exact range of loop bandwidth adjustment available.
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3.6.2.2 Loop Bandwidth of the Audio PLL (GS4901B only)
The capacitive component of the filter controlling the audio loop bandwidth is
determined by the Audio_Cap_Genlock register and the resistive component is
determined by the Audio_Res_Genlock register. These two registers are located at
addresses 39h and 3Ah, respectively, of the host interface.
To determine the setting of Audio_Res_Genlock and Audio_Cap_Genlock, the following
equations must be solved:
Audio_Res_G enlock =
47 + log2( 6 × BW × JITTERIN × A _Feedback_D ivide )
Audio_Cap_G enlock ≤ Audio_Res_G enlock – 21
where:
BW = the desired audio PLL loop bandwidth
JITTERIN = Jitter present on output PCLK, in seconds.
A_Feedback_Divide = the numerator of the audio PLL divide ratio
A_Feedback_Divide is defined by the following equation:
fs
A _Feedback_D ivide
-------------------------------------------------- = n × ---------f
A_Reference_D ivide
out
Where fs is the fundamental audio sampling frequency and fout is the output video clock
frequency. The integer constant, n, will depend on the fundamental audio sampling
frequency as shown in Table 3-5.
Table 3-5: Integer Constant Value
ASR_SEL[2:0]=100b
Enable_384fs = 0
Value of constant (n)
NO
X
3072
YES
YES
1024
YES
NO
1536
NOTES:
1. Enable_384fs corresponds to bit 5 of address 31h of the host interface. It is LOW by default.
2. ‘X’ signifies ‘don’t care.’ This bit will be ignored when determining n.
NOTE: The value programmed in the Audio_Res_Genlock register must be between 32
and 42. The value programmed in the Audio_Cap_Genlock register must be greater than
10. These limits define the exact range of loop bandwidth adjustment available.
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3.6.3 Locking to Digital Timing from a Deserializer
As described in Section 3.4.1 on page 41, the GS4901B/GS4900B may be genlocked to
either an analog reference, such as a Black & Burst signal, or to an SDI input via the
digital H, V, and F blanking signals normally produced by a deserializer. When locking
to an SDI input, the user should consider the possibility of a switch of the SDI signal
upstream from the system.
If the GS4901B/GS4900B is locked to the digital H, V, and F blanking signals produced
by a deserializer, and the SDI input to the deserializer is switched such that the phase of
the H input changes abruptly, the REF_LOST output will remain LOW and the
GS4901B/GS4900B will not crash lock to the new H phase. Instead, the clock and timing
outputs will very slowly drift towards the new phase. During this period of drift, the
LOCK_LOST output will be LOW, even though the device is not genlocked.
The user should clear the Run_Window bits [2:0] of register adress 24h to force the
device to crash lock should such a switch occur. This will cause the GS4901B/GS4900B
to crash lock whenever it sees a disturbance of the input H signal.
NOTE: Any action that causes an abrupt phase change of the H input to the
GS4901B/GS4900B such that REF_LOST is not triggered will cause the device to respond
in the manner described above.
In addition to the slow drifting behaviour outlined above, there may also be a random
phase difference between the input VSYNC and output V Sync signals occurring each
time a switch in the SDI stream causes an abrupt phase change of the H input to the
GS4901B/GS4900B. This will only occur when attempting to lock the 525-line SD output
standards to the "f/1.001" HD input reference standards. All line-based timing outputs
are affected.
The only way to ensure a constant phase difference between the input VSYNC signal
and the line-based timing outputs is to reset the line-based counters after such a switch
occurs. This is acheived by toggling bit 15 of register address 83h in the host interface.
The device will then delay all line-based output timing signals by ΔVsync lines relative
to the input VSYNC reference, as described in NOTE 3 of Section 3.2.1.1 on page 36.
3.7 Clock Synthesis
The clock synthesis circuit generates the video clocks based on the VID_STD[5:0] pins
and host register settings. In the GS4901B, the clock synthesis circuit also generates the
audio clock signals based on the ASR_SEL[2:0] pins and host register settings.
The generated video and audio clocks may be further divided and are presented to the
application layer via pins PCLK1-PCLK3 and ACLK1-ACLK3 respectively.
3.7.1 Video Clock Synthesis
The video clock generator is referenced to an internal crystal oscillator and is
responsible for generating the PCLK output signals.
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The crystal oscillator requires an external 27MHz crystal connected to pins X1 and X2,
or can be driven at LVTTL levels from an external 27MHz source connected to X1. These
two configurations are shown in Figure 1-1.
Four different video sample clock rates may be selected using the VID_STD[5:0] pins of
the device. Section 1.4 on page 19 lists the video formats available using the
VID_STD[5:0] pins.
If desired, the external VID_STD[5:0] pins may be ignored by setting bit 1 of the
Video_Control register, and the video standard may instead be selected via the
VID_STD[5:0] register of the host interface (see Section 3.10.3 on page 67). Although the
external VID_STD[5:0] pins will be ignored, they should not be left floating.
Once the video clock has been generated, it will be presented to the application layer via
the PCLK1 to PCLK3 pins. By default, each of the 3 video clock outputs will produce the
generated fundamental clock frequency. However, it is possible to select other rates for
each PCLK output by programming the PCLK_Phase/Divide registers beginning at
address 2Ch of the host interface (see Section 3.10.3 on page 67).
Each PCLK output may be individually programmed to provide one of the following:
•
PCLK fundamental frequency
•
Fundamental frequency /2
•
Fundamental frequency /4
When all six VID_STD[5:0] pins are set LOW, the video clocks will be disabled. PCLK1
and PCLK2 will go LOW and PCLK3/PCLK3 will be high impedance.
NOTE: If the PCLK divider bits of registers 2Ch - 2Eh are set to enable a divide by 2 or
divide by 4, the resultant divided clock will align with the falling edge of the output H
Sync timing signal either on its rising or falling edge.
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The PCLK1 to PCLK3 outputs may also be individually delayed with respect to the eight
TIMING_OUT signals to allow for skew control downstream from the
GS4901B/GS4900B. Using the PCLK_Phase/Divide registers, the phase of each clock
may be delayed up to a nominal 10.3ns in 16 steps of approximately 700ps each
(Table 3-6). This delay is available in addition to the genlock timing offset phase
adjustment described in Section 3.2.1 on page 35.
Table 3-6: Video Clock Phase Adjustment Host Settings
PCLKn_Phase[3:0] Setting
0
h
1h
2h
3h
4h
5h
6h
7h
8h
9h
Ah
Bh
Ch
Dh
Eh
Fh
Phase Increment (ns)
0
0.7
1.4
2.1
2.8
3.5
4.2
4.9
5.6
6.3
7.0
7.7
8.4
9.1
9.8
10.3
NOTES:
1. The phase increments listed above are nominal values.
2. The phase of PCLK is delayed relative to the TIMING_OUT pins.
Additionally, the current drive capability of PCLK1 and PCLK2 may be set high or low
using the PCLK_Phase/Divide registers. By default the current drive will be low.
3.7.2 Audio Clock Synthesis (GS4901B only)
The audio clock generator is referenced to the internal PCLK signal and is responsible for
generating the ACLK output signals. Three audio clock output pins, ACLK1 to ACLK3,
are available to the application layer.
The fundamental sampling frequency, fs, is selected using the ASR_SEL[2:0] pins as
shown in Table 3-7.
If desired, the external ASR_SEL[2:0] pins may be ignored by setting bit 2 of the
Audio_Control register and the sampling frequency may instead be programmed in the
ASR_SEL[2:0] register of the host interface (see Section 3.10.3 on page 67). Although the
external ASR_SEL[2:0] pins will be ignored, they should not be left floating.
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Table 3-7: Audio Sample Rate Select
ASR_SEL[2:0]
Sampling Frequency (kHz)
000
Audio Clock Generation Disabled
001
32
010
44.1
011
48
100
96
101
Slow 32*
110
Slow 44.1*
111
Slow 48*
*Slow 32, 44.1, and 48 are available only when the video standard selected is 23.98, 29.97, or
59.94 frame rate based. They refer to 32kHz, 44.1kHz, or 48kHz multiplied by 1000/1001 to
maintain the 1, 2, or 3 frame sequence normally associated with 24, 30, and 60 fps video.
When all three ASR_SEL[2:0] pins are set LOW, the audio clock outputs will be high
impedance. In this case, the application layer may continue to power the
AUD_PLL_VDD pin; however, to minimize noise and power consumption,
AUD_PLL_VDD may be grounded.
By default, after system reset, ACLK1 to ACLK3 will output clock signals at 256fs, 64fs,
and fs respectively. Different division ratios for each output pin may be selected by
programming the ACLK_fs_Multiple registers beginning at address 3Fh of the host
interface (see Section 3.10.3 on page 67). The encoding of this register is shown in
Table 3-8. Clock outputs of 512fs, 348fs, 256fs, 192fs, 128fs, 64fs, fs, and z bit are
selectable on a pin by pin basis. The z bit will go HIGH for one fs period every 192 fs
periods. Its phase is not defined by any timing event in the GS4901B, and so is arbitrary.
Table 3-8: Audio Clock Divider
ACLKn_fs_Multiple[3:0]
Audio Clock Frequency
000
fs
001
64fs
010
128fs
011
192fs*
100
256fs
101
384fs*
110
512fs**
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Table 3-8: Audio Clock Divider (Continued)
ACLKn_fs_Multiple[3:0]
Audio Clock Frequency
111
z-bit
*This setting is only available when the enable_384fs bit of the Audio_Control register is
HIGH.
**512fs clock will have a 33% duty cycle when the enable_384fs bit is HIGH and fs = 96kHz.
The fs signal on ACLK1-3 has an accurate 50% duty cycle, and can be used for left/right
definition, with the following exception: if fs = 96kHz and the user configures the host
interface such that one of the three ACLK pins is set to output a clock signal at 192fs or
384fs, the 512fs clock will have a 33% duty cycle.
All audio clocks are initially reset on the rising edge of the AFS pulse, ensuring that video
to audio clock synchronization is correct. During normal operation, the audio clock edge
is allowed to drift slightly with respect to the AFS pulse. By default, the audio clock will
be reset directly by the AFS pulse if it drifts more than approximately +/-0.1us from the
rising edge of the AFS pulse. However, after device reset, or after the application of a
new input reference, the ACLK outputs may sometimes be offset from the AFS pulse by
up to several microseconds. The offset will remain until the device is reset or the
reference removed and re-applied. The user may avoid this offset by minimizing the
width of the AFS_Reset_Window using bits 9-7 of register 31h for the duration of the
audio PLL locking process. Once the audio PLL is locked, bit 1 of register 1Fh will be set
HIGH, and the AFS_Reset_Window may be set as desired. See Table 3-9.
Table 3-9: Encoding Scheme for AFS_Reset_Window
Window Tolerance (us)
AFS_Reset_Window
(address 31h)
fs = 32kHz
fs = 44.1kHz
fs = 48 kHz
fs = 96 kHz
(enable_384fs = 1)
fs = 96 kHz
(enable_384fs = 0)
000
0.044
0.033
0.030
0.030
0.044
001
0.084
0.062
0.057
0.057
0.084
010
(default)
0.166
0.121
0.112
0.112
0.166
011
0.329
0.239
0.220
0.220
0.329
1XX
0.654
0.475
0.437
0.437
0.654
NOTE: ‘X’ signifies ‘don’t care.’ The bit setting will be ignored.
3.7.2.1 Audio to Video Clock Phasing
The important aspect of the audio to video phase relates to the way in which the AFS
pulse is used to reset the audio clock dividers so as to line up the leading edge of the
audio clocks with the leading edge of the H Sync pulse on line 1 of the first field in the
audio frame sequence. The AFS pulse is further discussed in Section 3.8.2 on page 59.
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625i 50 Format
For the 48kHz sampling rate, the audio to video phase relationship for 625/50i reference
signals is provided by the device in accordance with the EBU recommended practice
R83-1996. The start of an audio frame (fs clock) will align with the 50% point of the H
sync input of line 1 of each video frame (+/- the allowable drift specified in Table 3-9).
525i 59.94 Format
For 525/59.94 NTSC reference signals, the device will observe the 5-frame
phase-relationship inherent with this video standard, aligning the audio clocks with the
50% point of the H sync input of line 1 on every fifth frame (+/- the allowable drift
specified in Table 3-9).
The number of audio sample clocks during a video frame is shown in Table 3-10 for 32,
44.1, and 48kHz audio sampling frequencies.
Table 3-10: Audio Sampling Frequency to Video Frame Rate Synchronization
Audio Samples per Video Frame
Audio Sample Rate (kHz)
24fps
25fps
29.97fps
30fps
50fps
59.94fps
60fps
32
4000/3
1280
16016/15
3200/3
640
8008/15
1600/3
44.1
3675/2
1764
147147/100
1470
882
147147/200
735
48
2000
1920
8008/5
1600
960
4004/5
800
* fps = frames per second.
The external 10FID input pin may be used to resynchronize other audio clock
frequencies, according to Table 3-10, by applying an active signal during the reference
HSYNC of line 1 of the appropriate video frame. Please see Section 3.4.2 on page 42 for
more details on the 10FID input pin.
In the case where 10FID is not present as a reference signal, the GS4901B will
automatically generate an AFS pulse appropriate to the format selected, and use it to
create an audio frame sequence.
Host Interface Control of AFS and 10FID
Alternatively, the user may program the device via the host interface to re-time the
audio frame sequence and 10 field-ID. Using register 1Ah, a pulse may be generated to
reset the AFS and/or 10FID dividers at the start of an output video frame (see
Section 3.10.3 on page 67).
If using the host interface to reset the AFS pulse, the device may be configured to ignore
the input 10FID reference pin. To disable the signal on the external 10FID pin from
resetting the AFS output pulse, set bit 0 of the Audio_Control register HIGH.
If using the host interface to reset the 10FID pulse, the external 10FID pin must be
grounded.
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3.8 Video Timing Generator
The internal PCLK signal generated by the clock synthesis circuit is used to produce
horizontal, vertical, and frame based timing output signals.
The signals generated and available to the application layer via the TIMING_OUT pins
are: H Sync, H Blanking, V Sync, V Blanking, F Sync, F Digital, DE, 10FID, AFS (GS4901B
only), and USER_1~4. These signals are defined in Section 1.5 on page 23. Additional
information pertaining to the 10FID, AFS, and USER_1~4 signals can be found in the
sub-sections below.
When the GS4901B/GS4900B is operating in Genlock mode, the H, V, and F based output
timing signals are synchronized to the H, V, and F reference signals applied to the inputs
by the application layer. The video timing outputs may be offset from the input
reference by programming the Genlock Offset registers beginning at address 1Bh of the
host interface (see Section 3.2.1.1 on page 36).
All TIMING_OUT signals have selectable polarity. The default polarities for each signal
are given in the descriptions in Section 1.5 on page 23.
3.8.1 10 Field ID Pulse
As described in Table 1-3, the 10 field ID (10FID) output signal is used in the
identification of film to video cadence. It is only generated for 29.97, 30, 59.94, and 60fps
formats.
The 10FID pulse is generated on every 5th frame for 29.97 and 30fps formats, and every
10th frame on 59.94 and 60fps formats.
By default, the 10FID signal is set HIGH on the leading edge of the H Sync output for the
duration of line 1 of field 1 at the start of the 10 field sequence. This is shown in
Figure 3-6.
Alternatively, by setting bit 4 of the Video_Control register at address 4Ch of the host
interface, the 10FID output signal may be configured to go HIGH (default polarity) on the
leading edge of the H Sync pulse of line 1 of the first field in the 10 field sequence, and
be reset LOW on the leading edge of the H Sync pulse of line 1 of the second field in the
10 field sequence. This is shown in Figure 3-7.
Total Line
10FID Output
Line 1, Frame 1 every 'n' frames
Horizontal Sync Output
Line 1 every n frames where:
n = 5 @ 29.97 fps, 30 fps
n = 10 @ 59.94 fps, 60 fps
Figure 3-6: Default 10FID Output Timing
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Total Field
10FID Output
Horizontal Sync Output
Line 1 every n frames where:
n = 5 @ 29.97 fps, 30 fps
n = 10 @ 59.94 fps, 60 fps
Figure 3-7: Optional 10FID Output Timing
The phasing of the divide by n frame counter may be reset by an external pulse on the
10FID input pin, or via register 1Ah of the host interface (see Section 3.10.3 on page 67).
NOTE: If a 10FID input signal is not provided to the device, the 10FID output signal will
be invalid until the user initiates a reset via the host interface. The user should also reset
the 10FID signal via the host if at any time the H input reference signal is removed and
then re-applied.
3.8.2 Audio Frame Synchronizing Pulse (GS4901B only)
As described in Table 1-3, the audio frame synchronizing (AFS) pulse identifies the
frame, within an n frame sequence, in which the audio sample rate clock is aligned with
the H Sync of line 1. It is generated for all video formats.
The leading edge of the AFS output pulse is co-timed with the H Sync corresponding to
line 1 of every nth frame in the sequence, and therefore identifies the exact time at which
the audio sample rate clock and video PCLK have synchronous leading edges.
The number of frames in the sequence, n, is determined by the video frame rate and the
audio clock frequency. These are selected using the VID_STD[5:0] and ASR_SEL[2:0]
pins or via the host interface.
By default, the AFS pulse is 1 line long, as shown in Figure 3-8. Alternatively, by setting
bit 1 of the Audio_Control register, the AFS output signal may be configured to go HIGH
on the leading edge of the H Sync pulse of line 1 of the first field in the ‘n’ frame
sequence, and be reset LOW on the leading edge of the H Sync pulse of line 1 of the
second field in the sequence. The AFS timing in this configuration is similar to the 10FID
optional timing shown in Figure 3-7.
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Total Line
AFS_OUT
Horizontal Sync Output
Line 1 every n frames where:
n = 1 @ 25fps: fs = 32kHz
n = 1 @ 25fps, 30fps & 60fps: fs = 44.1kHz
n = 1 @ 25fps, 30fps & 60fps; fs = 48kHz
n = 2 @ 24fps; fs = 44.1kHz, 48kHz
n = 3 @ 24fps, 30fps & 60fps: fs = 32kHz
n = 5 @ 29.97fps & 59.94fps; fs = 48kHz
n = 15 @ 29.97fps & 59.94fps; fs = 32kHz
n = 100 @ 29.97fps; fs = 44.1kHz
n = 200 @ 59.94fps; fs = 44.1kHz
Figure 3-8: AFS Output Timing
The phasing of the divide by n counter can be controlled by the 10FID input or via
designated registers in the host interface.
By default, the 10FID input pin controls the AFS phase (in addition to controlling the
10FID phase); however, this feature may be disabled by setting bit 0 of the
Audio_Control register (see Section 3.10.3 on page 67). In addition, the AFS signal may
be reset via register 1Ah.
3.8.3 USER_1~4
As described in Table 1-3, the GS4901B/GS4900B offers 4 user programmable output
signals which are available independent of the selected output video format.
Each user signal is individually programmable and the polarity, position, and width of
each output may be defined with respect to the digital output timing of the device. Each
output signal may be programmed in both the horizontal and vertical dimensions
relative to the leading edges of H Blanking and V Blanking. If desired, the pulses
produced may then be combined with a logical AND, OR, or XOR function to produce a
composite signal (for example, a horizontal back porch pulse during active lines only, or
the active part of lines 15 through 20 for vertical information retrieval).
By default, the AND, OR, and XOR functions are disabled. Therefore, when a USER signal
is selected using the Output_Select registers of the host interface, the signal will go LOW
(default polarity) at the H_Start pixel and return HIGH after the H_Stop pixel. Setting the
AND bit HIGH, for example, will cause the USER signal to be active only when USER_H
is active and USER_V is active (i.e. the pixel is between both H_Start and H_Stop and
V_Start and V_Stop). See Figure 3-9.
NOTE: The effective horizontal range of the four user-defined timing signals is [H_Start
+ 1, H_Stop], except when H_Start = 1, in which case the range is [H_Start, H_Stop]. This
prevents the user from specifying an output USER signal that begins on pixel 2 of a line.
In the case of interlaced output formats, the programmed vertical start and stop lines
refer to the start and stop lines of the generated USER signal on the odd fields. The start
GS4901B/GS4900B SD Clock and Timing Generator
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and stop lines of the USER signal on the even fields will be V_Start - 1 and V_Stop - 1,
respectively.
For example, if VID_STD[5:0] = 3, the odd fields will have 263 lines and the even fields
will have 262 lines. A user-defined vertical pulse programmed to start on line 12 and
stop on line 17 will start on frame lines 12 and 274, and stop on frame lines 17 and 279.
V_Start
V_Start
V_Stop
V_Stop
V_Start
V_Start
V_Stop
V_Stop
AND=0, OR=1
H_Stop
H_Start
AND=1
H_Stop
H_Start
AND=0, OR=0, XOR=0 (default)
H_Stop
H_Start
H_Stop
H_Start
The designated registers for programming each user signal are located in the host
interface beginning at address 57h. See Section 3.10.3 on page 67.
AND=0, OR=0, XOR=1
Shading indicates when USER_x signal is active
Figure 3-9: USER Programmable Output Signal
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3.8.4 TIMING_OUT Pins
The horizontal, vertical, and frame based timing output signals for the selected video
format are available to the application layer via the TIMING_OUT_1 to TIMING_OUT_8
pins.
Programmable Crosspoint Switch
Each TIMING_OUT pin outputs a default signal as shown in Table 1-3. Alternatively, a
crosspoint switch may be programmed via the eight Output_Select registers of the host
interface, allowing the user to select which output signal is directed to each
TIMING_OUT pin (see Section 3.10.3 on page 67). Any signal may be sent to more than
one pin if desired.
Table 3-11 outlines the encoding scheme of the eight Output_Select registers, which
begin at address 43h of the host interface.
Table 3-11: Crosspoint Select
Output_Select_n Bit Settings
Output Signal
0000
High Impedance
0001
H Sync
0010
H Blanking
0011
V Sync
0100
V Blanking
0101
F Sync
0110
F Digital
0111
10FID
1000
DE
1001
Reserved
1010
AFS*
1011
USER_1
1100
USER_2
1101
USER_3
1110
USER_4
1111
Reserved
*AFS is only available on the GS4901B. The bit setting 1010b will be ignored by the GS4900B.
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3.8.4.1 Selectable Current Drive and Polarity
The current-drive of each timing output pin is also selectable via the Output_Select
registers. The current drive of each TIMING_OUT pin is low by default. However, it may
be set high to accommodate certain applications.
Additionally, the Polarity register of the host interface may be programmed to select the
polarity of each timing output signal.
3.9 Extended Audio Mode for HD Demux using the Gennum Audio
Core
The GS4901B/GS4900B has been designed to interface with Gennum's FPGA Audio
Core in order to provide a 24.576MHz clock (512 * 48kHz) locked to the audio clock
contained in the embedded audio data packets of an HD-SDI stream. It is the
responsibility of the user to divide this clock by 4 to obtain the 6.144MHz required by the
core.
In HD Demux mode, the FPGA Audio Core will extract an audio clock from the
embedded audio data packets and present a 24kHz clock to the GS4901B/GS4900B via
the aclkdiv2a (for Group A) and aclkdiv2b (for Group B) outputs. The embedded clock
must be 48kHz.
The 24kHz reference signals for each audio group must be applied to the HSYNC input
pin of a GS4901B/GS4900B, while a divided version of this signal must be applied to the
VSYNC input pin. The divided signal must meet the requirements for VSYNC validity
given in Section 3.5.2 on page 44. It is recommended that the VSYNC signal be generated
by dividing the 24kHz reference applied to HSYNC by 512 to give 46.875Hz.
To enable the extended audio mode, the user must do the following:
1. Set VID_STD[5:0] = 4d.
2. Set the F_Lock_Mask and V_Lock_Mask bits [4:3] of register address 16h to 1.
3. Set the Ext_Audio_Mode register address 81h to 20C1h.
4. Toggle bit [6] of register address 16h.
In this mode, the GS4901B/GS4900B will produce a 24.576MHz clock on its PCLK output
pins that is locked to the 24kHz extracted audio clock reference applied to HSYNC. It
will not lock to any other reference frequency. The user may then divide this frequency
by 4 using the programmable dividers in the GS4901B/GS4900B.
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FPGA
Serial
Video
Input
Video Data
GS1559
Deserializer
PCLK
vin[19:0]
aclk64a
wclka
pclk
aout1_2
aout3_4
/512
/512
GS49xxB
PCLK1
aclk128a
HD AUDIO
DEMUX CORE
aclk64b
wclkb
aout5_6
GS49xxB
PCLK1
aclk128b
aout7_8
aclkdiv2b
aclkdiv2a
Figure 3-10: Audio Clock Block Diagram for HD Demux Operation
3.10 GSPI Host Interface
The GSPI, or Gennum Serial Peripheral Interface, is a 4-wire interface provided to allow
the host to enable additional features of the GS4901B/GS4900B and/or to provide
additional status information through configuration registers in the device.
The GSPI comprises a serial data input signal, SDIN, a serial data output signal, SDOUT,
an active low chip select, CS, and a burst clock, SCLK. The burst clock must have a duty
cycle between 40% and 60%.
Because these pins are shared with the JTAG interface port, an additional control signal
pin, JTAG/HOST is provided. When JTAG/HOST is LOW, the GSPI interface is enabled.
When operating in GSPI mode, the SCLK, SDIN, and CS signals are provided by the
application interface. The SDOUT pin is a non-clocked loop-through of SDIN and may
be connected to the SDIN pin of another device, allowing multiple devices to be
connected to the GSPI chain. The interface is illustrated in Figure 3-11.
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with GENLOCK
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Application Host
GS4911B/GS4910B
SCLK
CS1
SDOUT
SCLK
CS
SDIN
SDOUT
GS4911B/GS4910B
SCLK
CS2
CS
SDIN
SDIN
SDOUT
Figure 3-11: GSPI Application Interface Connection
All read or write access to the GS4901B/GS4900B is initiated and terminated by the host
processor. Each access always begins with a 16-bit command word on SDIN indicating
the address of the register of interest. This is followed by a 16-bit data word on SDIN in
write mode, or a 16-bit data word on SDOUT in read mode.
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3.10.1 Command Word Description
The command word consists of 16 bits transmitted MSB first and includes a read/write
bit, an Auto-Increment bit and a 12-bit address. Figure 3-12 shows the command word
format and bit configurations.
Command words are clocked into the GS4901B/GS4900B on the rising edge of the serial
clock, SCLK, which operates in a burst fashion.
When the Auto-Increment bit is set LOW, each command word must be followed by
only one data word to ensure proper operation. If the Auto-Increment bit is set HIGH,
the following data word will be written into the address specified in the command word,
and subsequent data words will be written into incremental addresses. This facilitates
multiple address writes without sending a command word for each data word.
Auto-Increment may be used for both read and write access.
MSB
R/W RSV
LSB
RSV
AutoInc
A11
A10
A9
RSV = Reserved. Must be set to zero.
A8
A7
A6
A5
A4
A3
A2
A1
A0
R/W: Read command when R/W = 1
Write command when R/W = 0
Figure 3-12: Command Word Format
MSB
D15
LSB
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
Figure 3-13: Data Word Format
3.10.2 Data Read and Write Timing
Read and write mode timing for the GSPI interface is shown in Figure 3-14 and
Figure 3-15 respectively. The timing parameters are defined in Table 3-12.
When several devices are connected to the GSPI chain, only one CS should be asserted
during a read sequence.
During the write sequence, all command and following data words input at the SDIN pin
are output at the SDOUT pin as is. Where several devices are connected to the GSPI
chain, data can be written simultaneously to all the devices that have CS set LOW.
Table 3-12: GSPI Timing Parameters
Parameter
Definition
Specification
t0
The minimum duration of time chip select, CS, must be
LOW before the first SCLK rising edge.
1.5 ns
t1
The minimum SCLK period.
100 ns
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Table 3-12: GSPI Timing Parameters (Continued)
Parameter
Definition
Specification
t2
Duty cycle tolerated by SCLK.
40% to 60%
t3
Minimum input setup time.
1.5 ns
t4
The minimum duration of time between the last SCLK
command word (or data word if the Auto-Increment
bit is HIGH) and the first SCLK of the data word (write
cycle).
37.1 ns
t5
The minimum duration of time between the last SCLK
command word (or data word if the Auto-Increment
bit is HIGH) and the first SCLK of the data word (read
cycle).
148.4 ns
t6
Minimum output hold time (15pF load).
1.5 ns
t7
The minimum duration of time between the last SCLK
of the GSPI transaction and when CS can be set HIGH.
37.1 ns
t8
Minimum input hold time.
1.5 ns
t5
SCLK
t6
CS
SDIN
R/W
RSV
RSV
AutoInc
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
SDOUT
R/W
RSV
RSV
AutoInc
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D3
D4
D1
D2
D0
Figure 3-14: GSPI Read Mode Timing
t0
t7
t4
t1
SCLK
t3
CS
t2
t8
SDIN
R/W
RSV
RSV
AutoInc
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
SDOUT
R/W
RSV
RSV
AutoInc
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
Figure 3-15: GSPI Write Mode Timing
3.10.3 Configuration and Status Registers
Table 3-13 summarizes the GS4901B/GS4900B's internal status and configuration
registers.
All registers are available to the host via the GSPI and are all individually addressable.
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with GENLOCK
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Table 3-13: Configuration and Status Registers
Register Name
Address
Bit
Description
R/W
Default
RSVD
00h - 09h
–
Reserved.
–
–
H_Period
0Ah
15-0
Contains the number of 27MHz pulses in the input
H Sync period. This register is set by the Reference
Format Detector block using the H Sync signal
present on the external HSYNC input pin.
R
N/A
R
N/A
R
N/A
R
N/A
R
N/A
NOTE: If the reference is removed this register will
remain unchanged until a new reference with a
different HSYNC period is applied.
Reference: Section 3.5.1 on page 43
H_16_Period
0Bh
15-0
Contains the number of 27MHz pulses in 16 H Sync
periods. This register is set by the Reference Format
Detector block using the H Sync signal present on
the external HSYNC input pin. It is useful for 1/1.001
data detection.
NOTE: If the reference is removed this register will
remain unchanged until a new reference with a
different HSYNC period is applied.
Reference: Section 3.5.1 on page 43
V_Lines
0Ch
15-0
Contains the number of H Sync periods in the input
V Sync interval. This register is set by the Reference
Format Detector block using the signals present on
the external HSYNC and VSYNC input pins.
NOTE: If the reference is removed this register will
remain unchanged until a new reference with a
different VSYNC period is applied.
Reference: Section 3.5.1 on page 43
V_2_Lines
0Dh
15-0
Contains the number of H Sync periods in 2 V Sync
intervals. This register is set by the Reference
Format Detector block using the signals present on
the external HSYNC and VSYNC input pins.
NOTE: If the reference is removed this register will
remain unchanged until a new reference with a
different VSYNC period is applied.
Reference: Section 3.5.1 on page 43
F_Lines
0Eh
15-0
Contains the number of H Sync periods in the input
F Sync interval. This register is set by the Reference
Format Detector block using the signals present on
the external HSYNC and FSYNC input pins.
NOTE: If the reference is removed this register will
remain unchanged until a new reference is applied.
If the new reference does not include an FSYNC
pulse, this register will be set to zero.
Reference: Section 3.5.1 on page 43
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Table 3-13: Configuration and Status Registers (Continued)
Register Name
Address
Bit
Description
R/W
Default
Input_Standard
0Fh
15-13
Reserved. Set these bits to zero when writing to
0Fh.
–
–
0Fh
12
Force_Input - Set this bit HIGH to force the
GS4901B/GS4900B to recognize the applied input
reference format as the standard programmed in
bits 11-6 of this register.
R/W
0
0Fh
11-6
Forced_Standard - When bit 12 is set HIGH, the
GS4901B/GS4900B will use the value programmed in
these bits, rather than the value in bits 5-0, to
determine the input reference format. The 6-bit
value programmed here should always correspond
to the VID_STD[5:0] value of the applied reference.
R/W
0
R/W
N/A
These bits should not be programmed for normal
operation.
0Fh
5-0
Detected_Standard - Contains the video standard
applied to the input reference pins once it has been
detected. These bits are set by the Reference
Format Detector block and correspond to the
VID_STD[5:0] value of the standard as listed in
Table 1-2.
The Detected_Standard bits will be set to zero if no
input reference signal is applied or if the input
reference signal is not an automatically recognized
video format. Otherwise the value will be between
1 and 54.
Reference: Section 3.5.2 on page 44
Amb_Std_Sel
10h
15-11
Reserved. Set these bits to zero when writing to
10h.
–
–
10h
10-0
The user may set this register to distinguish
between different formats that look identical to the
internal Reference Format Detector block. See
Table 3-2.
R/W
0
Reference: Section 3.5.2.1 on page 44
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Table 3-13: Configuration and Status Registers (Continued)
Register Name
Address
Bit
Description
R/W
Default
Reference_Standard_Disable
13h-11h
38-0
The Reference_Standard_Disable register may be
used to disable/enable one or more of the input
standards given in Table 1-2 from being recognized
by the device and used to genlock the output. This
is done by setting the bit HIGH that corresponds to
the VID_STD[5:0] value of the video format.
R/W
FFFFh
FFFFh
F800h
–
–
For example, if bit 5 is set HIGH, then the output
clock and timing signals will not genlock to an input
reference with timing corresponding to
VID_STD[5:0] = 5 in Table 1-2.
Likewise, to enable recognition of VID_STD[5:0] =
26 (1080i/59.94) as an input reference format, the
user must set bit 26 LOW.
Address 13h = bits 38-32*
Address 12h = bits 31-16
Address 11h = bits 15-0
*Bits 47-39 of address 13h should always be written
HIGH.
Reference: Section 3.5 on page 43
RSVD
14h
–
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Reserved
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Table 3-13: Configuration and Status Registers (Continued)
Register Name
Address
Bit
Description
R/W
Default
Genlock_Status
15h
15-6
Reserved.
–
–
15h
5
Reference_Lock - this bit will be HIGH when the
output is successfully genlocked to the input (i.e.
when bits 4-1 of this register are HIGH and are not
masked by bits 4-2 of register 16h).
R
N/A
R
N/A
R
N/A
R
N/A
R
N/A
R
N/A
The LOCK_LOST output pin is an inverted copy of
this bit.
Reference: Section 3.6.1 on page 49
15h
4
F_Lock - this bit will be HIGH when the output F is
successfully genlocked to the FSYNC input.
NOTE: If the input reference does not include an
FSYNC input, this bit will have the same setting as
V_Lock (bit 3).
Reference: Section 3.6.1 on page 49
15h
3
V_Lock - this bit will be HIGH when the output V is
successfully genlocked to the VSYNC input.
Reference: Section 3.6.1 on page 49
15h
2
H_Lock - this bit will be HIGH when the output H is
successfully genlocked to the HSYNC input.
Reference: Section 3.6.1 on page 49
15h
1
Clock_Lock - this bit will be HIGH when the video
clock is locked to the internal V_pll AND the audio
clock is locked to the internal A_pll (i.e. bits 0 and 1
of register 1Fh are HIGH).
Reference: Section 3.6.1 on page 49
15h
0
Reference_Present - this bit will be HIGH when a
valid input reference signal has been applied to the
device. The REF_LOST output pin is an inverted copy
of this bit.
Reference: Section 3.5.2 on page 44
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Table 3-13: Configuration and Status Registers (Continued)
Register Name
Address
Bit
Description
R/W
Default
Genlock_Control
16h
15-7
Reserved. Set these bits to zero when writing to
16h.
–
–
16h
6
This bit is used to enable the Extended Audio Mode
of the device.
R/W
0
16h
5
Genlock_From_Host - set this bit HIGH to enable
video genlock control via the Host Interface instead
of the external GENLOCK pin (see bit 0 of this
register).
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
–
–
Reference: Section 3.2 on page 35
16h
4
F_Lock_Mask - if this bit is set HIGH, the
GS4901B/GS4900B will ignore the status of F_Lock
(bit 4 of register 15h) when determining the status
of Reference_Lock (bit 5 of register 15h).
Reference: Section 3.6.1 on page 49
16h
3
V_Lock_Mask - if this bit is set HIGH, the
GS4901B/GS4900B will ignore the status of V_Lock
(bit 3 of register 15h) when determining the status
of Reference_Lock (bit 5 of register 15h).
Reference: Section 3.6.1 on page 49
16h
2
H_Lock_Mask - if this bit is set HIGH, the
GS4901B/GS4900B will ignore the status of H_Lock
(bit 2 of register 15h) when determining the status
of Reference_Lock (bit 5 of register 15h).
Reference: Section 3.6.1 on page 49
16h
1
Drift_Crash - when this bit is set HIGH, the
generated video clock will drift lock to a new input
reference rather than crash lock.
Reference: Section 3.6.1 on page 49
16h
0
GENLOCK - this bit may be used instead of the
external pin to Genlock the output video format to
the input reference. This bit will be ignored if bit 5
of this register is LOW.
Reference: Section 3.2 on page 35
RSVD
17h-19h
–
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Reserved
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Table 3-13: Configuration and Status Registers (Continued)
Register Name
Address
Bit
Description
R/W
Default
10FID_AFS_Reset
1Ah
15-4
Reserved. Set these bits to zero when writing to
1Ah.
–
–
1Ah
3
AFS_Reset (GS4901B only) - set this bit HIGH to use
Reset_Sync (bit 0 of register 1Ah) to reset the
output AFS pulse.
R/W
0
R/W
0
NOTE: This bit will remain LOW in the GS4900B. Set
this bit LOW when writing to address 1Ah of the
GS4900B.
Reference: Section 3.7.2.1 on page 56
1Ah
2
10FID_Reset - set this bit HIGH to use Reset_Sync (bit
0 of register 1Ah) to reset the output 10FID pulse.
NOTE: If a 10FID input signal is not provided to the
device, the user must generate a reset using this bit
to initiate the 10FID timing output. In this case, the
10FID input pin must be grounded.
Reference: Section 3.7.2.1 on page 56
1Ah
1
Reserved. Set this bit to zero when writing to 1Ah.
–
–
1Ah
0
Reset_Sync - resets the pulses described in bits 2,
and 3 above.
R/W
0
R/W
0
The reset pulse is generated if this bit is pulsed
(LOW to HIGH to LOW) during the output frame
immediately prior to the frame the reset is to occur.
This reset will operate independently of any other
resets, for example from the reference input.
H_Offset
1Bh
15-0
The output H signal may be delayed with respect to
the input reference by the number of pixels
programmed in this register. (See Section 3.2.1.1 on
page 36).
The value programmed in this register should not
exceed the maximum number of clock periods per
line of the outgoing standard. Horizontal advances
may be achieved by programming a value equal to
the maximum allowable offset minus the desired
advance.
NOTE: This register is internally read by the device
once per field. At that time any new value
programmed is sent to the internal offset circuitry.
Reference: Section 3.2.1.1 on page 36
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Table 3-13: Configuration and Status Registers (Continued)
Register Name
Address
Bit
Description
R/W
Default
V_Offset
1Ch
15-0
The output V signal may be delayed with respect to
the input reference by the number of lines
programmed in this register. (See Section 3.2.1.1 on
page 36).
R/W
0
R/W
0
R/W
000Bh
The value programmed in this register should not
exceed the maximum number of lines per frame of
the outgoing standard. Vertical advances may be
achieved by programming a value equal to the
maximum allowable offset minus the desired
advance.
NOTE: This register is internally read by the device
once per field. At that time any new value
programmed is sent to the internal offset circuitry.
Reference: Section 3.2.1.1 on page 36
Clock_Phase_Offset
1Dh
15-0
Phase_Offset - The output clock and data phase may
be offset with respect to the input reference by the
number of increments programmed in this register.
The increment step size depends on the video clock
frequency.
The encoding scheme for this register is shown in
Table 3-1.
NOTE: This register must be cleared to achieve a
clock phase offset of zero.
Reference: Section 3.2.1.1 on page 36
Max_Ref_Delta
1Eh
15-0
The value programmed in this register controls the
allowed deviance from the expected frequency on
the reference HSYNC before the internal video PLL
loses lock. The encoding scheme is shown in
Table 3-3.
Reference: Section 3.5.4 on page 47
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with GENLOCK
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Table 3-13: Configuration and Status Registers (Continued)
Register Name
Address
Bit
Description
R/W
Default
Video_Status
1Fh
15-5
Reserved.
–
–
1Fh
4
Ref_H_Polarity - status register to indicate the
detected H Sync polarity ('1' for positive, '0' for
negative).
R
N/A
R
N/A
R
N/A
R
N/A
R
N/A
–
–
This bit will be zero when no reference signal is
present.
Reference: Section 3.4.3 on page 42
1Fh
3
Ref_V_Polarity - status register to indicate the
detected V Sync polarity ('1' for positive, '0' for
negative).
This bit will be zero when no reference signal is
present and for digital blanking input references.
Reference: Section 3.4.3 on page 42
1Fh
2
Ref_Blank_Timing - status register to indicate the
input detection of H blanking vs. H sync timing (‘1’
for blanking, '0' for sync timing).
This bit will be zero when no reference signal is
present.
Reference: Section 3.4.3 on page 42
1Fh
1
A_pll_Lock (GS4901B only)- this bit will be HIGH
when the generated audio clock is locked to the
video clock reference.
NOTE: This bit will remain high in the GS4900B.
Reference: bit 1 of register 15h.
1Fh
0
V_pll_Lock - this bit will be HIGH when the
generated video clock is locked to the H Sync input
reference.
Reference: bit 1 of register 15h.
RSVD
20h-23h
–
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
Reserved
74 of 102
Table 3-13: Configuration and Status Registers (Continued)
Register Name
Address
Bit
Description
R/W
Default
Constcf_Genlock
24h
15-8
Crash_Time - controls the crash lock period of video
PLL locking process. This time contributes to the
total PLL Lock Time given in the AC Characteristics
Table.
R/W
–
R/W
–
R/W
–
The time of the crash process in H reference periods
is determined by [Crash_Time x 4] + 1.
The default value of these bits will vary depending
on the output video standard selected.
Reference: Section 3.6.1 on page 49
24h
7-3
Lock_Lost_Threshold - controls the threshold of the
lock indication circuit. A larger value programmed
in this register can increase the stability of the
LOCK_LOST output signal when the input H
reference signal is subject to large amounts of low
frequency jitter. A larger value in this register will
also increase the lock indication time, although not
the actual lock time of the device.
The default value of these bits will vary depending
on the output video standard selected.
24h
2-0
Run_Window - controls the output frequency error
in the case of a missing or mis-timed H reference
transition. The default value of this register allows
the device to maintain genlock through one missing
input H pulse.
This feature can be disabled by programming
Run_Window = 000b. In this case, the device will
immediately react to any disturbance of the input H
signal.
The default value of these bits will vary depending
on the output video standard selected.
Reference: Section 3.5.3 on page 45
RSVD
25h
–
Reserved.
–
–
Video_Cap_Genlock
26h
15-6
Reserved. Set these bits to zero when writing to
26h.
–
–
26h
5-0
Control signal to adjust loop bandwidth of video
genlock block.
R/W
–
The value programmed in this register must be
between 10 and Video_Res_Genlock - 21.
The default value of this register will vary
depending on the output video standard selected.
Reference: Section 3.6.2 on page 49
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
75 of 102
Table 3-13: Configuration and Status Registers (Continued)
Register Name
Address
Bit
Description
R/W
Default
Video_Res_Genlock
27h
15-6
Reserved. Set these bits to zero when writing to
27h.
–
–
27h
5-0
Control signal to adjust loop bandwidth of video
genlock block.
R/W
–
The value programmed in this register must be
between 32 and 42.
The default value of this register will vary
depending on the output video standard selected.
Reference: Section 3.6.2 on page 49
RSVD
28h-2Bh
–
Reserved
–
–
PCLK1_Phase/Divide
2Ch
15-7
Reserved. Set these bits to zero when writing to
2Ch.
–
–
2Ch
6
Current_P1 - selects the current drive capability of
the PCLK1 pin. Set this bit HIGH for high current
drive. Otherwise, the current drive will be low.
R/W
0
R/W
0
R/W
0
R/W
0
Reference: Section 3.7.1 on page 52
2Ch
5-2
PCLK1_Phase - adjusts the output phase of the
PCLK1 clock with respect to the timing output pins.
Phase is delayed in 700ps (nominal) increments as
shown in Table 3-6.
Reference: Section 3.7.1 on page 52
2Ch
1
Divide_By_4 - set this bit HIGH to divide the output
PCLK1 by four.
NOTE: Setting this bit and bit 0 simultaneously HIGH
will hold the PCLK1 pin LOW.
Reference: Section 3.7.1 on page 52
2Ch
0
Divide_By_2 - set this bit HIGH to divide the output
PCLK1 by two.
NOTE: Setting this bit and bit 1 simultaneously HIGH
will hold the PCLK1 pin LOW.
Reference: Section 3.7.1 on page 52
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
76 of 102
Table 3-13: Configuration and Status Registers (Continued)
Register Name
Address
Bit
Description
R/W
Default
PCLK2_Phase/Divide
2Dh
15-7
Reserved. Set these bits to zero when writing to
2Dh.
–
–
2Dh
6
Current_P2 - selects the current drive capability of
the PCLK2 pin. Set this bit HIGH for high current
drive. Otherwise, the current drive will be low.
R/W
0
R/W
0
R/W
0
R/W
0
Reference: Section 3.7.1 on page 52
2Dh
5-2
PCLK2_Phase - adjusts the output phase of the
PCLK2 clock with respect to the timing output pins.
Phase is delayed in 700ps (nominal) increments as
shown in Table 3-6.
Reference: Section 3.7.1 on page 52
2Dh
1
Divide_By_4 - set this bit HIGH to divide the output
PCLK2 by four.
NOTE: Setting this bit and bit 0 simultaneously HIGH
will hold the PCLK2 pin LOW.
Reference: Section 3.7.1 on page 52
2Dh
0
Divide_By_2 - set this bit HIGH to divide the output
PCLK2 by two.
NOTE: Setting this bit and bit 1 simultaneously HIGH
will hold the PCLK2 pin LOW.
Reference: Section 3.7.1 on page 52
PCLK3_Phase/Divide
2Eh
15-6
Reserved. Set these bits to zero when writing to
2Eh.
–
–
2Eh
5-2
PCLK3_Phase - adjusts the output phase of the
PCLK3/PCLK3 clock with respect to the timing
output pins. Phase is delayed in 700ps (nominal)
increments as shown in Table 3-6.
R/W
0
R/W
0
R/W
0
Reference: Section 3.7.1 on page 52
2Eh
1
Divide_By_4 - set this bit HIGH to divide the output
PCLK3/PCLK3 by four.
Setting this bit and bit 0 simultaneously HIGH will
give the full rate video clock on the PCLK3 / PCLK3
pins.
Reference: Section 3.7.1 on page 52
2Eh
0
Divide_By_2 - set this bit HIGH to divide the output
PCLK3/PCLK3 by two.
Setting this bit and bit 1 simultaneously HIGH will
give the full rate video clock on the PCLK3 / PCLK3
pins.
Reference: Section 3.7.1 on page 52
PCLK3_Tristate
2Fh
15-2
Reserved. Set these bits to zero when writing to
2Fh.
–
–
2Fh
1-0
Set these bits to 11b to tristate the PCLK3 / PCLK3
pins.
R/W
00b
Reference: Section 3.7.1 on page 52
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
77 of 102
Table 3-13: Configuration and Status Registers (Continued)
Register Name
Address
Bit
Description
R/W
Default
RSVD
2Fh - 30h
–
Reserved.
–
–
Audio_Control
(GS4901B only)
31h
15-10
Reserved. Set these bits to zero when writing to
31h.
–
–
31h
9-7
AFS_Reset_Window - These bits may be used to
adjust the value by which the audio clock counters
are allowed to drift from the output AFS pulse.
R/W
010b
The encoding scheme for this register is shown in
Table 3-9.
NOTE: The default setting of this register will
provide a reset window that is sufficient for most
standards. To maintain correct audio clock
frequencies for some VESA standards, the reset
window may have to be increased from its default
setting. In this case, set the value of this register to
1XX. See Table 3-9.
Reference: Section 3.7.2 on page 54
31h
6
Reserved. Set this it to zero when writing to 31h.
R/W
0
31h
5
Enable_384fs - set this bit HIGH to enable the 384fs
and 192fs audio clock outputs. This must be set in
addition to registers 3Fh to 41h.
R/W
0
NOTE: If this bit is HIGH, then a 512fs audio clock
will have a 33% duty cycle when fs = 96kHz.
Reference: Section 3.7.2 on page 54
31h
4-3
Reserved. Set these bits to zero when writing to
31h.
–
–
31h
2
Host_ASR_SEL - set this bit HIGH to select the audio
sample rate using register 32h instead of the
external ASR_SEL[2:0] pins.
R/W
0
R/W
0
R/W
0
The external ASR_SEL[2:0] pins will be ignored, but
should not be left floating.
Reference: Section 3.7.2 on page 54
31h
1
AFS_F_Pulse - set this bit to 1 to stretch the AFS
pulse duration from 1 line to 1 field.
Reference: Section 3.8.2 on page 59
31h
0
AFS_Reset_Disable - set this bit HIGH to disable the
10FID input reference pin from resetting the output
AFS pulse. If this bit is set HIGH, the output AFS
pulse will free-run or may be reset using register
1Ah. The external 10FID pin should not be left
floating.
Reference: Section 3.8.2 on page 59
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
78 of 102
Table 3-13: Configuration and Status Registers (Continued)
Register Name
Address
Bit
Description
R/W
Default
ASR_SEL[2:0]
(GS4901B only)
32h
15-3
Reserved. Set these bits to zero when writing to
32h.
–
–
32h
2-0
Replaces the external ASR_SEL[2:0] pins when
Host_ASR_Select (bit 2 of address 31h) is HIGH.
R/W
011b
The default setting of this register corresponds to
an audio sample rate of 48kHz.
Reference: Section 3.7.2 on page 54
RSVD
33h - 38h
–
Reserved.
–
–
Audio_Cap_Genlock
(GS4901B only)
39h
15-6
Reserved. Set these bits to zero when writing to
39h.
–
–
39h
5-0
Control signal to adjust loop bandwidth of audio
genlock block.
R/W
–
The value programmed in this register must be
between 10 and Audio_Res_Genlock - 21.
The default value of this register will depend on the
fundamental sampling frequency selected.
Reference: Section 3.6.2 on page 49
Audio_Res_Genlock
(GS4901B only)
3Ah
15-6
Reserved. Set these bits to zero when writing to
3Ah.
–
–
3Ah
5-0
Control signal to adjust loop bandwidth of audio
genlock block.
R/W
–
The value programmed in this register must be
between 32 and 42.
The default value of this register will depend on the
fundamental sampling frequency selected.
Reference: Section 3.6.2 on page 49
RSVD
3Bh-3Eh
–
Reserved
–
–
ACLK1_fs_Multiple
(GS4901B only)
3Fh
15-3
Reserved. Set these bits to zero when writing to
3Fh.
–
–
3Fh
2-0
The user may set this register to select the desired
frequency of the audio clock on ACLK1 (a multiple
of the fundamental sampling rate, fs). The audio
clock frequency may be set as: 512fs, 384fs, 256fs,
192fs, 128fs, 64fs, fs, or z-bit. See Table 3-8 for more
details.
R/W
0
NOTE: To output a frequency of 348fs or 192fs, bit 5
of register 31h must also be set HIGH.
Reference: Section 3.7.2 on page 54
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
79 of 102
Table 3-13: Configuration and Status Registers (Continued)
Register Name
Address
Bit
Description
R/W
Default
ACLK2_fs_Multiple
(GS4901B only)
40h
15-3
Reserved. Set these bits to zero when writing to
40h.
–
–
40h
2-0
The user may set this register to select the desired
frequency of the audio clock on ACLK2 (a multiple
of the fundamental sampling rate, fs). The audio
clock frequency may be set as: 512fs, 384fs, 256fs,
192fs, 128fs, 64fs, fs, or z-bit. See Table 3-8 for more
details.
R/W
0
NOTE: To output a frequency of 348fs or 192fs, bit 5
of register 31h must also be set HIGH.
Reference: Section 3.7.2 on page 54
ACLK3_fs_Multiple
(GS4901B only)
41h
15-3
Reserved. Set these bits to zero when writing to
41h.
–
–
41h
2-0
The user may set this register to select the desired
frequency of the audio clock on ACLK3 (a multiple
of the fundamental sampling rate, fs). The audio
clock frequency may be set as: 512fs, 384fs, 256fs,
192fs, 128fs, 64fs, fs, or z-bit. See Table 3-8 for more
details.
R/W
0
NOTE: To output a frequency of 348fs or 192fs, bit 5
of register 31h must also be set HIGH.
Reference: Section 3.7.2 on page 54
RSVD
42h
–
Reserved.
–
–
Output_Select_1
43h
15-5
Reserved. Set these bits to zero when writing to
43h.
–
–
43h
4
Current_1 - selects the current drive capability of
the TIMING_OUT_1 pin. Set this bit HIGH for high
current drive. Otherwise, the current drive will be
low.
R/W
0
R/W
0001b
Reference: Section 3.8.4 on page 62
43h
3-0
This register is used to select one of the 10
pre-programmed or 4 user programmed timing
signals available for output on the TIMING_OUT_1
pin. See Table 3-11 for more details.
Note: The default setting of this register is 0001b,
which corresponds to H Sync.
Reference: Section 3.8.4 on page 62
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
80 of 102
Table 3-13: Configuration and Status Registers (Continued)
Register Name
Address
Bit
Description
R/W
Default
Output_Select_2
44h
15-5
Reserved. Set these bits to zero when writing to
44h.
–
–
44h
4
Current_2 - selects the current drive capability of
the TIMING_OUT_2 pin. Set this bit HIGH for high
current drive. Otherwise, the current drive will be
low.
R/W
0
R/W
0010b
Reference: Section 3.8.4 on page 62
44h
3-0
This register is used to select one of the 10
pre-programmed or 4 user programmed timing
signals available for output on the TIMING_OUT_2
pin. See Table 3-11 for more details.
Note: The default setting of this register is 0010b,
which corresponds to H Blanking.
Reference: Section 3.8.4 on page 62
Output_Select_3
45h
15-5
Reserved. Set these bits to zero when writing to
45h.
–
–
45h
4
Current_3 - selects the current drive capability of
the TIMING_OUT_3 pin. Set this bit HIGH for high
current drive. Otherwise, the current drive will be
low.
R/W
0
R/W
0011b
Reference: Section 3.8.4 on page 62
45h
3-0
This register is used to select one of the 10
pre-programmed or 4 user programmed timing
signals available for output on the TIMING_OUT_3
pin. See Table 3-11 for more details.
Note: The default setting of this register is 0011b,
which corresponds to V Sync.
Reference: Section 3.8.4 on page 62
Output_Select_4
46h
15-5
Reserved. Set these bits to zero when writing to
46h.
–
–
46h
4
Current_4 - selects the current drive capability of
the TIMING_OUT_4 pin. Set this bit HIGH for high
current drive. Otherwise, the current drive will be
low.
R/W
0
R/W
0100b
Reference: Section 3.8.4 on page 62
46h
3-0
This register is used to select one of the 10
pre-programmed or 4 user programmed timing
signals available for output on the TIMING_OUT_4
pin. See Table 3-11 for more details.
Note: The default setting of this register is 0100b,
which corresponds to V Blanking.
Reference: Section 3.8.4 on page 62
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
81 of 102
Table 3-13: Configuration and Status Registers (Continued)
Register Name
Address
Bit
Description
R/W
Default
Output_Select_5
47h
15-5
Reserved. Set these bits to zero when writing to
47h.
–
–
47h
4
Current_5 - selects the current drive capability of
the TIMING_OUT_5 pin. Set this bit HIGH for high
current drive. Otherwise, the current drive will be
low.
R/W
0
R/W
0101b
Reference: Section 3.8.4 on page 62
47h
3-0
This register is used to select one of the 10
pre-programmed or 4 user programmed timing
signals available for output on the TIMING_OUT_5
pin. See Table 3-11 for more details.
Note: The default setting of this register is 0101b,
which corresponds to F Sync.
Reference: Section 3.8.4 on page 62
Output_Select_6
48h
15-5
Reserved. Set these bits to zero when writing to
48h.
–
–
48h
4
Current_6 - selects the current drive capability of
the TIMING_OUT_6 pin. Set this bit HIGH for high
current drive. Otherwise, the current drive will be
low.
R/W
0
R/W
0110b
Reference: Section 3.8.4 on page 62
48h
3-0
This register is used to select one of the 10
pre-programmed or 4 user programmed timing
signals available for output on the TIMING_OUT_6
pin. See Table 3-11 for more details.
Note: The default setting of this register is 0110b,
which corresponds to F Digital.
Reference: Section 3.8.4 on page 62
Output_Select_7
49h
15-5
Reserved. Set these bits to zero when writing to
49h.
–
–
49h
4
Current_7 - selects the current drive capability of
the TIMING_OUT_7 pin. Set this bit HIGH for high
current drive. Otherwise, the current drive will be
low.
R/W
0
R/W
0111b
Reference: Section 3.8.4 on page 62
49h
3-0
This register is used to select one of the 10
pre-programmed or 4 user programmed timing
signals available for output on the TIMING_OUT_7
pin. See Table 3-11 for more details.
Note: The default setting of this register is 0111b,
which corresponds to 10FID.
Reference: Section 3.8.4 on page 62
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
82 of 102
Table 3-13: Configuration and Status Registers (Continued)
Register Name
Address
Bit
Description
R/W
Default
Output_Select_8
4Ah
15-5
Reserved. Set these bits to zero when writing to
4Ah.
–
–
4Ah
4
Current_8 - selects the current drive capability of
the TIMING_OUT_8 pin. Set this bit HIGH for high
current drive. Otherwise, the current drive will be
low.
R/W
0
R/W
1000b
Reference: Section 3.8.4 on page 62
4Ah
3-0
This register is used to select one of the 10
pre-programmed or 4 user programmed timing
signals available for output on the TIMING_OUT_8
pin. See Table 3-11 for more details.
Note: The default setting of this register is 1000b,
which corresponds to Display Enable (DE).
Reference: Section 3.8.4 on page 62
RSVD
4Bh
–
Reserved.
–
–
Video_Control
4Ch
15-5
Reserved. Set these bits to zero when writing to
4Ch.
–
–
4Ch
4
10FID_F_pulse - set this bit HIGH to stretch the 10FID
pulse duration from 1 line to 1 field.
R/W
0
Reference: Section 3.8.1 on page 58
4Ch
3-2
Reserved. Set these bits to zero when writing to
4Ch.
–
–
4Ch
1
Host_VID_STD - set this bit HIGH to select the
output video standard using register 4Dh instead of
the external VID_STD[5:0] pins.
R/W
0
The external VID_STD[5:0] pins will be ignored, but
should not be left floating.
Reference: Section 1.4 on page 19
VID_STD[5:0]
4Ch
0
Reserved. Set this bit to zero when writing to 4Ch.
–
–
4Dh
15-6
Reserved. Set these bits to zero when writing to
4Dh.
–
–
4Dh
5-0
Replaces the external VID_STD[5:0] pins when
VID_From_Host (bit 1 of address 4Ch) is HIGH.
R/W
00h
Reference: Section 1.4 on page 19
RSVD
4Eh-55h
–
Reserved
–
–
Polarity
56h
15-10
Reserved. Set these bits to zero when writing to
56h.
–
–
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
83 of 102
Table 3-13: Configuration and Status Registers (Continued)
Register Name
Address
Bit
Description
R/W
Default
Polarity
56h
9
AFS (GS4901B only)- set this bit HIGH to invert the
polarity of the AFS timing output signal.
R/W
0
R/W
0
R/W
0
By default, the AFS signal is HIGH for the duration
of the first line of the n’th video frame to indicate
that the ACLK dividers have been reset at the start
of line 1 of that frame.
NOTE: The GS4900B does not generate an AFS pulse
and will ignore the setting of this bit.
Reference: Table 1-3
56h
8
10FID - set this bit HIGH to invert the polarity of the
10FID timing output signal.
By default, the 10FID signal will go HIGH for one
line at the start of the 10-field sequence.
Reference: Table 1-3
56h
7
DE - set this bit HIGH to invert the polarity of the DE
timing output signal.
By default, the DE signal will be HIGH whenever
pixel information is to be displayed on the display
device
Reference: Table 1-3
56h
6
Reserved. Set this bit to zero when writing to 56h.
–
–
56h
5
F_Digital - set this bit HIGH to invert the polarity of
the F Digital timing output signal.
R/W
0
R/W
0
R/W
0
R/W
0
By default, the F Digital signal will be HIGH for the
entire period of field 1.
Reference: Table 1-3
56h
4
F_Sync - set this bit HIGH to invert the polarity of
the F Sync timing output signal.
By default, the F Sync signal will be HIGH for the
entire period of field 1.
Reference: Table 1-3
56h
3
V_Blanking - set this bit HIGH to invert the polarity
of the V Blanking timing output signal.
By default, the V Blanking signal will be LOW for
the portion of the field/frame containing valid
video data.
Reference: Table 1-3
56h
2
V_Sync - set this bit HIGH to invert the polarity of
the V Sync timing output signal.
By default, the V Sync signal is active LOW.
Reference: Table 1-3
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
84 of 102
Table 3-13: Configuration and Status Registers (Continued)
Register Name
Address
Bit
Description
R/W
Default
Polarity
56h
1
H_Blanking - set this bit HIGH to invert the polarity
of the H Blanking timing output signal.
R/W
0
R/W
0
R/W
0
R/W
0
By default, the H Blanking signal will be LOW for
the portion of the video line containing valid video
samples.
Reference: Table 1-3
56h
0
H_Sync - set this bit HIGH to invert the polarity of
the H Sync timing output signal.
By default, the H Sync signal is active LOW.
Reference: Table 1-3
H_Start_1
57h
15-0
The value programmed in this register indicates the
pixel start point for the leading edge of the
user-programmed H Sync signal USER1_H.
NOTE: The value programmed in this register must
be less than the value programmed in H_Stop_1.
Reference: Section 3.8.3 on page 60
H_Stop_1
58h
15-0
The value programmed in this register indicates the
pixel end point for the trailing edge of the
user-programmed H Sync signal USER1_H.
NOTE: The value programmed in this register must
not exceed the maximum number of clock periods
per line of the outgoing standard.
Reference: Section 3.8.3 on page 60
V_Start_1
59h
15
Reserved. Set this bit to zero when writing to 59h.
–
–
59h
14-0
The value programmed in this register indicates the
start line number of the leading edge of the
user-programmed V Sync signal USER1_V. For
interlaced output standards, this value corresponds
to the odd field number.
R/W
0
NOTE: The value programmed in this register must
be less than the value programmed in V_Stop_1.
Reference: Section 3.8.3 on page 60
V_Stop_1
5Ah
15
Reserved. Set this bit to zero when writing to 5Ah.
–
–
5Ah
14-0
The value programmed in this register indicates the
end line number of the trailing edge of the
user-programmed V Sync signal USER1_V. For
interlaced output standards, this value corresponds
to the odd field number.
R/W
0
NOTE: The value programmed in this register must
not exceed the maximum number of lines per field
of the outgoing standard.
Reference: Section 3.8.3 on page 60
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
85 of 102
Table 3-13: Configuration and Status Registers (Continued)
Register Name
Address
Bit
Description
R/W
Default
Operator_Polarity_1
5Bh
15-4
Reserved. Set these bits to zero when writing to
5Bh.
–
–
5Bh
3
Polarity_1 - Use this bit to invert the polarity of the
final USER1 signal.
R/W
1
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
By default, the polarity of the user programmed
signals is active LOW. The polarity may be switched
to active HIGH by setting this bit LOW.
Reference: Section 3.8.3 on page 60
5Bh
2
AND_1 - logical operator: USER1_H AND USER1_V
Set this bit HIGH to output a signal that is only
active when both USER1_H and USER1_V are active.
When this bit is HIGH, bit 1 and bit 0 of this register
will be ignored.
Reference: Section 3.8.3 on page 60
5Bh
1
OR_1 - logical operator: USER1_H OR USER1_V
Set this bit HIGH to output a signal that is active
whenever USER1_H or USER1_V are active.
When this bit is HIGH bit 0 of this register will be
ignored.
Reference: Section 3.8.3 on page 60
5Bh
0
XOR_1 - logical operator: USER1_H XOR USER1_V
Set this bit HIGH to output a signal with the
following attributes: Signal becomes active when
either USER1_H or USER1_V is active. Signal is
inactive when USER1_H and USER1_V are both
active or both inactive.
Reference: Section 3.8.3 on page 60
H_Start_2
5Ch
15-0
The value programmed in this register indicates the
pixel start point for the leading edge of the
user-programmed H Sync signal USER2_H.
NOTE: The value programmed in this register must
be less than the value programmed in H_Stop_2
Reference: Section 3.8.3 on page 60
H_Stop_2
5Dh
15-0
The value programmed in this register indicates the
pixel end point for the trailing edge of the
user-programmed H Sync signal USER2_H.
NOTE: The value programmed in this register must
not exceed the maximum number of clock periods
per line of the outgoing standard.
Reference: Section 3.8.3 on page 60
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
86 of 102
Table 3-13: Configuration and Status Registers (Continued)
Register Name
Address
Bit
Description
R/W
Default
V_Start_2
5Eh
15
Reserved. Set this bit to zero when writing to 5Eh.
–
–
5Eh
14-0
The value programmed in this register indicates the
start line number of the leading edge of the
user-programmed V Sync signal USER2_V. For
interlaced output standards, this value corresponds
to the odd field line number.
R/W
0
NOTE: The value programmed in this register must
be less than the value programmed in V_Stop_2.
Reference: Section 3.8.3 on page 60
V_Stop_2
5Fh
15
Reserved. Set this bit to zero when writing to 5Fh.
–
–
5Fh
14-0
The value programmed in this register indicates the
end line number of the trailing edge of the
user-programmed V Sync signal USER2_V. For
interlaced output standards, this value corresponds
to the odd field line number.
R/W
0
NOTE: The value programmed in this register must
not exceed the maximum number of lines per field
of the outgoing standard.
Reference: Section 3.8.3 on page 60
Operator_Polarity_2
60h
15-4
Reserved. Set these bits to zero when writing to
60h.
–
–
60h
3
Polarity_2 - Use this bit to invert the polarity of the
final USER2 signal.
R/W
1
R/W
0
R/W
0
R/W
0
By default, the polarity of the user programmed
signals is active LOW. The polarity may be switched
to active HIGH by setting this bit LOW.
Reference: Section 3.8.3 on page 60
60h
2
AND_2 - logical operator: USER2_H AND USER2_V
Set this bit HIGH to output a signal that is only
active when both USER2_H and USER2_V are active.
When this bit is HIGH, bit 1 and bit 0 of this register
will be ignored.
Reference: Section 3.8.3 on page 60
60h
1
OR_2 - logical operator: USER2_H OR USER2_V
Set this bit HIGH to output a signal that is active
whenever USER2_H or USER2_V are active.
When this bit is HIGH bit 0 of this register will be
ignored.
Reference: Section 3.8.3 on page 60
60h
0
XOR_2 - logical operator: USER2_H XOR USER2_V
Set this bit HIGH to output a signal with the
following attributes: Signal becomes active when
either USER2_H or USER2_V is active. Signal is
inactive when USER2_H and USER2_V are both
active or both inactive.
Reference: Section 3.8.3 on page 60
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
87 of 102
Table 3-13: Configuration and Status Registers (Continued)
Register Name
Address
Bit
Description
R/W
Default
H_Start_3
61h
15-0
The value programmed in this register indicates the
pixel start point for the leading edge of the
user-programmed H Sync signal USER3_H.
R/W
0
R/W
0
NOTE: The value programmed in this register must
be less than the value programmed in H_Stop_3.
Reference: Section 3.8.3 on page 60
H_Stop_3
62h
15-0
The value programmed in this register indicates the
pixel end point for the trailing edge of the
user-programmed H Sync signal USER3_H.
NOTE: The value programmed in this register must
not exceed the maximum number of clock periods
per line of the outgoing standard.
Reference: Section 3.8.3 on page 60
V_Start_3
63h
15
Reserved. Set this bit to zero when writing to 63h.
–
–
63h
14-0
The value programmed in this register indicates the
start line number of the leading edge of the
user-programmed V Sync signal USER3_V. For
interlaced output standards, this value corresponds
to the odd field line number.
R/W
0
NOTE: The value programmed in this register must
be less than the value programmed in V_Stop_3.
Reference: Section 3.8.3 on page 60
V_Stop_3
64h
15
Reserved. Set this bit to zero when writing to 64h.
–
–
64h
14-0
The value programmed in this register indicates the
end line number of the trailing edge of the
user-programmed V Sync signal USER3_V. For
interlaced output standards, this value corresponds
to the odd field line number.
R/W
0
NOTE: The value programmed in this register must
not exceed the maximum number of lines per field
of the outgoing standard.
Reference: Section 3.8.3 on page 60
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
88 of 102
Table 3-13: Configuration and Status Registers (Continued)
Register Name
Address
Bit
Description
R/W
Default
Operator_Polarity_3
65h
15-4
Reserved. Set these bits to zero when writing to
65h.
–
–
65h
3
Polarity_3 - Use this bit to invert the polarity of the
final USER3 signal.
R/W
1
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
By default, the polarity of the user programmed
signals is active LOW. The polarity may be switched
to active HIGH by setting this bit LOW.
Reference: Section 3.8.3 on page 60
65h
2
AND_3 - logical operator: USER3_H AND USER3_V
Set this bit HIGH to output a signal that is only
active when both USER3_H and USER3_V are active.
When this bit is HIGH, bit 1 and bit 0 of this register
will be ignored.
Reference: Section 3.8.3 on page 60
65h
1
OR_3 - logical operator: USER3_H OR USER3_V
Set this bit HIGH to output a signal that is active
whenever USER3_H or USER3_V are active.
When this bit is HIGH bit 0 of this register will be
ignored.
Reference: Section 3.8.3 on page 60
65h
0
XOR_3 - logical operator: USER3_H XOR USER3_V
Set this bit HIGH to output a signal with the
following attributes: Signal becomes active when
either USER3_H or USER3_V is active. Signal is
inactive when USER3_H and USER3_V are both
active or both inactive.
Reference: Section 3.8.3 on page 60
H_Start_4
66h
15-0
The value programmed in this register indicates the
pixel start point for the leading edge of the
user-programmed H Sync signal USER4_H.
NOTE: The value programmed in this register must
be less than the value programmed in H_Stop_4.
Reference: Section 3.8.3
H_Stop_4
67h
15-0
The value programmed in this register indicates the
pixel end point for the trailing edge of the
user-programmed H Sync signal USER4_H.
NOTE: The value programmed in this register must
not exceed the maximum number of clock periods
per line of the outgoing standard.
Reference: Section 3.8.3 on page 60
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
89 of 102
Table 3-13: Configuration and Status Registers (Continued)
Register Name
Address
Bit
Description
R/W
Default
V_Start_4
68h
15
Reserved. Set this bit to zero when writing to 68h.
–
–
68h
14-0
The value programmed in this register indicates the
start line number of the leading edge of the
user-programmed V Sync signal USER4_V. For
interlaced output standards, this value corresponds
to the odd field line number.
R/W
0
NOTE: The value programmed in this register must
be less than the value programmed in V_Stop_4.
Reference: Section 3.8.3 on page 60
V_Stop_4
69h
15
Reserved. Set this bit to zero when writing to 69h.
–
–
69h
14-0
The value programmed in this register indicates the
end line number of the trailing edge of the
user-programmed V Sync signal USER4_V. For
interlaced output standards, this value corresponds
to the odd field line number.
R/W
0
NOTE: The value programmed in this register must
not exceed the maximum number of lines per field
of the outgoing standard.
Reference: Section 3.8.3 on page 60
Operator_Polarity_4
6Ah
15-4
Reserved. Set these bits to zero when writing to
6Ah.
–
–
6Ah
3
Polarity_4 - Use this bit to invert the polarity of the
final USER4 signal.
R/W
1
R/W
0
R/W
0
R/W
0
By default, the polarity of the user programmed
signals is active LOW. The polarity may be switched
to active HIGH by setting this bit LOW.
Reference: Section 3.8.3 on page 60
6Ah
2
AND_4 - logical operator: USER4_H AND USER4_V
Set this bit HIGH to output a signal that is only
active when both USER4_H and USER4_V are active.
When this bit is HIGH, bit 1 and bit 0 of this register
will be ignored.
Reference: Section 3.8.3 on page 60
6Ah
1
OR_4 - logical operator: USER4_H OR USER4_V
Set this bit HIGH to output a signal that is active
whenever USER4_H or USER4_V are active.
When this bit is HIGH bit 0 of this register will be
ignored.
Reference: Section 3.8.3 on page 60
6Ah
0
XOR_4 - logical operator: USER4_H XOR USER4_V
Set this bit HIGH to output a signal with the
following attributes: Signal becomes active when
either USER4_H or USER4_V is active. Signal is
inactive when USER4_H and USER4_V are both
active or both inactive.
Reference: Section 3.8.3 on page 60
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
90 of 102
Table 3-13: Configuration and Status Registers (Continued)
Register Name
Address
Bit
Description
R/W
Default
Ext_Audio_Mode
81h
15-0
Set this register to 20C1h to enable the Extended
Audio Mode of the device.
R/W
0
To fully enable this mode, VID_STD[5:0] must be set
to 4d, and the F_Lock_Mask and V_Lock_Mask bits
[4:3] of register address 16h must be set to 1.
NOTE: Once this register is programmed, it must be
updated using bit 6 of register 16h.
Reference: Section 3.9 on page 63
HD_Reference_Enable
82h
15-8
Reserved. Set these bits to zero when writing to
82h.
–
–
82h
7
HD_Ref_Enable - Set this bit HIGH to allow the
device to recognize the HD input reference formats
that have also been enabled in the
Reference_Standard_Disable register (address
11h-13h).
R/W
0
When this bit is set HIGH, the GS4901B/GS4900B will
only assert REF_LOST when the input signal is
removed.
Reference: Section 3.5 on page 43.
Ln_Count_Reset
82h
6-0
Reserved. Set these bits to zero when writing to
82h.
–
–
83h
15
Toggle this bit to reset the line-based counters in
the device.
R/W
0
–
–
This is only required when locking the 525-line SD
output standards to the “f/1.001” HD input
reference standards, AND:
1. The reference has been removed and subsequently
re-applied. In this case, the user should wait until the
reference has been re-detected by the device, which
may take up to 4 frames. See Section 3.5.3 on page
45.
OR
2. The device is locked to blanking signals from a
deserializer, and the SDI input to the deserializer has
been switched upstream from the system. See
Section 3.6.3 on page 52.
83h
14-0
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
Reserved. Set these bits to zero when writing to
83h.
91 of 102
3.11 JTAG
When the JTAG/HOST input pin of the GS4901B/GS4900B is set HIGH, the host interface
port will be configured for JTAG test operation. In this mode, pins 57 through 60 become
TCLK, TDI, TDO, and TMS. In addition, the RESET pin will operate as the test reset pin.
Boundary scan testing using the JTAG interface will be enabled in this mode.
There are two methods in which JTAG can be used on the GS4901B/GS4900B:
1. As a stand-alone JTAG interface to be used at in-circuit ATE (Automatic Test
Equipment) during PCB assembly; or
2. Under control of the host for applications such as system power on self tests.
When the JTAG tests are applied by ATE, care must be taken to disable any other devices
driving the digital I/O pins. If the tests are to be applied only at ATE, this can be
accomplished with high-impedance buffers used in conjunction with the JTAG/HOST
input signal. This is shown in Figure 3-16.
Application HOST
GS4911B/GS4910B
CS_TMS
SCLK_TCLK
SDIN_TDI
SDOUT_TDO
JTAG/HOST
In-circuit ATE probe
Figure 3-16: In-Circuit JTAG
Alternatively, if the test capabilities are to be used in the system, the host may still
control the JTAG/HOST input signal, but some means for tri-stating the host must exist
in order to use the interface at ATE. This is represented in Figure 3-17.
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
92 of 102
Application HOST
GS4911B/GS4910B
CS_TMS
SCLK_TCLK
SDIN_TDI
SDOUT_TDO
JTAG/HOST
Tri-State
In-circuit ATE probe
Figure 3-17: System JTAG
3.12 Device Power-Up
3.12.1 Power Supply Sequencing
The GS4901B/GS4900B has a recommended power supply sequence. To ensure correct
power-up, the ANALOG_VDD and CORE_VDD power pins should be powered before
IO_VDD.
Device pins may be driven prior to power-up without causing damage.
3.13 Device Reset
In order to initialize operating conditions to their default states, the application layer
must hold the RESET signal LOW during power up and for a minimum of 500us after the
last supply has reached its operating voltage.
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
93 of 102
4. Application Reference Design
4.1 GS4901B Typical Application Circuit
JTAG/HOSTb
SCLK
SDIN
SDOUT
CSb
VDD_IO
VDD_IO
10n
10n
1V8_VPLL
1V8_PCLK
10n
10n
GND_VPLL
22R
RESETb
PCLK1
22R
PCLK2
GENLOCKb
Controlled impedance
100-ohms differential
PCLK3
PCLK3b
GENLOCK
NC
IO_VDD
RESET
CS_TMS
SDOUT_TDO
SDIN_TDI
SCLK_TCLK
JTAG/HOST
PHS_GND
PHS_VDD
PCLK1&2_VDD
PCLK1&2_GND
PCLK1
IO_VDD
PCLK2
64
63
62
61
60
59
58
57
56
55
54
53
52
51
50
49
LOCK_LOST
REF_LOST
1V8_VPLL
10n
1V8_PCLK
VDD_IO
1V8_CORE
10n
GND_VPLL
38pF
1M
10n
24pF
0R
GND_XTAL
1V8_APLL
GND_XTAL
10n
LOCK_LOST
REF_LOST
VID_PLL_VDD
VID_PLL_GND
XTAL_VDD
X1
X2
XTAL_GND
CORE_GND
ANALOG_VDD
NC
ANALOG_GND
AUD_PLL_GND
AUD_PLL_VDD
10FID
HSYNC
GS4901B
GND_APLL
The 10FID input must be
grounded if it will not be used
65
LVDS/PCLK3_GND
PCLK3
PCLK3
LVDS/PCLK3_VDD
CORE_VDD
TIMING_OUT8
TIMING_OUT7
TIMING_OUT6
TIMING_OUT5
TIMING_OUT4
IO_VDD
TIMING_OUT3
TIMING_OUT2
TIMING_OUT1
ASR_SEL0
ASR_SEL1
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
10n
22R
22R
22R
22R
22R
22R
22R
22R
10n
TIMING8
TIMING7
TIMING6
TIMING5
TIMING4
TIMING3
TIMING2
TIMING1
VSYNC
IO_VDD
FSYNC
NC
VID_STD0
VID_STD1
VID_STD2
VID_STD3
VID_STD4
CORE_VDD
VID_STD5
ACLK1
ACLK2
ACLK3
IO_VDD
ASR_SEL2
VDD_XTAL
27MHz
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
GND_PAD
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
10FID
HSYNC
VSYNC
FSYNC
22R
22R
22R
VDD_IO
1V8_CORE
10n
ACLK1
ACLK2
ACLK3
10n
NOTE: The GS4911A inputs are 5V tolerant for
3V3 I/O operation only (IO_VDD=3V3)
10n
VID_STD0
VID_STD1
VID_STD2
VID_STD3
ASR_SEL0
ASR_SEL1
ASR_SEL2
NOTE: For a solution with the lowest output jitter, the GS9062 or GS9092A serializers are
recommended for use with the GS4901B/GS4900B.
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
94 of 102
4.2 GS4900B Typical Application Circuit
JTAG/HOSTb
SCLK
SDIN
SDOUT
CSb
VDD_IO
VDD_IO
10n
10n
1V8_PCLK
1V8_VPLL
10n
10n
22R
GND_VPLL
RESETb
PCLK1
22R
PCLK2
GENLOCKb
Controlled impedance
100-ohms differential
PCLK3
PCLK3b
GENLOCK
NC
IO_VDD
RESET
CS_TMS
SDOUT_TDO
SDIN_TDI
SCLK_TCLK
JTAG/HOST
PHS_GND
PHS_VDD
PCLK1&2_VDD
PCLK1&2_GND
PCLK1
IO_VDD
PCLK2
64
63
62
61
60
59
58
57
56
55
54
53
52
51
50
49
LOCK_LOST
REF_LOST
1V8_VPLL
10n
1V8_PCLK
1V8_CORE
VDD_IO
10n
VDD_XTAL
38pF
GND_VPLL
27MHz
10n
1M
24pF
0R
1V8_A
GND_XTAL
GND_XTAL
10n
LOCK_LOST
REF_LOST
VID_PLL_VDD
VID_PLL_GND
XTAL_VDD
X1
X2
XTAL_GND
CORE_GND
ANALOG_VDD
NC
ANALOG_GND
ANALOG_GND
ANALOG_GND
10FID
HSYNC
GND_A
The 10FID input must be
grounded if it will not be used
65
GND_PAD
LVDS/PCLK3_GND
PCLK3
PCLK3
LVDS/PCLK3_VDD
CORE_VDD
TIMING_OUT8
TIMING_OUT7
TIMING_OUT6
TIMING_OUT5
TIMING_OUT4
IO_VDD
TIMING_OUT3
TIMING_OUT2
TIMING_OUT1
ANALOG_GND
ANALOG_GND
GS4900B
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
VSYNC
IO_VDD
FSYNC
NC
VID_STD0
VID_STD1
VID_STD2
VID_STD3
VID_STD4
CORE_VDD
VID_STD5
NC
NC
NC
IO_VDD
ANALOG_GND
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
10n
22R
22R
22R
22R
22R
22R
22R
22R
10n
TIMING8
TIMING7
TIMING6
TIMING5
TIMING4
TIMING3
TIMING2
TIMING1
GND_A
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
10FID
HSYNC
VSYNC
FSYNC
VDD_IO
GND_A
1V8_CORE
NOTE: The GS4910A inputs are 5V tolerant for
3V3 I/O operation only (IO_VDD=3V3)
10n
10n
10n
VID_STD0
VID_STD1
VID_STD2
VID_STD3
NOTE: For a solution with the lowest output jitter, the GS9062 or GS9092A serializers are
recommended for use with the GS4901B/GS4900B.
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
95 of 102
5. References & Relevant Standards
Table 5-1: References & Relevant Standards
AES11-1997
Synchronization of Digital Audio Equipment in Studio Operations
SMPTE 125M-1995
Component Video Signal 4:2:2 – Bit-Parallel Digital Interface
SMPTE 170M-1999
Composite Analog Video Signal – NTSC for Studio Applications
SMPTE 244M-1995
System M/NTSC Composite Video Signals – Bit-Parallel Digital
Interface
SMPTE 260M-1999
1125/60 High-Definition Production System – Digital
Representation and Bit-Parallel Interface
SMPTE 267M-1995
Bit-Parallel Digital Interface – Component Video Signal 4:2:2 16x9
Aspect Ratio
SMPTE 274M-1998
1920 x 1080 Scanning and Analog and Parallel Digital Interfaces
for Multiple Picture Rates
SMPTE 293M-1996
720 x 483 Active Line at 59.94-Hz Progressive Scan Production –
Digital Representation
SMPTE 296M-1997
1280 x 720 Scanning, Analog and Digital Representation an
Analog Interface
SMPTE 318M-1999
Synchronization of 59.94- or 50-Hz Related Video and Audio
Systems in Analog and Digital Areas – Reference Signals
SMPTE 347M-2001
540 Mb/s Serial Digital Interface – Source Image Format Mapping
SMPTE RP 164-1996
Location of Vertical Interval Time Code
SMPTE RP 168-1993
Definition of Vertical Interval Switching Point for Synchronous
Video Switching
SMPTE RP 211-2000
Implementation of 24P, 25P and 30P Segmented Frames for 1920
x 1080 Production Format
ITU-R BT.601-5
Studio Encoding Parameters of Digital Television for Standard 4:3
and Wide-screen 16:9 Aspect Ratios
ITU-R BT.709-4
Parameter Values for the HDTV Standards for Production and
International Program Exchange ITU-R BT.799.3 Interface for
Digital Component Video Signals in 525-line and 625-line
Television Systems Operating at the 4:4:4 Level of
Recommendation ITU-R BT.601 (PART A)
ITU-R BT.1358
Studio Parameters of 625 and 525 Line Progressive Scan Television
Systems
VESA Monitor Timing
Specifications
VESA and industry Standards and Guidelines for Computer
Display Monitor Timing – Version 1.0, Revision 0.8 (Adoption
Date: September 17, 1998)
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
96 of 102
6. Package & Ordering Information
A
9.00
B
4.50
0.40+/-0.05
6.1 Package Dimensions
7.10+/-0.15
3.55
45°
45
9.00
PIN 1 AREA
7.10+/-0.15
4.50
°
3.55
CENTRE TAB
2X
2X
0.15 C
0.10 C
0.20 REF
0.15 C
0.25+/-0.05
0.50
C
64X
C A B
0.10
C
0.05
64X
0.90 +/- 0.10
+0.03
0.02-0.02
0.08 C
SEATING PLANE
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with GENLOCK
Data Sheet
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December 2009
ALL DIMENSIONS IN MM
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6.2 Recommended PCB Footprint
0.25
0.50
0.55
CENTER PAD
8.70
7.10
NOTE: All dimensions
are in millimeters.
7.10
8.70
The center pad of the PCB footprint should be connected to the ground plane by a minimum of
36 vias.
NOTE: Suggested dimensions only. Final dimensions should conform to customer design rules
and process optimizations.
6.3 Packaging Data
Parameter
Value
Package Type
9mm x 9mm 64-pin QFN
Moisture Sensitivity Level
3
Junction to Case Thermal Resistance, θj-c
9.3°C/W
Junction to Air Thermal Resistance, θj-a (at zero airflow)
24.6°C/W
Psi, ψ
0.2°C/W
Pb-free and RoHS Compliant
Yes
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6.4 Ordering Information
Part
Video
Clocks
Audio
Clocks
Max PCLK
Rate
GS4901B
√
√
54MHz
GS4900B
√
–
54MHz
Part Number
Package
Temperature Range
GS4901BCNE3
Pb-free 64-pin QFN
0°C to 70°C
GS4900BCNE3
Pb-free 64-pin QFN
0°C to 70°C
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7. Revision History
Version
ECR
PCN
Date
Changes and/or Modifications
A
138810
–
January 2006
New document.
0
140153
–
April 2006
Converting to Preliminary Data Sheet.
Corrected loop bandwidth
calculations. Updated description of
locking to HD formats. Updated
power consumption.
1
140830
40236
July 2006
Converting to Data Sheet. Modified
maximum system power values; added
maximum supply current information
in DC Electrical Characteristics.
2
141424
40495
August 2006
Updated terminal width to 0.25+/-0.05
on Package Dimensions and pin 1 ID
change to 45° chamfer.
3
148366
–
November 2007
Corrected H_Offset value in Section
3.2.1.13.2.1.1 Genlock Timing Offset.
Updated power values in Table 2-1:
DC Electrical Characteristics.
4
153276
–
December 2009
Updated document with new format.
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Data Sheet
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DOCUMENT IDENTIFICATION
CAUTION
DATA SHEET
ELECTROSTATIC SENSITIVE DEVICES
The product is in production. Gennum reserves the right to make changes to
the product at any time without notice to improve reliability, function or
design, in order to provide the best product possible.
DO NOT OPEN PACKAGES OR HANDLE EXCEPT AT A
STATIC-FREE WORKSTATION
GENNUM CORPORATE HEADQUARTERS
Phone: +1 (905) 632-2996
Fax: +1 (905) 632-2055
4281 Harvester Road, Burlington, Ontario L7L 5M4 Canada
E-mail: [email protected]
www.gennum.com
OTTAWA
SNOWBUSH IP - A DIVISION OF GENNUM
GERMANY
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Canada
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Phone: +1 (613) 270-0458
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Fax: +1 (416) 925-0581
E-mail: [email protected]
CALGARY
E-mail: [email protected]
3553 - 31st St. N.W., Suite 210
Calgary, Alberta T2L 2K7
Canada
Web Site: http://www.snowbush.com
Phone: +1 (403) 284-2672
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North Building, Walden Court
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Phone: +1 (416) 848-0328
E-mail: [email protected]
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NORTH AMERICA EASTERN REGION
Fax: +44 1279 714171
Shinjuku Green Tower Building 27F
6-14-1, Nishi Shinjuku
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#208(A), Nirmala Plaza,
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Phone: +91 (674) 653-4815
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Fax: +91 (674) 259-5733
6F-4, No.51, Sec.2, Keelung Rd.
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8F Jinnex Lakeview Bldg.
65-2, Bangidong, Songpagu
Seoul, Korea 138-828
Phone: +44 1279 714170
E-mail: [email protected]
Phone: (886) 2-8732-8879
Fax: (886) 2-8732-8870
4281 Harvester Road
Burlington, Ontario L7L 5M4
Canada
Phone: +1 (905) 632-2996
Fax: +1 (905) 632-2055
E-mail: [email protected]
Phone: +82-2-414-2991
Fax: +82-2-414-2998
E-mail: [email protected]
E-mail: [email protected]
Gennum Corporation assumes no liability for any errors or omissions in this document, or for the use of the circuits or devices described herein. The sale of
the circuit or device described herein does not imply any patent license, and Gennum makes no representation that the circuit or device is free from patent
infringement.
All other trademarks mentioned are the properties of their respective owners.
GENNUM and the Gennum logo are registered trademarks of Gennum Corporation.
© Copyright 2006 Gennum Corporation. All rights reserved.
www.gennum.com
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with GENLOCK
Data Sheet
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December 2009
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