TI TLC34076

TLC34076, TLC34076M
Data Manual
Video Interface Palette
SLAS054A
October 1997
Printed on Recycled Paper
IMPORTANT NOTICE
Texas Instruments (TI) reserves the right to make changes to its products or to discontinue any
semiconductor product or service without notice, and advises its customers to obtain the latest
version of relevant information to verify, before placing orders, that the information being relied
on is current.
TI warrants performance of its semiconductor products and related software to the specifications
applicable at the time of sale in accordance with TI’s standard warranty. Testing and other quality
control techniques are utilized to the extent TI deems necessary to support this warranty.
Specific testing of all parameters of each device is not necessarily performed, except those
mandated by government requirements.
Certain applications using semiconductor products may involve potential risks of death,
personal injury, or severe property or environmental damage (“Critical Applications”).
TI SEMICONDUCTOR PRODUCTS ARE NOT DESIGNED, INTENDED, AUTHORIZED, OR
WARRANTED TO BE SUITABLE FOR USE IN LIFE-SUPPORT APPLICATIONS, DEVICES
OR SYSTEMS OR OTHER CRITICAL APPLICATIONS.
Inclusion of TI products in such applications is understood to be fully at the risk of the customer.
Use of TI products in such applications requires the written approval of an appropriate TI officer.
Questions concerning potential risk applications should be directed to TI through a local SC
sales office.
In order to minimize risks associated with the customer’s applications, adequate design and
operating safeguards should be provided by the customer to minimize inherent or procedural
hazards.
TI assumes no liability for applications assistance, customer product design, software
performance, or infringement of patents or services described herein. Nor does TI warrant or
represent that any license, either express or implied, is granted under any patent right, copyright,
mask work right, or other intellectual property right of TI covering or relating to any combination,
machine, or process in which such semiconductor products or services might be or are used.
Copyright  1997, Texas Instruments Incorporated
Contents
Section
Title
Page
1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2 Functional Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3 Terminal Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.4 Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.5 Terminal Functions (TLC34076C and TLC34076M) . . . . . . . . . . . . . . . . . . . . . . . . .
1–1
1–1
1–3
1–4
1–7
1–8
2
Detailed Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–1
2.1 Microprocessor Unit (MPU) Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–1
2.2 Color Palette RAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–1
2.2.1 Writing to the Color Palette RAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–2
2.2.2 Reading From the Color Palette RAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–2
2.2.3 Palette Page Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–2
2.3 Input/Output Clock Selection and Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–2
2.3.1 SCLK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–5
2.3.2 VCLK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–6
2.4 Multiplexing Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–8
2.4.1 VGA Pass-Through Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–11
2.4.2 Multiplexing Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–12
2.4.3 Special Nibble Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–12
2.4.4 True-Color Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–12
2.4.5 Multiplex Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–15
2.4.6 Read Masking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–16
2.5 Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–16
2.5.1 Power-On Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–16
2.5.2 Hardware Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–16
2.5.3 Software Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–16
2.5.4 VGA Pass-Through Mode Default Conditions . . . . . . . . . . . . . . . . . . . . . . . 2–17
2.6 Analog Output Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–17
2.7 Frame-Buffer Interface with Little-Endian and Big-Endian Modes . . . . . . . . . . . . 2–19
2.8 HSYNC, VSYNC, and BLANK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–19
2.9 Split Shift Register Transfer VRAMs and Special Nibble Mode . . . . . . . . . . . . . . 2–20
2.9.1 Split Shift Register Transfer VRAMs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–20
2.9.2 Special Nibble Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–21
2.10 MUXOUT Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–23
2.11 General Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–23
2.11.1 HSYNCOUT and VSYNCOUT (Bits 0 and 1) . . . . . . . . . . . . . . . . . . . . . . . 2–23
2.11.2 Split Shift Register Transfer Enable (SSRT) and
Special Nibble Mode Enable (SNM) (Bits 2 and 3) . . . . . . . . . . . . . . . . . . . 2–23
2.11.3 Pedestal Enable Control (Bit 4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–23
2.11.4 Sync Enable Control (Bit 5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–24
iii
2.11.5 Little-Endian and Big-Endian Mode Control (Bit 6) . . . . . . . . . . . . . . . . . .
2.11.6 MUXOUT (Bit 7) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.12 Test Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.12.1 Frame-Buffer Data Flow Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.12. Identification (ID) Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.12.3 Ones-Accumulation Screen Integrity Test . . . . . . . . . . . . . . . . . . . . . . . . . .
2.12.4 Analog Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
2–24
2–24
2–24
2–25
2–25
2–25
2–26
Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–1
3.1 Absolute Maximum Ratings Over Operating Free-Air Temperature Range
(Unless Otherwise Noted)† . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–1
3.2 Recommended Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–1
3.3 Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–2
3.3.1 Electrical Characteristics for TLC34076C Over Operating Free-Air
Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–2
3.3.2 Electrical Characteristics for TLC34076M Over Operating Free-Air
Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–3
3.4 Operating Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–4
3.4.1 Operating Characteristics for TLC34076C Over Recommended
Ranges of Supply Voltage and Operating Free-Air Temperature . . . . . . . 3–4
3.4.2 Operating Characteristics for TLC34076M Over Recommended
Ranges of Supply Voltage and Operating Free-Air Temperature . . . . . . . . 3–5
3.5 Timing Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–6
3.5.1 Timing Requirements for TLC34076C Over Recommended Ranges
of Supply Voltages and Operating Temperature . . . . . . . . . . . . . . . . . . . . . 3–6
3.5.2 Timing Requirements for TLC34076M Over Recommended Ranges
of Supply Voltages and Operating Temperature . . . . . . . . . . . . . . . . . . . . . 3–8
3.6 Switching Characteristics for TLC34076C and TLC34076M Over
Recommended Ranges of Supply Voltages and Operating Temperature . . . . . . 3–9
3.7 Timing Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–12
Appendix A SCLK/VCLK and the TMS340x0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A–1
Appendix B Printed Circuit Board Layout Considerations . . . . . . . . . . . . . . . . . . . . . . . B–1
Appendix C SCLK Frequency < VCLK Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C–1
Appendix D Mechanical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D–1
iv
List of Illustrations
Figure
Title
Page
2–1 DOTCLK/VCLK/SCLK Relationship . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–4
2–2 SCLK/VCLK Control Timing (SSRT Disabled, SCLK Frequency = VCLK
Frequency) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–6
2–3 SCLK/VCLK Control Timing (SSRT Enabled, SCLK Frequency = VCLK
Frequency) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–7
2–4 SCLK/VCLK Control Timing (SSRT Disabled, SCLK Frequency = 4 y VCLK
Frequency) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–7
2–5 SCLK/VCLK Control Timing (SSRT Enabled, SCLK Frequency = 4 y VCLK
Frequency) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–8
2–6 Equivalent Circuit of the IOG Current Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–17
2–7 7.5-IRE, 8-Bit Composite Video Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–18
2–8 0-IRE, 8-Bit Composite Video Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–18
2–9 Relationship Between SFLAG/NFLAG, BLANK, and SCLK . . . . . . . . . . . . . . . . . . . . . 2–20
2–10 SFLAG/NFLAG Timing in Special Nibble Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–22
2–11 Test-Register Control-Word State Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–25
2–12 Internal Comparator Circuitry for Analog Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–27
3–1 MPU Interface Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–12
3–2 Video Input/Output Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–13
3–3 SFLAG/NFLAG Timing (When SSRT Function is Enabled) . . . . . . . . . . . . . . . . . . . . . 3–13
v
List of Tables
Table
2–1
2–2
2–3
2–4
2–5
Title
Page
Internal Register Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–1
Allocation of Palette Page Register Bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–2
Input Clock Selection Register Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–3
Output Clock Selection Register Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–3
VCLK/SCLK Divide Ratio Selection
(Output Clock Selection Register Value in Hex) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–4
2–6 Mode and Bus Width Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–9
2–7 True-Color Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–13
2–8 True-Color Bit Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–14
2–9 VGA Pass-Through Mode Default Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–17
2–10 Pixel Data Distribution in Special Nibble Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–21
2–11 General Control Register Bit Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–23
2–12 Test Mode Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–24
2–13 Test Register Bit Definitions for Analog Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–26
2–14 Bit Coding for Analog Comparisons of Bits D7 – D4 . . . . . . . . . . . . . . . . . . . . . . . . . . 2–26
vi
1 Introduction
The TLC34076C and TLC34076M are commercial and military versions, respectively, of a Texas
Instruments video interface palette (VIP) designed for lower system cost with a higher level of integration.
Lower system cost and higher integration are achieved by incorporating all the high-speed timing,
synchronizing, and multiplexing logic usually associated with graphics systems into one device, thus greatly
reducing chip count. Since all high-speed signals (excluding the clock source) are contained on-chip, RF
noise considerations are simplified. Maximum flexibility is provided through the pixel multiplexing scheme,
which allows for 32-, 16-, 8-, and 4-bit pixel buses to be accommodated without any circuit modification. This
enables the system to be easily reconfigured for varying amounts of available video RAM (VRAM). Data can
be split into 1, 2, 4, or 8 bit-planes. The TLC34076 is software-compatible with the IMSG176/8 and
Brooktree BT476/8 color palettes.
The TLC34076 VIP is pin-for-pin compatible with the TLC34075 VIP, but contains additional 24- and 16-bit
true-color modes, as well as the ability to select little-endian or big-endian data formats for the pixel bus
frame buffer interface.
The TLC34076 features a separate VGA bus that allows data from the feature connector of most
VGA-supported personal computers to be fed directly into the palette without the need for external data
multiplexing. This allows a replacement graphics board to remain downward compatible by utilizing the
existing graphics circuitry often located on the motherboard.
The 24- and 16-bit true-color modes that are provided allow bits of color information to be transferred directly
from the pixel port to the digital-to-analog converters (DACs). Depending on which true-color mode is
selected, an overlay function is provided using the remaining bits of the pixel bus. The 24-bit modes allow
overlay with the eight remaining bits of the pixel bus, while the TARGA (5-5-5) 16-bit mode allows overlay
with the one remaining bit of the divided pixel bus.
The TLC34076 has a 256-by-24 color lookup table with triple 8-bit video D/A converters capable of directly
driving a doubly terminated 75-Ω line. Sync generation is incorporated on the green output channel. HSYNC
and VSYNC are fed through the device and optionally inverted to indicate screen resolution to the monitor.
A palette page register provides the additional bits of palette address when 1, 2, or 4 bit-planes are used.
This allows the screen colors to be changed with only one MPU write cycle.
Clocking is provided through one of four or five inputs (three TTL compatible and either one ECL compatible
or two TTL compatible) and is software selectable. The video and shift clock outputs provide a
software-selected divide ratio of the chosen clock input.
The TLC34076 can be connected directly to the serial port of VRAM devices, eliminating the need for any
discrete logic. Support for split shift register transfers is also provided.
1.1
Features
•
•
•
•
•
•
•
•
•
Versatile Multiplexing Interface to Allow Lower Pixel Bus Rate
High Level of Integration to Provide Lower System Cost and Complexity
Direct VGA Pass-Through Capability
Versatile Pixel Bus Interface to Support Little-Endian and Big-Endian Data Formats
True-Color (direct-addressing) Mode to Support Various 24-Bit and 16-Bit Formats
Compatible with 5-6-5 XGA Format
Compatible with 5-5-5 TARGA Format
Interfaces Directly to TMS34010/TMS34020 and Other Graphics Processors
Triple 8-bit D/A Converters
Brooktree is a trademark of the Brooktree Corporation.
TARGA is a registered trademark of Truevision Incorporated.
1–1
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Available in 85-, 110-,135-, and 170-MHz Versions
256-Word Color Palette RAM
Palette Page Register
On-Chip Voltage Reference
RS-343A-Compatible Outputs
TTL-Compatible Inputs
Standard MPU Interface
Pixel Word Mask
On-Chip Clock Selection
Interfaces Directly to Video RAM
Supports Split Shift Register Transfers
Software Downward-Compatible with INMOS IMSG176/8 and Brooktree BT476/8 Color
Palettes
TIGA-Software-Standard Compatible
LinEPIC 1-µm CMOS Process
LinEPIC and TIGA are trademarks of Texas Instruments Incorporated.
INMOS is a trademark of INMOS International Limited.
1–2
1.2
24
24
16
8
16
15
True-Color
Pipeline Delay
COMP
8
32
8
1
4
32
P0 – P31
32
Input
Latch
VGA0 – VGA7
8
32
8
2
32
7
8
D0 – D7
4
RS0 – RS3
RD
WR
Page
Register
1
32
8
8
Color
Palette
RAM
8
8
Output
MUX
8
8
8
DAC
IOR
DAC
IOG
DAC
IOB
8 8 8
Test
Register
6
MPU
Registers
& Control
Read
Mask
24
Video MUX
& Control
8
HSYNCOUT
VSYNCOUT
MUXOUT
Clock
Control
Functional Block Diagram
V REF
FS ADJUST
32
32
VGABLANK
BLANK
VSYNC
HSYNC
8/6
VCLK
SCLK
CLK3
CLK0 – CLK3
SFLAG/
NFLAG
1–3
1.3
Terminal Assignments
The terminal assignments for TLC34076C are shown in the 84-pin FN package; terminal assignments for
TLC34076M are shown in the 84-pin GA package.
11 10 9
P17
P16
P15
P14
P13
P12
P11
P10
P9
P8
P7
P6
P5
P4
P3
P2
P1
P0
WR
RD
RS0
8
7 6 5 4
3
2
VCLK
CLK0
CLK1
CLK2
P18
P19
P20
P21
P22
P23
P24
P25
P26
P27
P28
P29
P30
P31
VDD
GND
SCLK
84-PIN FN PACKAGE (TOP VIEW)
1 84 83 82 81 80 79 78 77 76 75
12
74
13
73
14
72
15
71
16
70
17
69
18
68
19
67
20
66
21
65
22
64
23
63
24
62
25
61
26
60
27
59
28
58
29
57
30
56
31
55
32
54
1–4
HSYNCOUT
VSYNCOUT
IOR
IOG
IOB
FS ADJUST
COMP
VREF
RS1
RS2
RS3
D0
D1
D2
D3
D4
D5
D6
D7
GND
VDD
33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53
CLK3
CLK3
VGA7
VGA6
VGA5
VGA4
VGA3
VGA2
VGA1
VGA0
8/6
MUXOUT
SFLAG/NFLAG
VGABLANK
BLANK
VSYNC
HSYNC
VDD
GND
VDD
GND
1.3
Terminal Assignments (Continued)
84ĆPIN GA PACKAGE (TOP VIEW)
12
RS0
D0
D1
D3
D5
D7
VDD
11
WR
RS2
RS3
D2
D4
D6
GND
10
P0
RD
RS1
9
P2
P1
8
P4
P3
7
P6
6
HSYNCĆ
OUT
VSYNCĆ
OUT
FS
IOR
IOB
IOG
COMP
VDD
DVDD
GND
GND
HSYNC
VSYNC
BLANK
ADJUST
VREF
VGAĆ
SFLAG/
BLANK
NFLAG
P5
8/6
MUXOUT
P8
P7
VGA1
VGA0
5
P9
P10
VGA3
VGA2
4
P11
P12
VGA5
VGA4
CLK2
CLK3
VGA6
(ESD symbol or alignment
dot on top)
3
P13
P15
P17
2
P14
P16
P19
P22
P24
P27
P29
P31
GND
CLK0
CLK1
VGA7
1
P18
P20
P21
P23
P25
P26
P28
P30
VDD
SCLK
VCLK
CLK3
C
D
E
A
B
F
G
H
J
K
L
M
1–5
1.3
Terminal Assignments (Continued)
84ĆPIN GA PACKAGE (BOTTOM VIEW)
FS
12
Vref
ADJUST
11
DVDD
10
9
IOB
IOR
VDD
COMP
IOG
HSYNC
GND
GND
BLANK
VSYNC
HSYNCĆ
OUT
VSYNCĆ
OUT
VDD
D7
D5
D3
D1
D0
RS0
GND
D6
D4
D2
RS3
RS2
WR
RS1
RD
P0
P1
P2
P3
P4
SFLAG/
VGAĆ
NFLAG
BLANK
7
MUXOUT
8/6
P5
P6
6
VGA0
VGA1
P7
P8
5
VGA2
VGA3
P10
P9
4
VGA4
VGA5
P12
P11
P17
P15
P13
8
(ESD symbol or alignment
dot on top)
3
VGA6
CLK3
CLK2
2
VGA7
CLK1
CLK0
GND
P31
P29
P27
P24
P22
P19
P16
P14
1
CLK3
VCLK
SCLK
VDD
P30
P28
P26
P25
P23
P21
P20
P18
H
G
F
E
D
C
M
1–6
L
K
J
B
A
1.4
Ordering Information
TLC34076 – (X)XX
M
PP
Pixel clock frequency indicator
Must contain two or three characters:
– 85:
85-MHz pixel clock
– 110: 110-MHz pixel clock
– 135: 135-MHz pixel clock
– 170: 170-MHz pixel clock
Military extension
Package
Must contain two letters:
FN: plastic, square, leaded chip carrier (formed leads)
GA: 84-pin (12 x 12) ceramic pin-grid array
1–7
1.5
Terminal Functions (TLC34076C and TLC34076M)
TERMINAL
NAME
I/O
NO.{
NO.}
DESCRIPTION
I/O
DESCRIPTION
BLANK,
VGABLANK
60, 61
M9, L8
I
Blanking inputs. Two blanking inputs are provided in order to remove
any external multiplexing of the signals that may cause data and
Blank to skew. When the VGA pass-through mode is set in the
multiplex control register, the VGABLANK input is used for blanking;
otherwise, BLANK is used.
CLK0 – CLK2
77, 76,
75
K2, L2, K3
I
Dot clock inputs. Any of the three clocks can drive the dot clock at
frequencies up to 135 MHz. When VGA pass-through mode is
active, CLK0 is used by default.
CLK3, CLK3
74, 73
M1, L3
I
Dual-mode dot clock input. The clock input is an ECL-compatible
input, but a TTL clock may be used on either CLK3 or CLK3 when
so selected in the input clock selection register. This input may be
selected as the dot clock for any frequency of operation up to the
device limit. It can also be used with a single-ended ECL clock
source when the unused input is externally terminated to provide the
proper common mode level.
COMP
52
K11
I
Compensation input. COMP provides compensation for the internal
reference amplifier. A resistor (optional) and ceramic capacitor are
required between COMP and VDD. The resistor and capacitor must
be as close to the device as possible to avoid noise pickup (see
Appendix B for more details).
D0 – D7
36 – 43
B12, C12,
D11, D12,
E11, E12,
F11, F12
I/O
MPU interface data bus. D0 – D7 transfers data in and out of the
register map and palette/overlay RAM.
FS ADJUST
51
L12
I
Full-scale adjustment. A resistor connected between FS ADJUST
and ground controls the full-scale range of the DACs.
GND
44, 54,
56, 80
J2, L10,
K10, G11
HSYNCOUT,
VSYNCOUT
46, 47
H12, H11
O
Horizontal and vertical sync outputs. The HSYNCOUT and
VSYNCOUT are the true/complement gate mentioned in the
HSYNC and VSYNC description below (see Section 2.8).
HSYNC,
VSYNC
58, 59
M10, L9
I
Horizontal and vertical sync inputs. HSYNC and VSYNC generate
the sync level on the green current output. They are active-low inputs
for the normal modes and are passed through a true/complement
gate. For the VGA pass-through mode, they are passed through to
HSYNCOUT and VSYNCOUT without polarity change as specified
by the control register (see Section 2.8).
IOR, IOG, IOB
48, 49,
50
J12, J11,
K12
O
Analog current outputs. The IOR, IOG, and IOB outputs can drive a
37.5-Ω load directly (doubly terminated 75-Ω line), thus eliminating
the need for any external buffering.
Ground. All GND terminals must be connected together. The analog
and digital GND terminals are connected internally.
{ Terminal numbers shown are for the FN package.
} Terminal numbers shown are for the GA package.
NOTES: 1. Although leaving unused terminals floating does not adversely affect device operation, tying unused
terminals to ground lowers power consumption, thus is recommended.
2. All digital inputs and outputs are TTL compatible, unless otherwise noted.
1–8
1.5
Terminal Functions (TLC34076C and TLC34076M) (Continued)
TERMINAL
NAME
NO.{
NO.}
I/O
DESCRIPTION
MUXOUT
63
M7
O
MUX output control. MUXOUT is software programmable. It is set
low to indicate to external devices that VGA pass-through mode is
being used when the multiplex control register value is set to 2Dh.
When bit 7 of the general-control register is set high after the mode
is set, this output goes high. This terminal is only used for external
control; it affects no internal circuitry.
P0 – P31
29 –1,
84 – 82
A10, B9, A9,
B8, A8, B7,
A7, B6, A6,
A5, B5, A4,
B4, A3, A2,
B3, B2, C3,
A1, C2, B1,
C1, D2, D1,
E2, E1, F1,
F2, G1, G2,
H1, H2
I
Pixel input port. This port can be used in various modes as shown
in the MUX control register. It is recommended that unused terminals
be tied to ground. It also supports little-endian and big-endian data
formats. All the unused terminals must be tied to GND.
RD
31
B10
I
Read strobe input. A low on RD initiates a read from the TLC34076
register map. Reads are performed asynchronously and are initiated
on the falling edge of RD (see Figure 3 –1).
RS0 – RS3
32–35
A12, C10,
B11, C11
I
Register select inputs. RSx specifies the location in the register map
that is to be accessed (see Table 2–1).
SCLK
79
K1
O
Shift clock output. SCLK is selected as a submultiple of the dot clock
input. SCLK is gated off during blanking.
SFLAG/
NFLAG
62
M8
I
Split shift register transfer flag or nibble flag input. SFLAG/NFLAG
has two functions. When the general control register bit 3 = 0 and bit
2 = 1, the split shift register transfer function is enabled and a
low-to-high transition on SFLAG/NFLAG during a blank sequence
initiates an extra SCLK cycle to allow a split shift register transfer in
the VRAMs. When the general control register bit 3 = 1 and bit 2 = 0,
special nibble mode is enabled and this input is sampled at the falling
edge of VCLK. A high value sampled indicates that the next SCLK
rising edge should latch the high nibble of each byte of the pixel data
bus; a low value sampled indicates that the low nibble of each byte
of the pixel data bus should be latched (see Section 2.9). When the
general control register bit 3 = 0 and bit 2 = 0, the condition of
SFLAG/NFLAG is ignored. The condition of bit 3 = 1, bit 2 = 1 is not
allowed, and device operation is unpredictable when they are so set.
VCLK
78
L1
O
Video clock output. VCLK is user-programmable output for
synchronization of the TLC34076 to a graphics processor.
VDD
45, 55,
57, 81
J1, L11, G12
Power. All VDD terminals must be connected. The analog and digital
VDD terminals are connected internally.
{ Terminal numbers shown are for the FN package.
} Terminal numbers shown are for the GA package.
NOTES: 1. Although leaving unused terminals floating does not adversely affect device operation, tying unused
terminals to ground lowers power consumption, thus is recommended.
2. All digital inputs and outputs are TTL compatible, unless otherwise noted.
1–9
1.5
Terminal Functions (TLC34076C and TLC34076M) (Continued)
TERMINAL
NAME
NO.{
NO.}
I/O
DESCRIPTION
VGA0 – VGA7
65 – 72
M6, L6, M5,
L5, M4, L4,
M3, M2
I
VGA pass-through bus. The VGAn bus can be selected as the pixel
bus for the VGA pass-through mode. It does not allow for any
multiplexing.
VREF
53
M12
WR
30
A11
I
Write strobe input. A low on WR initiates a write to the TLC34076
register map. Write transfers are asynchronous. The data written to
the register map is latched on the rising edge of WR (see
Figure 3–1).
8/6
64
L7
I
DAC resolution selection. The 8/6 terminal selects the data bus
width (8 or 6 bits) for the DACs and is provided to maintain
compatibility with the INMOS IMSG176/8 color palette. When this
terminal is high, 8-bit bus transfers are used, with D7 being the MSB
and D0 the LSB. For 6-bit bus operation, while the color palette still
has the 8-bit information, D5 shifts to the bit 7 position, D0 shifts to
the bit 2 position, and the two LSBs are filled with zeros at the output
MUX to the DAC. When read in the 6-bit mode, the palette holding
register zeros the two MSBs.
Voltage reference for DACs. An internal voltage reference of
nominally 1.235 V is supplied. A 0.1-µF ceramic capacitor between
VREF and GND is recommended for noise filtering using either the
internal or an external reference voltage. The internal reference
voltage can be overridden by an externally supplied voltage. The
typical connection is shown in Appendix B.
{ Terminal numbers shown are for the FN package.
} Terminal numbers shown are for the GA package.
NOTES: 1. Although leaving unused terminals floating does not adversely affect device operation, tying unused
terminals to ground lowers power consumption, thus is recommended.
2. All digital inputs and outputs are TTL compatible, unless otherwise noted.
1–10
2 Detailed Description
2.1
Microprocessor Unit (MPU) Interface
The processor interface is controlled using read and write strobes (RD, WR), four register select terminals
(RS0 – RS3), and the 8/6 select terminal. The select 8/6 terminal selects between 8-bit and 6-bit operation
and is provided in order to maintain compatibility with the IMSG176/8 color palette. This operation is carried
out to utilize the maximum range of the DACs.
The internal register map is shown in Table 2–1. The MPU interface operates asynchronously, with data
transfers being synchronized by internal logic. All the register locations support read and write operations.
Table 2–1. Internal Register Map
2.2
RS3
RS2
RS1
RS0
REGISTER ADDRESSED BY MPU
L
L
L
L
Palette address register – write mode
L
L
L
H
Color palette holding register
L
L
H
L
Pixel read mask
L
L
H
H
Palette address register – read mode
L
H
L
L
Reserved
L
H
L
H
Reserved
L
H
H
L
Reserved
L
H
H
H
Reserved
H
L
L
L
General control register
H
L
L
H
Input clock selection register
H
L
H
L
Output clock selection register
H
L
H
H
Multiplex control register
H
H
L
L
Palette page register
H
H
L
H
Reserved
H
H
H
L
Test register
H
H
H
H
Reset state
Color Palette RAM
The color palette RAM is addressed by two internal 8-bit registers, one for reading from the RAM and one
for writing to the RAM. These registers are automatically incremented following a RAM transfer, allowing
the entire palette to be read/written with only one access of the address register. When the address register
increments beyond the last location in RAM, it is reset to the first location (address 0). Although all read and
write accesses to the RAM are asynchronous to SCLK, VCLK, and the dot clock, they are performed within
one dot clock and so do not cause any noticeable disturbance on the display.
The color palette RAM is 24 bits wide for each location (8 bits each for red, green, and blue). When 6-bit
mode is chosen (8/6 = low), the two MSBs are still written to the color palette RAM. However, when they
are read back in the 6-bit mode, the two MSBs are set to 0 to maintain compatibility with the IMSG176/8 and
BT476/8 color palettes. The output MUX shifts the six LSBs to the six MSB positions, fills the two LSBs with
0s, then feeds the 8 bits to the DAC. With the 8/6 terminal held low, data on the lowest 6 bits of the data bus
are internally shifted up by two bits to occupy the upper six bits at the output MUX, and the bottom two bits
are then cleared to 0. The test register and the ones-accumulation register both take data before the output
MUX to give the user the maximum flexibility.
The color-palette RAM-access methodology is described in the following two sections and is fully
compatible with the INMOS IMSG176/8 and Brooktree Bt476/8 color palettes.
2–1
2.2.1
Writing to the Color Palette RAM
To load the color palette RAM, the MPU must first write to the address register (write mode) with the address
where the modification is to start. This action is followed by three successive writes to the palette-holding
register with eight bits each of red, green, and blue data. After the blue data write cycle, the three bytes of
color are concatenated into a 24-bit word and written to the color palette RAM location specified by the
address register. The address register then increments to point to the next color palette RAM location, which
the MPU may modify by simply writing another sequence of red, green, and blue data bytes. A block of color
values in consecutive locations may be written to by writing the start address and performing continuous
red, green, and blue write cycles until the entire block has been written.
2.2.2
Reading From the Color Palette RAM
Reading from the color palette RAM is performed by writing the location to be read to the address register.
This action initiates a transfer from the color palette RAM into the holding register followed by an increment
of the address register. Three successive MPU reads from the holding register produce red, green, and blue
color data (6 or 8 bits, depending on the 8/6 mode) for the specified location. Following the blue read cycle,
the contents of the color palette RAM at the address specified by the address register are copied into the
holding register and the address register is again incremented. As with writing to the color palette RAM, a
block of color values in consecutive locations may be read by writing the start address and performing
continuous red, green, and blue read cycles until the entire block has been read.
2.2.3
Palette Page Register
The 8-bit palette page register provides high-speed color changing by removing the need for color palette
RAM reloading. When using 1, 2, or 4 bit-planes, the additional planes are provided by the palette page
register; e.g., when using four bit-planes, the pixel inputs specify the lower four bits of the color palette RAM
address with the upper four bits being specified by the palette register. This provides the capability of
selecting from 16 palette pages with only one chip access, thus allowing all the screen colors to be changed
at the line frequency. A bit-to-bit correspondence is used; therefore, in the above configuration, palette page
register bits 7 – 4 map onto color palette RAM address bits 7 – 4 respectively. This is listed in Table 2–2.
Since there is only one bit of overlay data in the 5-5-5 true color modes, the page register fills the seven
remaining MSBs (same as one bit-plane in Table 2–2). All 8 bits need to be cleared to 0 in order to enable
true color.
The additional bits from the palette page register are inserted before the read mask and hence, are subject
to masking.
Table 2–2. Allocation of Palette Page Register Bits
COLOR PALETTE RAM ADDRESS BITS
NUMBER OF
BIT PLANES
MSB
8
M
M
M
M
4
P7
P6
P5
P4
2
P7
P6
P5
P4
1
P7
P6
P5
P4
P3
LSB
M
M
M
M
M
M
M
M
P3
P2
M
M
P2
P1
M
Pn = nth bit from palette page register
M = bit from pixel port
2.3
Input/Output Clock Selection and Generation
The TLC34076 provides a maximum of five clock inputs. Three are dedicated to TTL inputs; the other two
can be selected as either one ECL input or two extra TTL inputs. The TTL and ECL inputs can be used for
video rates up to 135 MHz. The dual-mode clock input (ECL/TTL) is primarily an ECL input but can be used
2–2
as a TTL-compatible input when the input clock selection register is so programmed. The clock source used
at power-up is CLK0; an alternative source can be selected by software during normal operation. This
chosen clock input is used unmodified as the dot clock (representing the pixel rate to the monitor). The
device does, however, allow for user programming of the SCLK and VCLK outputs (shift and video clocks)
using the output clock selection register. The input/output clock selection registers are shown in Tables 2– 3,
2– 4, and 2– 5.
Table 2–3. Input Clock Selection Register Format
BITS†
FUNCTION‡
3
2
1
0
0
0
0
0
Select CLK0 as clock source§
0
0
0
1
Select CLK1 as clock source
0
0
1
0
Select CLK2 as clock source
0
0
1
1
Select CLK3 as TTL clock source
0
1
0
0
Select CLK3 as TTL clock source
1
0
0
0
Select CLK3 and CLK3 as ECL clock sources
† Register bits 4, 5, 6, and 7 are don’t care bits.
‡ When the clock selection is altered, a minimum 30-ns delay is incurred before the
new clocks are stabilized and running.
§ CLK0 is chosen at power-up to support the VGA pass-through mode.
Table 2–4. Output Clock Selection Register Format
BITS †
FUNCTION‡
5
4
3
2
1
0
0
0
0
X
X
X
VCLK frequency = DOTCLK frequency
0
0
1
X
X
X
VCLK frequency = DOTCLK frequency/2
0
1
0
X
X
X
VCLK frequency = DOTCLK frequency/4
0
1
1
X
X
X
VCLK frequency = DOTCLK frequency/8
1
0
0
X
X
X
VCLK frequency = DOTCLK frequency/16
1
0
1
X
X
X
VCLK frequency = DOTCLK frequency/32
1
1
X
X
X
X
VCLK output held at logic high level (default condition)§
X
X
X
0
0
0
SCLK frequency = DOTCLK frequency
X
X
X
0
0
1
SCLK frequency = DOTCLK frequency/2
X
X
X
0
1
0
SCLK frequency = DOTCLK frequency/4
X
X
X
0
1
1
SCLK frequency = DOTCLK frequency/8
X
X
X
1
0
0
SCLK frequency = DOTCLK frequency/16
X
X
X
1
0
1
SCLK frequency = DOTCLK frequency/32
SCLK output held at logic level low (default condition)§
† Register bits 6 and 7 are don’t care bits.
‡ When the clock selection is altered, a minimum 30-ns delay is incurred before the new clocks are stabilized
and running.
§ These lines indicate the power-up conditions required to support the VGA pass-through mode.
X
X
X
1
1
X
2–3
Table 2–5. VCLK/SCLK Divide Ratio Selectio (Output Clock Selection Register Value in Hex)
SCLK
BITS
2. . .0{
000
001
010
011
100
101
5. . .3{
divide
DOTCLK
by
1
2
4
8
16
32
000
1
00
01
02
03
04
05
001
2
08
09
0A
0B
0C
0D
010
4
10
11
12
13
14
15
1D
VCLK
BITS
011
8
18
19
1A
1B
1C
100
16
20
21
22
23
24
25
101
32
28
29
2A
2B
2C
2D
† Output clock selection register bits
The ECL input can be used as a differential or single-ended input. When the CLK3 input is used as a
single-ended ECL input, CLK3 must be externally terminated to set the input common-mode signal level.
This can be done with a simple resistor divider, as is the case with fully differential ECL.
SCLK is designed to drive the VRAMs directly, and VCLK is designed to work with video control signals like
BLANK and SYNC. While SCLK and VCLK are designed as a general-purpose shift clock and video clock,
respectively, they also interface directly with the TMS340x0 graphics signal processor (GSP) family directly.
Even though SCLK and VCLK can be selected independently, there is still a relationship between the two
as discussed in subsequent paragraphs. Many system considerations have been carefully covered in the
design, leaving maximum freedom to the user.
Internally, both SCLK and VCLK are generated from a common clock counter that increments on the rising
edge of the DOTCLK. Therefore, when VCLK is enabled, it is in phase with SCLK (see Figure 2–1).
DOTCLK
VCLK
(DOTCLK/4
as an example)
SCLK
(DOTCLK/2
as an example)
Figure 2–1. DOTCLK/VCLK/SCLK Relationship
The internal clock counter is reset to 0 any time the output clock-selection register (bits 5, 4, 2, 1) are all set
to 1. This provides a simple mechanism to synchronize multiple VIPs, by providing a known phase
relationship for the various system clocks. One can write directly to the Output Clock Selection register to
cause this to occur, or any of the various resets (for POR, hardware, and software, see Section 1.5) also
causes the appropriate bits to be written and the counters to reset. It is up to the user to provide some means
of disabling the dot-clock input to the part while this reset is occurring, when multiple parts are to be
synchronized.
Appendix A discusses the SCLK/VCLK relationship specific to the TMS340x0 GSP.
2–4
2.3.1
SCLK
Data is latched inside the device on the rising edge of LOAD, which is basically the same as SCLK but not
disabled during Blank active period. Therefore, SCLK must be set as a function of the pixel bus width and
the number of bit planes. SCLK can be selected as 1, 2, 4, 8, 16, or 32 divisions of the dot clock. When SCLK
is not used, the output is switched off and held low to protect against VRAM lock-up due to invalid SCLK
frequencies. SCLK is also held low during the Blank active period. The SCLK control timing has been
designed to interface directly with the external system VRAM. The shift register in the system VRAM should
be updated during the Blank active period. This allows the first SCLK out of Blank to clock the VRAM and
enable the first group of pixel data to appear on the pixel bus, as well as at the TLC34076 pixel input port.
The second SCLK after Blank latches the first group of pixel port data into the TLC34076.
The trailing edge of VCLK is used internally by the TLC34076 to sample and latch the BLANK input. When
BLANK becomes active, SCLK is disabled as soon as possible. For example, when SCLK is high and the
sampled BLANK goes low, SCLK is allowed to complete the clock cycle and return to the low state. SCLK
is then held low until the sampled BLANK signal goes high. At this time, SCLK is enabled to clock the VRAM
again. The TLC34076 video blanking circuitry is designed with sufficient pipeline delay to allow the internally
sampled BLANK signal to align with the pipelined RGB data to the video DACs. The logic described herein
works in situations where the SCLK period is shorter than, equal to, or longer than the VCLK period.
When the VRAM split shift-register operation is performed, the SCLK timing is adjusted to work with the
SFLAG input. Basically, the split shift register operation inserts a SCLK during the Blank period. This causes
the first group of pixel data to appear at the pixel port during the Blank signal. The first SCLK after Blank
then latches this data into the TLC34076. Figure 2–3 shows the case when the split shift register transfer
(SSRT) function is enabled. When a rising edge occurs on the SFLAG input, one SCLK with a minimum of
15-ns pulse duration is generated after the specified delay. Since this is designed to meet VRAM timing
requirements, the SSRT-generated SCLK replaces the first SCLK in the regular shift register transfer case
as previously described (see to Section 2.9 for a detailed explanation of the SSRT function).
The default divide ratio for SCLK is 1:1 as used in mode 0.
Depending on the frequency relationship between SCLK and VCLK, their phase relationship could be critical
(see Appendix C for a more detailed discussion).
2–5
2.3.2
VCLK
The VCLK frequency can be selected to be 1:1, 1:2, 1:4, 1:8, 1:16, or 1:32 of that of the dot clock, or it can
be held at a high logic level, which is the VCLK default condition. VCLK is not used in VGA pass-through
mode.
VCLK is used by a GSP or custom-designed control logic to generate control signals (BLANK, HSYNC, and
VSYNC). As can be seen from Figures 2– 2, 2– 3, 2– 4, and 2– 5, since the control signals are sampled by
VCLK, it is obvious that VCLK has to be enabled.
VCLK
BLANK
at Input Terminal
Latch Last Group
of Pixel Data
Latch First Group
of Pixel Data
Latch Last Group
of Pixel Data
Load
(Internal Signal
for Data Latch)
Blank
(Internal Signal
Before DOTCLK
Pipeline Delay)
Pixel Data
at Input Terminal
2nd
4th
1st Group 3rd Group 5th
Group
Group
Group
6th
Group
Last Group of Pixel Data
SCLK
NOTE A: Either the SSRT function is disabled (general control register bit 2 = 0), or the SFLAG/NFLAG input is held
low when the SSRT function is enabled (general-control register bit 2 = 1).
Figure 2–2. SCLK/VCLK Control Timing (SSRT Disabled,
SCLK Frequency = VCLK Frequency)
2–6
VCLK
BLANK
at Input Terminal
SFLAG/NFLAG
Latch Last Group
of Pixel Data
Latch First Group
of Pixel Data
Latch Last Group
of Pixel Data
Load
(Internal Signal
for Data Latch)
Blank
(Internal Signal
Before DOTCLK
Pipeline Delay)
Pixel Data
at Input Terminal
3rd
5th
2nd Group 4th Group
Group
Group
Last
Group
6th
Group
1st Group of Pixel Data
SCLK Between Split Shift Register Transfer
and Regular Shift Register Transfer
SCLK
NOTE A: The SSRT function is enabled (general control register bit 2 = 1).
Figure 2–3. SCLK/VCLK Control Timing (SSRT Enabled,
SCLK Frequency = VCLK Frequency)
VCLK
BLANK
at Input Terminal
Latch Last Group
of Pixel Data
Latch First Group
of Pixel Data
Load
(Internal Signal
for Data Latch)
Blank
(Internal Signal
Before DOTCLK
Pipeline Delay)
Pixel Data
at Input Terminal
2nd
4th
6th
1st Group 3rd Group 5th
Group
Group
Group
Group
Last Group of Pixel Data
SCLK
Figure 2–4. SCLK/VCLK Control Timing (SSRT Disabled,
SCLK Frequency = 4 × VCLK Frequency)
2–7
VCLK
BLANK
at Input Terminal
SFLAG/NFLAG
Latch Last Group
of Pixel Data
Latch First Group
of Pixel Data
Load
(Internal Signal
for Data Latch)
Blank
(Internal Signal
Before DOTCLK
Pipeline Delay)
3rd
5th
2nd Group 4th Group 6th
Group
Group
Group
Last
Group
Pixel Data
at Input Terminal
1st Group of Pixel Data
SCLK Between Split Shift-Register
and Regular Shift Register Transfer
SCLK
NOTE A: Either the SSRT function is disabled (general-control register bit 2 = 0), or the SFLAG/NFLAG input is held
low when the SSRT function is enabled (general-control register bit 2 = 1).
Figure 2–5. SCLK/VCLK Control Timing (SSRT Enabled,
SCLK Frequency = 4 × VCLK Frequency)
2.4
Multiplexing Scheme
The TLC34076 offers a highly versatile multiplexing scheme as illustrated in Table 2–6. The on-chip
multiplexing allows the system to be reconfigured to the amount of RAM available. For example, when only
256K bytes of memory are available, an 800-by-600 resolution mode with four bit-planes (4 bits per pixel)
can be implemented using an 8-bit wide pixel bus. If, at a later date, another 256K bytes are added to another
8 bits of the pixel bus, the user has the option of using eight bit-planes at the same resolution or four
bit-planes at a 1024 × 768 resolution. When an additional 512K bytes are added to the remaining 16 bits
of the pixel bus, the user has the option of eight bit-planes at 1024 × 768 resolution or four bit-planes at
1280 × 1024 resolution. All the above can be achieved without any hardware modification and without any
increase in the speed of the pixel bus.
2–8
Table 2–6. Mode and Bus Width Selection
MUX CONTROL REGISTER BITS†
5
4
3
2
1
0
DATA BITS
PER
PIXEL‡
1
0
1
1
0
1
8
8
1
1) VGA7 – VGA0
0
1
0
0
0
0
1
4
4
1)
2)
3)
4)
0
1
0
0
0
1
1
8
8
1) P0
2) P1 .
.
.
8) P7
0
1
0
0
1
0
1
16
16
1) P0
2) P1 .
.
.
16) P15
0
1
0
0
1
1
1
32
32
1) P0
2) P1 .
.
.
32) P31
0
1
0
1
0
0
2
4
2
1) P1 – P0
2) P3 – P2
0
1
0
1
0
1
2
8
4
1)
2)
3)
4)
0
1
0
1
1
0
2
16
8
1) P1 – P0
2) P3 –. P2
.
.
8) P15 – P14
0
1
0
1
1
1
2
32
16
1) P1 – P0
2) P3 –. P2
.
.
16) P31 – P30
MODE
0#
1
2
PIXEL BUS
WIDTH
SCLK
DIVIDE
RATIO§
PIXEL
LATCHING
SEQUENCE¶
P0
P1
P2
P3
P1 – P0
P3 – P2
P5 – P4
P7 – P6
† Bits 6 and 7 are don’t care bits.
‡ This is the number of bits of pixel port (or VGA port in mode 1) information used as color data for each displayed pixel,
often referred to as the number of bit planes. This may be color palette address data (modes 0 – 5) or DAC data
(mode 6).
§ The SCLK divide ratio is the number used for the output clock selection register. It indicates the number of pixels per
bus load, or the number of pixels associated with each SCLK pulse. For example, with a 32-bit pixel bus width and 8
bit-planes, 4 pixels comprise each bus load. The SCLK divide ratio is not automatically set by mode selection, but must
be written to the output clock selection register.
¶ For each operating mode, the pixel latching sequence indicates the sequence in which pixel port or VGA port data are
latched into the device. The latching sequence is initiated by a rising edge on SCLK. For modes in which multiple groups
of data are latched, the SCLK rising edge latches all the groups, and the pixel clock shifts them out starting with the
low-numbered group. For example, in mode 3 with a 16-bit pixel bus width, the rising edge of SCLK latches all the data
groups, and the pixel clock shifts them out in the order P3 – P0, P7 – P4, P11 – P8, and P15 – 12 terminals.
# Mode 0 is the VGA pass-through mode.
NOTE 1: Although leaving unused pins floating does not adversely affect device operation, tying unused pins to ground
lowers power consumption and, thus, is recommended.
2–9
Table 2–6. Mode and Bus Width Selection (Continued)
MUX CONTROL REGISTER BITS†
5
4
3
2
1
0
DATA BITS
PER
PIXEL‡
0
1
1
0
0
0
4
4
1
1) P3 – P0
0
1
1
0
0
1
4
8
2
1) P3 – P0
2) P7 – P4
0
1
1
0
1
0
4
16
4
1)
2)
3)
4)
0
1
1
0
1
1
4
32
8
1) P3 – P0
2) P7 – P4
MODE
PIXEL BUS
WIDTH
SCLK
DIVIDE
RATIO§
3
PIXEL
LATCHING
SEQUENCE¶
P3 – P0
P7 – P4
P11 – P8
P15 – P12
8) P31 – P28
4
0
1
1
1
0
0
8
8
1
1) P7 – P0
0
1
1
1
0
1
8
16
2
1) P7 – P0
2) P15 – P8
0
1
1
1
1
0
8
32
4
1)
2)
3)
4)
P7 – P0
P15 – P8
P23 – P16
P31 – P24
† Bits 6 and 7 are don’t care bits.
‡ This is the number of bits of pixel port (or VGA port in mode 1) information used as color data for each displayed pixel,
often referred to as the number of bit-planes. This may be color palette address data (modes 0 – 5) or DAC data
(mode 6).
§ The SCLK divide ratio is the number used for the output clock selection register. It indicates the number of pixels per
bus load, or the number of pixels associated with each SCLK pulse. For example, with a 32-bit pixel bus width and 8
bit-planes, four pixels comprise each bus load. The SCLK divide ratio is not automatically set by mode selection, but
must be written to the output clock selection register.
¶ For each operating mode, the pixel latching sequence indicates the sequence in which pixel port or VGA port data are
latched into the device. The latching sequence is initiated by a rising edge on SCLK. For modes in which multiple groups
of data are latched, the SCLK rising edge latches all the groups, and the pixel clock shifts them out starting with the
low-numbered group. For example, in mode 3 with a 16-bit pixel bus width, the rising edge of SCLK latches all the data
groups, and the pixel clock shifts them out in the order P3 – P0, P7 – P4, P11 – P8, P15 – P12.
NOTE 1: Although leaving unused pins floating does not adversely affect device operation, tying unused pins to ground
lowers power consumption and, thus, is recommended.
2–10
Table 2–6. Mode and Bus Width Selection (Continued)
MUX CONTROL REGISTER BITS†
5
4
3
2
1
0
DATA BITS
PER
PIXEL‡
0
1
1
1
1
1
4
MODE
PIXEL BUS
WIDTH
SCLK
DIVIDE
RATIO§
16
4
PIXEL
LATCHING
SEQUENCE¶
NFLAG = 0:
1) P3 – P0
2) P11 – P8
3) P19 – P16
4) P27 – P24
5#
NFLAG = 1:
1) P7 – P4
2) P15 – P12
3) P23 – P20
4) P31 – P28
6||
See Table 2–7 and Table 2–8
† Bits 6 and 7 are don’t care bits.
‡ This is the number of bits of pixel port (or VGA port in mode 1) information used as color data for each displayed pixel,
often referred to as the number of bit-planes. This may be color palette address data (modes 0 – 5) or DAC data
(mode 6).
§ The SCLK divide ratio is the number used for the output clock selection register. It indicates the number of pixels per
bus load, or the number of pixels associated with each SCLK pulse. For example, with a 32-bit pixel bus width and 8
bit-planes, 4 pixels comprise each bus load. The SCLK divide ratio is not automatically set by mode selection, but must
be written to the output clock selection register.
¶ For each operating mode, the pixel latching sequence indicates the sequence in which pixel port or VGA port data are
latched into the device. The latching sequence is initiated by a rising edge on SCLK. For modes in which multiple groups
of data are latched, the SCLK rising edge latches all the groups, and the pixel clock shifts them out starting with the
low-numbered group. For example, in mode 3 with a 16-bit pixel bus width, the rising edge of SCLK latches all the data
groups, and the pixel clock shifts them out in the order P3 – P0, P7 – P4, P11 – P8, P15 – P12.
# Mode 5 is special nibble mode, the only mode in which the pixel bus width is not equal to the actual physical width, in
bits, of the pixel bus. In this mode, the pixel bus is physically 32 bits wide; depending on the value of SFLAG/NFLAG,
either the upper or lower nibble of each of the four physical bytes is selected to comprise the 16 bits of pixel data (equal
to four 4-bit pixels).
|| Mode 6 is true color mode, in which 24 bits of color information are transferred directly from the pixel port to the DACs;
overlay is implemented with the remaining eight bits of the pixel bus. The distribution of pixel port data to the DACs is
as follows: P31 – P24 are passed to the blue DAC, P23 – P16 are passed to the green DAC, and P15 – P8 are passed
to the red DAC. P7 – P0 generate overlay data; this operation can be disabled by either grounding P7 – P0 or by clearing
the read mask (see subsection 2.4.6).
NOTE 1: Although leaving unused pins floating will not adversely affect device operation, tying unused pins to ground
lowers power consumption and, thus, is recommended.
2.4.1
VGA Pass-Through Mode
Mode 0, the VGA pass-through mode, emulates the VGA modes of most personal computers. The
advantage of this mode is that the TLC34076 can take data presented on the feature connectors of most
VGA-compatible PC systems into the device on a separate bus, thus requiring no external multiplexing. This
feature is particularly useful for systems in which the existing graphics circuitry is on the motherboard. In
this instance, it enables implementation of a drop-in graphics card that maintains compatibility with all
existing software by using the on-board VGA circuitry but routing the emerging bit-plane data through the
TLC34076. This is the default mode at power-up. When the VGA pass-through mode is selected after the
device is powered up, the clock selection register, the general control register, and the pixel read mask
register are set to their default states automatically.
2–11
Since this mode is designed with the feature connector philosophy, all the timing is referenced to CLK0,
which is used by default for the VGA pass-through mode. For all the other normal modes, CLK0 – CLK3 are
the oscillator sources for DOTCLK, VCLK, and SCLK; all the data and control timing is referenced to SCLK.
2.4.2
Multiplexing Modes
In addition to the VGA pass-through mode, there are four multiplexing modes available, all of which are
referred to as normal modes. In each normal mode, a pixel bus width of 8, 16, or 32 bits may be used. Modes
1, 2, and 3 also support a pixel bus width of 4 bits. Data should always be presented on the least significant
bits of the pixel bus. For example, when a 16-bit-wide pixel bus is used and there are 8 bits per pixel, each
8-bit pixel should be presented on P0 – P7. All the unused pixel bus terminals should be connected to GND.
Mode 1 uses a single bit-plane to address the color palette. The pixel port bit is fed into bit 0 of the palette
address, with the seven high-order address bits being defined by the palette page register (see subsection
2.2.3). This mode has uses in high-resolution monochrome applications such as desktop publishing. This
mode allows the maximum amount of multiplexing (a 32:1 ratio), thus giving a pixel bus rate of only 4 MHz
at a screen resolution of 1280 1024 pixels. Although only a single-bit plane is used, alteration of the palette
page register at the line frequency allows 256 different colors to be displayed simultaneously with two colors
per line.
Mode 2 uses two bit-planes to address the color palette. The 2 bits are fed into the low-order address bits
of the palette with the six high-order address bits being defined by the palette page register. This mode
allows a maximum divide ratio of 16:1 on the pixel bus and is a 4-color alternative to mode 1.
Mode 3 uses four bit-planes to address the color palette. The 4 bits are fed into the low-order address bits
of the palette with the four high-order address bits being defined by the palette page register. This mode
provides 16 pages of 16 colors and can be used at SCLK divide ratios of 1:8.
Mode 4 uses eight bit-planes to address the color palette. Since all 8 bits of palette address are specified
from the pixel port, the page register is not used. This mode allows dot-clock-to-SCLK ratios of 1:1 (8-bit
bus), 2:1 (16-bit bus) or 4:1 (32-bit bus). Therefore, in a 32-bit configuration, a 1024 768 pixel screen can
be implemented with an external data rate of only 16 MHz.
All normal multiplexing modes can support little-endian (default) and big-endian data formats at the pixel
bus inputs (see subsection 2.6.1).
2.4.3
Special Nibble Mode
Mode 5 is the special nibble mode, which is enabled when the general-control register SNM bit 3 is set to
1 and the general-control register SSRT bit 2 is cleared to 0 (see Section 2.11). When the special nibble
mode is enabled, it takes precedence over the other modes, and the mux control register setup is ignored.
The SFLAG/NFLAG input is then used as a nibble flag to indicate which nibble of each byte holds the pixel
data. Special-nibble mode is a variation of the 4-bit pixel mode with a 16-bit pixel width. All 32 inputs
(P0 P31) are connected as four bytes, but the 16-bit data bus is composed of either the lower or upper
nibble of each of the four bytes (for more detailed information, see subsection 2.9.2). Since this mode uses
four bit-planes for each pixel, they are fed into the low-order address bits of the palette, with the 4 high-order
address bits being defined by the palette page register (see subsection 2.2.3).
*
2.4.4
True-Color Modes
Mode 6 is the true-color mode in which 24, 16, or 15 bits of data are transferred from the pixel port directly
to the DACs, but with the same amount of pipeline delay as the overlay data and the control signals (BLANK
and Sync). Depending on which true-color mode is selected, overlay is provided by utilizing the remaining
bits of the pixel bus to address the palette RAM (see Tables 2–6 and 2–7). This results in a 24-bit RAM output
that is then used as overlay information to the DACs. When all of the overlay inputs are cleared to 0, no
overlay information is displayed. When a nonzero value is input, the color palette RAM is addressed and
the resulting data is then fed through to the DACs and receives priority over the true-color data.
2–12
Table 2–7. True-Color Modes
MUX CONTROL REGISTER BITS†
5
4
3
2
1
0
DATA
BITS PER
PIXEL‡
6a
0
0
1
0
0
0
15
16
1
1
1) P15 – P0
6b
0
0
1
0
0
1
16
16
1
N/A
1) P15 – P0
6c
0
0
1
0
1
0
15
32
2
1
1) P15 – P0
2) P31 – P16
6d
0
0
1
0
1
1
16
32
2
N/A
1) P15 – P0
2) P31 – P16
6e
0
0
1
1
1
0
24
32
1
8
1) P31 – P0
6f
0
0
1
1
0
1
24
32
1
8
MODE
PIXEL
BUS
WIDTH
SCLK
DIVIDE
RATIO§
OVERLAY
BITS PER
PIXEL (4)
PIXEL
LATCHING
SEQUENCE¶
6#
1) P31 – P0
† Bits 6 and 7 are don’t care bits.
‡ This is the number of bits of pixel port (or VGA port in mode 1) information used as color data for each displayed pixel,
often referred to as the number of bit-planes. This may be color palette address data (modes 0 – 5) or DAC data
(mode 6).
§ The SCLK divide ratio is the number used for the output clock selection register. It indicates the number of pixels per
bus load, or the number of pixels associated with each SCLK pulse. For example, with a 32-bit pixel bus width and eight
bit-planes, four pixels comprise each bus load. The SCLK divide ratio is not automatically set by mode selection, but
must be written to the output clock selection register.
¶ For each operating mode, the pixel latching sequence indicates the sequence in which pixel port or VGA port data are
latched into the device. The latching sequence is initiated by a rising edge on SCLK. For modes in which multiple groups
of data are latched, the SCLK rising edge latches all the groups, and the pixel clock shifts them out starting with the
low-numbered group. For example, in mode 6d with a 32-bit pixel bus width, the rising edge of SCLK latches all the data
groups, and the pixel clock shifts them out in the order P15 – P0 and P31 – P16.
# Mode 6 is true-color mode in which 24 bits of color information are transferred directly from the pixel port to the DACs;
overlay is implemented with the remaining 8 bits of the pixel bus. The distribution of pixel port data to the DACs is as
follows: P31 – P24 are passed to the blue DAC, P23 – P16 are passed to the green DAC, and P15 – P8 are passed
to the red DAC. P7 – P0 generate overlay data; this operation can be disabled by either grounding P7 – P0 or by clearing
the read mask (see subsection 2.4.6).
NOTE 1: Although leaving unused terminals floating does not adversely affect device operation, tying unused terminals
to ground lowers power consumption and is recommended.
2–13
Mode 6a is the TARGA compatible (5-5-5) true-color mode. In this 16-bit mode, there are 5 bits of red, 5 bits
of green, 5 bits of blue, and an additional overlay bit (see Table 2–8 for the bit definitions).
Table 2–8. True-Color Bit Definitions
Little Endian
PIXEL BUS
P31
P30
P29
P28
P27
P26
P25
P24
P23
P22
P21
P20
P19
P18
P17
P16
DATA BUS
D31
D30
D29
D28
D27
D26
D25
D24
D23
D22
D21
D20
D19
D18
D17
D16
O
R4
R3
R2
R1
R0
G4
G3
G2
G1
G0
B4
B3
B2
B1
B0
a
b
c
d
R4
R3
R2
R1
R0
G5
G4
G3
G2
G1
G0
B4
B3
B2
B1
B0
e
O7
O6
O5
O4
O3
O2
O1
O0
R7
R6
R5
R4
R3
R2
R1
R0
f
B7
B6
B5
B4
B3
B2
B1
B0
G7
G6
G5
G4
G3
G2
G1
G0
PIXEL BUS
P15
P14
P13
P12
P11
P10
P9
P8
P7
P6
P5
P4
P3
P2
P1
P0
DATA BUS
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
a
O
R4
R3
R2
R1
R0
G4
G3
G2
G1
G0
B4
B3
B2
B1
B0
b
R4
R3
R2
R1
R0
G5
G4
G3
G2
G1
G0
B4
B3
B2
B1
B0
c
O
R4
R3
R2
R1
R0
G4
G3
G2
G1
G0
B4
B3
B2
B1
B0
d
R4
R3
R2
R1
R0
G5
G4
G3
G2
G1
G0
B4
B3
B2
B1
B0
e
G7
G6
G5
G4
G3
G2
G1
G0
B7
B6
B5
B4
B3
B2
B1
B0
f
R7
R6
R5
R4
R3
R2
R1
R0
O7
O6
O5
O4
O3
O2
O1
O0
PIXEL BUS
P31
P30
P29
P28
P27
P26
P25
P24
P23
P22
P21
P20
P19
P18
P17
P16
DATA BUS
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
D10
D11
D12
D13
D14
D15
Big Endian
a
b
c
B0
B1
B2
B3
B4
G0
G1
G2
G3
G4
R0
R1
R2
R3
R4
O
d
B0
B1
B2
B3
B4
G0
G1
G2
G3
G4
G5
R0
R1
R2
R3
R4
e
B0
B1
B2
B3
B4
B5
B6
B7
G0
G1
G2
G3
G4
G5
G6
G7
f
O0
O1
O2
O3
O4
O5
O6
O7
R0
R1
R2
R3
R4
R5
R6
R7
PIXEL BUS
P15
P14
P13
P12
P11
P10
P9
P8
P7
P6
P5
P4
P3
P2
P1
P0
DATA BUS
D16
D17
D18
D19
D20
D21
D22
D23
D24
D25
D26
D27
D28
D29
D30
D31
a
B0
B1
B2
B3
B4
G0
G1
G2
G3
G4
R0
R1
R2
R3
R4
O
b
B0
B1
B2
B3
B4
G0
G1
G2
G3
G4
G5
R0
R1
R2
R3
R4
c
B0
B1
B2
B3
B4
G0
G1
G2
G3
G4
R0
R1
R2
R3
R4
O
d
B0
B1
B2
B3
B4
G0
G1
G2
G3
G4
G5
R0
R1
R2
R3
R4
e
R0
R1
R2
R3
R4
R5
R6
R7
O0
O1
O2
O3
O4
O5
O6
O7
f
G0
G1
G2
G3
G4
G5
G6
G7
B0
B1
B2
B3
B4
B5
B6
B7
Mode 6b is the XGA compatible (5-6-5) true-color mode. This 16-bit mode has 5 bits of red, 6 bits of green,
and 5 bits of blue data. The overlay function is not enabled in this mode (see Table 2–8 for the exact bit
definitions).
Mode 6c is a multiplexed version of mode 6a that allows two 16-bit TARGA-compatible words to be latched
into the TLC34076 pixel port with one SCLK. In this mode, the 16-bit word latched on pixel port inputs
2–14
P0 – P15 is executed first, while the word latched on P16 – P31 is executed last. The user should program
the SCLK divide ratio in the output-clock selection register to divide by two (see Table 2–8 for the exact bit
definitions).
Mode 6d is a multiplexed version of mode 6b that allows two 16-bit XGA-compatible words to be latched
into the TLC34076 pixel port with one SCLK. In this mode, the 16-bit word latched on pixel port inputs
P0 – P15 is executed first, while the word latched on P16 – P31 is executed last. The user should program
the SCLK divide ratio in the output-clock selection register to divide by 2 (see Table 2–8 for the bit definitions).
Mode 6e is a 24-bit true-color mode that features 8 bits of data for each color, as well as 8 bits of overlay
information. The order in which the color and overlay fields appear in the 32-bit word are the reverse of
mode 6f (see Table 2–8 for the bit definitions).
Mode 6f is the 24-bit true-color mode used on the TLC34076. It also features 8 bits of data for each color,
as well as 8 bits of overlay information (see Table 2–8 for the bit definitions).
Since only 5 bits (6 bits for green in mode 6b and 6d) are provided for each color in the 16-bit true-color
modes (6a–6d), the color data is internally shifted by the TLC34076 to the five MSB positions (six MSB
positions for green in modes 6b and 6d) before being presented to the 3-color DACs. The remaining lower
3 bits (lower 2 bits for green in modes 6b and 6d) then clear to 0.
When in true-color modes 6a or 6c, the internal palette page register fills the remaining seven MSBs of
overlay data (see subsection 2.2.3). This occurs in these modes because there is only 1 bit of overlay
information presented in the true-color word. In order to enable the true-color data to the DACs, all 8 overlay
bits must be reset to 0. This can be accomplished by either writing zeros to the internal palette page register
and the overlay bit, or by writing zeros to the internal read mask (see subsection 2.4.6).
When in true-color modes 6e or 6f, the data input only works in the 8-bit mode. In other words, when only
6 bits are to be used, the two LSB inputs for each color must be tied to GND. However, the palette, which
is used by the overlay input, is still governed by 8/6-input terminal and the output multiplexer (MUX) selects
8-bit data or 6-bit data accordingly. The 8/6-input terminal is also valid in the other 16-bit modes as well.
Both little-endian (default) and big-endian data formats are supported by the true-color modes (see
subsection 2.6.1 and Table 2–8 for more information).
2.4.5
Multiplex Control Register
The MUX is controlled using the 8-bit mux control register. The bit fields of the register are in Table 2– 6 and
Table 2–7.
As an example of how to use Table 2– 6, suppose that the design goals specify a system with 8 data bits
per pixel and the lowest possible SCLK rate. Table 2– 6 shows that, for non-VGA pass-through operation,
only mode 4 supports an 8-bit pixel depth. The lowest possible SCLK rate within mode 4 is 1:4. This set of
conditions are selected by writing the value 1Eh to the mux control register. The pixel latching sequence
column shows that, in this mode, pixel-input ports P7 – P0 should be connected to the earliest displayed
pixel plane, followed by P15 – P8, P23 – P16, and then P31 – P24 as the last displayed pixel plane. Assuming
that VCLK is programmed as DOTCLK/4, Table 2– 5 shows that the 1:4 SCLK ratio is selected by writing
the value 12h to the output clock selection register. The special nibble mode should also be disabled (see
subsections 2.9.2 and 2.11.2).
When the mux control register is loaded with 2Dh, the TLC34076 enters the VGA pass-through mode which
is the same condition as the default power-up mode. More details are given in subsection 2.5.4.
2–15
2.4.6
Read Masking
The read mask register enables or disables a pixel address bit from addressing the color palette RAM. Each
palette address bit is logically ANDed with the corresponding bit from the read mask register before
addressing the palette. This function is performed after the addition of the page register bits and, therefore,
a zeroing of the read mask results in one unique palette location (location 0) and is not affected by the palette
page register contents.
Note also that the read mask can zero the overlay data in the true-color modes. This is a handy way to
disable the overlay (enable true-color data to the DACs) for a whole screen.
2.5
Reset
There are three ways to reset the TLC34076:
2.5.1
•
Power-on reset
•
Hardware reset
•
Software reset
Power-On Reset
There is a power-on reset (POR) circuit built into the TLC34076. This POR works at power-on only. Even
though this circuitry is provided, it is still recommended for the user to design a hardware reset circuit to
ensure the reset condition after power-up as described in subsection 2.5.2.
Once the voltage is stabilized, the default condition for all registers is the VGA mode. When the TLC34076
is reset, the SCLK and VCLK counters are reset as well (see Section 2.3 and subsection 2.5.4).
2.5.2
Hardware Reset
The TLC34076 resets whenever RS3 – RS0 = HHHH and a rising edge occurs on WR input. Resetting of
the TLC34076 is most reliable when many rising WR edges occur during the time RS=HHHH. This scheme
(bursting WR strobes until the power supply voltage stabilizes) is suggested at power up when a hardware
reset approach is used.
The default reset condition is VGA mode, and the values for each register are shown in subsection 2.5.4.
Also when the TLC34076 is reset, the SCLK and VCLK counters are reset (see Section 2.3).
2.5.3
Software Reset
Whenever the mux control register is set for VGA pass-through mode after power up, all registers are
initialized accordingly. Since VGA pass-through mode is the default condition at power up and hardware
reset, the act of selecting the VGA pass-through mode through programming the mux control register is
viewed as a software reset. Therefore, whenever mux control register bits 5 – 0 are set to 2Dh, the
TLC34076 initiates a software reset. This also resets the SCLK and VCLK counters (see Section 2.3). This
is referred to as a software reset, since it is typically initiated by software, unlike POR or hardware resets.
2–16
2.5.4
VGA Pass-Through Mode Default Conditions
The value contained in each register after hardware or software reset is shown in Table 2–9.
Table 2–9. VGA Pass-Through Mode Default Conditions
REGISTER NAME
DEFAULT VALUE
Mux control register
2Dh
Input clock selection register
00h
Output clock selection register
3Fh
Palette page register
00h
General control register
03h
Pixel read mask register
FFh
Palette address register
xxh
Palette holding register
Test register
2.6
xxh
(Pointing to color palette red value)
Analog Output Specifications
The DAC outputs are controlled by current sources (three for IOG and two each for IOR and IOB) as shown
in Figure 2– 6. In the normal case, there is a 7.5-IRE (Institute of Radio Engineers: predecessor to the IEEE)
difference between Blank and Black levels, which is shown in Figure 2–7. When a 0-IRE pedestal is desired,
it can be selected by resetting bit 4 of the general control register (see subsection 2.11.3). The video output
for a 0-IRE pedestal is shown in Figure 2–8.
NOTE:
For a 75-Ω doubly terminated load, the VREF = 1.235 V, RSET = 523 Ω, RS-343A
levels and tolerances in recommended operating conditions are assumed.
VAA
IOG
∼ 15 pF
SYNC
(IOG Only)
BLANK
RL
G0 – G7
Figure 2–6. Equivalent Circuit of the IOG Current Output
2–17
White
Green
[mA]
[V]
Red/Blue
[mA]
[V]
26.67
1.000
19.05 0.714
9.05
0.340
1.44
0.054
7.62
0.286
0.00
0.000
0.00
0.000
92.5 IRE
Black
7.5 IRE
Blank
40 IRE
Sync
Figure 2–7. 7.5-IRE, 8-Bit Composite Video Output
White
Green
[mA]
[V]
Red/Blue
[mA]
[V]
25.24
0.95
17.62
0.66
7.62
0.286
0.00
0.000
0.00
0.000
100 IRE
Pedestal
Black/
Blank
Sync
43 IRE
Figure 2–8. 0-IRE, 8-Bit Composite Video Output
2–18
A resistor (RSET) is needed to connect FS ADJUST to GND to control the magnitude of the full-scale video
signal. The IRE relationships in Figures 2–7 and 2– 8 are maintained regardless of the full-scale output
current.
The relationship between RSET and the full-scale output current IOG is:
RSET (Ω) = K1 × VREF (V) / IOG (mA)
The full-scale output current on IOR and IOB for a given RSET is:
IOR, IOB (mA) = K2 × VREF (V) / RSET (Ω)
where K1 and K2 are defined as:
IRE LEVEL
2.7
IOG
8-BIT OUTPUT
IOR, IOB
6-BIT OUTPUT
8-BIT OUTPUT
6-BIT OUTPUT
7.5-IRE
K1 = 11,294
K1 = 11,206
K2 = 8,067
K2 = 7,979
0-IRE
K1 = 10,684
K1 = 10,600
K2 = 7,462
K2 = 7,374
Frame-Buffer Interface with Little-Endian and Big-Endian Modes
The TLC34076 provides two clock signals for controlling the frame-buffer interface. They are SCLK and
VCLK. SCLK can clock out data directly from the VRAM shift registers. Split shift-register transfer
functionality is also supported. VCLK clocks and synchronizes control inputs like HSYNC, VSYNC, and
BLANK.
The pixel data presented at the inputs is latched at the rising edge of SCLK in normal mode or the rising edge
of CLK0 in VGA pass-through mode. Control inputs HSYNC, VSYNC, and BLANK are sampled and latched
at the falling edge of VCLK in normal mode, while HSYNC, VSYNC, and VGABLANK are latched at the rising
edge of CLK0 in VGA pass-through mode. Both data and control signals are lined up at the DAC outputs
to the monitor through the internal pipeline delay, so external glue logic is not required. The outputs of the
DACs are capable of directly driving a 37.5-Ω load, as in the case of a doubly terminated 75-Ω cable (see
Figures 2–7 and 2– 8 for nominal output levels).
The frame-buffer interface (pixel bus) supports both little-endian and big-endian data formats for all normal
multiplexing and true-color modes of operation. The data-format mode select is controlled by General
Control register bit 6 (see Section 2.11). When GCR bit 6 is cleared to 0 (default), the format is set to the
little-endian mode. When GCR bit 6 is set to 1, the format is set to the big-endian mode.
In a big-endian mode design the external VRAM data bus bits must be connected in reverse order to the
TLC34076 pixel bus (i.e. D31 connected to P0, and D0 connected to P31, etc.). This ensures that the least
significant channel always provides the first pixel to be displayed in the normal multiplexing modes.
2.8
HSYNC, VSYNC, and BLANK
For the normal modes, HSYNC and VSYNC are active-low pulses, and they are passed through
true/complement gates to the HSYNCOUT and VSYNCOUT outputs. The output polarities of HSYNCOUT
and VSYNCOUT can be programmed through the general control register. However, for the VGA
pass-through mode, the polarities needed for monitors are already provided at the feature connector from
which HSYNC and VSYNC are sourced, so the TLC34076 passes HSYNC and VSYNC through to
HSYNCOUT and VSYNCOUT without polarity change. As described in Section 2.3 and Figures 2– 2
through 2– 5, the BLANK, HSYNC, and VSYNC inputs are sampled and latched on the falling edge of VCLK
in the normal modes, and they are latched on the rising edge of the CLK0 input in the VGA pass-through
mode (see Figure 3– 2 for the detailed timing).
2–19
The HSYNC and VSYNC inputs are used for both the VGA pass-through and normal modes. When the
application uses both VGA pass-through and normal modes, an external multiplexer is needed to select
HSYNC and VSYNC between the VGA pass-through mode and the normal mode. The MUXOUT signal is
designed for this purpose (see Sections 2.10 and 2.11).
The HSYNC, VSYNC, and BLANK signals have internal pipeline delays to align with the data at the DAC
outputs. Due to the sample and latch timing delay, it is possible to have active SCLK pulses after the BLANK
input becomes active. The relationship between VCLK and SCLK and the internal VCLK sample and latch
delay need to be carefully reviewed and programmed (see Section 2.3 and Figures 2–2 and 2–3 for more
details).
As shown in Figure 2– 6 for the IOG DAC output, active HSYNC and VSYNC signals turn off the sync current
source (after the pipeline delay) independent of the BLANK signal level. In real applications, HSYNC and
VSYNC should only be active (low) when BLANK is active (low).
To alter the polarity of the HSYNCOUT and VSYNCOUT outputs in the normal modes, the MPU must set
or clear the corresponding bits in the General Control register (see subsection 2.11.1). Again, these two bits
affect only the normal modes, not the VGA pass-through mode. These bits default to 1.
2.9
Split Shift Register Transfer VRAMs and Special Nibble Mode
The following paragraphs describe the operation of the split shift register when effecting a transfer from the
VRAMs, and the use of the special nibble mode. The special nibble mode provides a variation of the 4-bit
pixel mode with a 16-bit bus width.
2.9.1
Split Shift Register Transfer VRAMs
The TLC34076 directly supports split shift register transfer (SSRT) VRAMs. In order to allow the VRAMs
to perform a split shift-register transfer, an extra SCLK cycle must be inserted during the Blank sequence.
This is initiated when the SSRT enable bit is set to 1, the SNM bit is reset to 0 , and a rising edge on the
SFLAG/NFLAG input terminal is detected. An SCLK pulse is generated within 20 ns of the rising edge of
the SFLAG/NFLAG signal. A minimum 15-ns high logic level duration is provided to satisfy all of the 15-ns
VRAM requirements. By controlling the SFLAG/NFLAG rise time, the delay time from the rising edge of the
VRAM TRG signal to SCLK can be satisfied. The relationship between the SCLK, SFLAG/NFLAG, and
BLANK signals is shown in Figure 2-9.
BLANK
SSRT Enable
(General Control
Register Bit 2)
SFLAG/NFLAG
Input
SCLK
Figure 2–9. Relationship Between SFLAG/NFLAG, BLANK, and SCLK
When SFLAG/NFLAG is designed as an R-S latch set by split shift register transfer timing and reset by
BLANK going high, the delay from BLANK high to SFLAG/NFLAG low cannot exceed one-half of a SCLK
cycle; otherwise, the SCLK generation logic may fail.
2–20
When the SSRT function is enabled but SFLAG/NFLAG is held low, SCLK runs as if the SSRT function is
disabled. The SFLAG/NFLAG input is not qualified by the BLANK signal and needs to be held low whenever
an SSRT SCLK pulse is not desired (see subsection 2.3.1 and Figures 2–2 through 2– 8 for more system
details).
2.9.2
Special Nibble Mode
Special nibble mode is enabled when the SNM bit (bit 3 in the General Control register) is set to 1 and the
SSRT bit (bit 2 in the general control register) is reset to 0 (see Section 2.11). The special nibble mode
provides a variation of the 4-bit pixel mode with a 16-bit bus width. While all 32 inputs (P0 – P31) are
connected as four bytes, the 16-bit data bus is composed of the lower or upper nibble of each of the four
bytes, depending on the level of the SFLAG/NFLAG input. The pixel data is distributed to the 16-bit data
bus as shown in Table 2–10.
Table 2–10. Pixel Data Distribution in Special Nibble Mode
SNM BIT = 1, SSRT BIT = 0
SFLAG/NFLAG = 1
SFLAG/NFLAG = 0
P7 – P4
P15 – P12
P23 – P20
P31 – P28
P3 – P0
P11 – P8
P19 – P16
P27 – P24
The SFLAG/NFLAG value is not latched by the TLC34076; therefore, it should stay at the same level during
the whole active display period, changing levels only during the BLANK signal active time. (see to
Figure 2–10, which is similar to Figure 2–2 except that the BLANK signal timing reference to SFLAG/NFLAG
is explained). The SFLAG/NFLAG input has to meet the setup time and hold the data long enough to ensure
that no pixel data is missed.
CAUTION:
If pixel data are not held valid until both SCLK and BLANK go low, the last few
pixels can be missed.
2–21
VCLK
BLANK
(at its input pin)
(see Note A)
SFLAG/NFLAG
Input
Valid
(see Note B)
Don’t Care
Latch Last Group
of Pixel Data
Valid
Latch First Group
of Pixel Data
LOAD
Sampled
BLANK
PIXEL DATA
2nd
4th
1st Group 3rd Group 5th
Group
Group
Group
Last Group of Pixel Data
SCLK
NOTES: A. If the data is not held valid until SCLK and BLANK both go low, the last few pixels could be missed.
B. Setup time to the next VCLK falling edge after BLANK goes high must be met; otherwise, the first
pixel data could be missed.
Figure 2–10. SFLAG/NFLAG Timing in Special Nibble Mode
Special nibble mode operates at the line frequency when BLANK is active. However, the typical application
of this mode is double frame buffers with pixel data width of 4 bits. While one frame buffer is being displayed
on the monitor, the other frame buffer can accept new picture information. SFLAG/NFLAG indicates which
frame buffer is being displayed.
SNM and SSRT must be mutually exclusive. Unpredictable operation occurs when both the SNM and SSRT
bits are set to 1. The mux control register should be set up as shown in Table 2– 6. However, the SNM bit
takes precedence over the other mux control register selections. In other words, when the mux control
register is set up for another mode but special nibble mode is still enabled in the general control register,
the input multiplex circuit takes whatever SCLK divide ratio the mux control register specifies and performs
the nibble operation causing operational failure.
During special nibble mode, the input mux circuit latches all 8-bit inputs but only passes on the specified
nibble. The specified nibble is stored in the four LSBs of the next register pipe after the input latch, and the
four MSBs are cleared to 0 in that register. The register pipe contents are then passed to the read mask
block. With this structure, the palette page register still functions normally, providing good flexibility to users.
When the general control register bit 3 = 0 and bit 2 = 0, both split shift-register transfers and the special
nibble mode are disabled and the SFLAG/NFLAG input is ignored.
2–22
2.10 MUXOUT Output
MUXOUT is a TTL-compatible output. It is software programmable and controls external devices. Its typical
application is to select the HSYNC and VSYNC inputs between the VGA pass-through mode and the normal
modes. This output is driven low at power up or when the VGA pass-through mode is selected; at any other
time it can be programmed to the desired polarity through the general control register bit 7.
2.11 General Control Register
The general control register controls HSYNC and VSYNC polarity, split shift register transfer enabling,
special nibble mode, little-endian and big-endian modes, sync control, the ones-accumulation clock source,
and the VGA pass-through indicator. The bit field definitions are given in Table 2–11:
Table 2–11. General Control Register Bit Functions
GENERAL CONTROL REGISTER BIT
2.11.1
FUNCTION
7
6
5
4
3
2
1
0
X
X
X
X
X
X
X
0
HSYNCOUT is active-low
X
X
X
X
X
X
X
1
HSYNCOUT is active-high (default)
X
X
X
X
X
X
0
X
VSYNCOUT is active-low
X
X
X
X
X
X
1
X
VSYNCOUT is active-high (default)
X
X
X
X
X
0
X
X
Disable split shift register transfer (default)
X
X
X
X
0
1
X
X
Enable split shift register transfer
X
X
X
X
0
X
X
X
Disable special nibble mode (default)
X
X
X
X
1
0
X
X
Enable special nibble mode
X
X
X
0
X
X
X
X
0-IRE pedestal (default)
X
X
X
1
X
X
X
X
7.5-IRE pedestal
X
X
0
X
X
X
X
X
Disable sync (default)
X
X
1
X
X
X
X
X
Enable sync
X
0
X
X
X
X
X
X
Little-endian mode (default)
X
1
X
X
X
X
X
X
Big-endian mode
0
X
X
X
X
X
X
X
MUXOUT is low (default)
1
X
X
X
X
X
X
X
MUXOUT is high
HSYNCOUT and VSYNCOUT (Bits 0 and 1)
HSYNCOUT and VSYNCOUT polarity inversion is provided to allow indication to monitors of the current
screen resolution. Since the polarities for the VGA pass-through mode are provided at the feature connector,
the inputs to the TLC34076 already have right polarities for monitors, so the TLC34076 passes them through
with pipeline delay (see Section 2.8). These 2 bits work only in the normal modes, and the input horizontal
and vertical syncs are active-low incoming pulses. These 2 bits default to 1 but can be changed by software.
2.11.2
Split Shift Register Transfer Enable (SSRT) and Special Nibble Mode Enable
(SNM) (Bits 2 and 3)
Section 2.9 provides a detailed description for SSRT and SNM.
2.11.3
Pedestal Enable Control (Bit 4)
Bit 4 specifies whether a 0- or 7.5-IRE blanking pedestal is to be generated on the video outputs. Having
a 0-IRE blanking pedestal means that the Black and Blank levels are the same.
•
•
0 = 0-IRE pedestal (default)
1 = 7.5-IRE pedestal
2–23
2.11.4
Sync Enable Control (Bit 5)
Bit 5 specifies whether or not sync information is to be output onto IOG (see Table 2–11). Bit settings are:
•
0 = Disable sync (default)
•
1 = Enable sync
2.11.5
Little-Endian and Big-Endian Mode Control (Bit 6)
Bit 6 specifies either little-endain or big-endian data format for the pixel bus frame-buffer interface (see
subsection 2.7.1). Settings are :
•
0 = little endian (default)
•
1 = big endian
2.11.6
MUXOUT (Bit 7)
Bit 7 indicates to external circuitry that the device is running in VGA pass-through mode. The MUXOUT bit
does not affect the operation of the device (see Section 2.10). Bit settings are:
•
0 = MUXOUT is low (default in VGA pass-through mode)
•
1 = MUXOUT is high
2.12 Test Register
There are three test functions provided in the TLC34076, and they are all controlled and monitored through
the test register. The three test functions are:
•
Data flow check
•
DAC analog test
•
Screen integrity test
The test register has two ports: one for a control word that is accessed by writing to the register location,
and one for the data word that is accessed by reading from the register location. Depending on the channel
written in the control word, the data read presents the information for that channel.
The control word is 3 bits long and occupies D2 – D0 bit positions. It specifies which of the eight channels
to inspect. Table 2–12 and state machine diagrams (see Figure 2–11) show how each channel is addressed.
Table 2–12. Test Mode Selection
2–24
D2
D1
D0
0
0
0
Color palette red value
CHANNEL
0
0
1
Color palette green value
0
1
0
Color palette blue value
0
1
1
Identification code
1
0
0
Ones-accumulation red value
1
0
1
Ones-accumulation green value
1
1
0
Ones-accumulation blue value
1
1
1
Analog test
ID Code
011
RD
Red
000
RESET
RD
010
Blue
100
Blue
RD
110
Red
RD
RD
111
RD
001
DAC ANALOG TEST
RD
Green
DATA FLOW CHECK
RD
101
Green
SCREEN INTEGRITY TEST
Figure 2–11. Test-Register Control-Word State Diagrams
2.12.1
Frame-Buffer Data Flow Test
The TLC34076 provides a means to check all the data entering each DAC but before the output MUX 8/6
shift. When accessing these color channels, the data entering the DACs should be kept constant for the
entire MPU read cycle. This can be done either by slowing down the dot clock or ensuring that the data is
constant for a sufficiently long series of pixels. The value read is the data stored in the color palette location
addressed by the data in the input MUX. The read operation causes a post-increment to point to the next
color channel, and the post-increment of blue wraps back to red as shown in the state diagram of Figure
2–11. For example, when bits D2 – D0 are written as 001, then three successive reads are performed, and
the values read out are green, blue, and red in this sequence.
2.12.2
Identification (ID) Code
The ID code can be used as a software identification for different versions. The ID code in the TLC34076
is static and can be read without consideration of the dot clock or video signals. To be user-friendly, the read
post-increment applies to the ID register as well. However, when the state machine goes into the color
channel, it does not return to the ID code unless the user writes 011 (binary) to bits D2, D1, and D0 again.
If the test register was first written as 011 (binary) in bits D2, D1, and D0, then, when six successive reads
are performed, the first value read is the ID, and the last value read is the green.
The ID value defined for the TLC34076 is 76 (hex).
2.12.3
Ones-Accumulation Screen Integrity Test
A technique called ones accumulation can detect errors in fixed screen displays. This type of error detection
is useful for system checkout and field diagnostics.
Each of the 256 24-bit words in the TLC34076 internal color palette RAM is composed of three bytes, one
each for the red, green, and blue components of the word. When bits D2 – D0 are programmed with the
appropriate binary value (see subsection 2.12.4), the TLC34076 monitors the corresponding color byte that
is output by the color palette RAM. For example, when bits D2 – D0 are programmed with the value 100,
the TLC34076 monitors the red byte. As the current frame is scanned, for each color palette RAM word
accessed, the designated color byte is checked to see how many 1 bits it contains, and this number is added
to a temporary accumulator, the entire byte is checked, even when 6-bit mode is selected. For example,
when the designated color byte contains the value 41h (0100 0001), then the value 2 is added to the
temporary accumulator, as 41h contains two bits set at 1. This process is continued until an entire frame
has been scanned; the same color byte is monitored for the entire frame. The temporary accumulator
truncates any overflow above the value 255. Due to circuit speed limitations, the ones accumulation is
2–25
calculated at a speed of (DOTCLK frequency)/2. During the vertical retrace activated by a falling edge on
the TLC34076 VSYNC input, the value in the temporary accumulator is transferred into the ones
accumulation register, and then the temporary accumulator is reset to 0. The ones-accumulation register
is updated only on the falling edge of VSYNC, not by any vertical sync pulses coded into the composite video
signal. Before the next frame scan begins, the TLC34076 automatically changes the value in bits D2 – D0
so that the ones accumulation performed during the next frame scan is for a different color byte (see the
screen integrity test state diagram of Figure 2–11). As long as the screen display remains fixed, the
ones-accumulation value for a particular color byte should not change; when it does, an error has occurred.
Since ones accumulation is calculated at DOTCLK/2 rate, there is uncertainty as to whether it starts its
accumulation on an odd or even pixel. Regardless of whether the accumulation is performed on odd or even
pixels, subsequent screens are accumulated starting at the same point every time, unless the part is reset
or the DOTCLK source changes.
2.12.4
Analog Test
An analog test compares the voltage amplitudes of the analog red-green-blue (RGB) outputs to each other
and to a 145-mV reference. This enables the MPU to determine whether the CRT monitor is connected to
the analog RGB outputs or not and whether the DACs are functional. To perform an analog test, bits D2
– D0 must be set to 111; D7 – D4 bits are set as shown in Table 2–13. Bit D3 contains the result of the analog
test. The bit coding for the analog comparison of bits D2 – D7 is shown in Table 2–14.
Table 2–13. Test Register Bit Definitions for Analog Test
BIT DEFINITION
READ/WRITE
D7: Red select
Read/Write
D6: Green select
Read/Write
D5: Blue select
Read/Write
D4: 145-mV reference select
Read/Write
D3: Result
Read
Table 2–14. Bit Coding for Analog Comparisons of Bits D7 – D4
D7 – D4
OPERATION
IF D3 = 1
0000
Normal operation
Don’t care
Don’t care
1010
Red DAC compared to blue DAC
Red > blue
Red < blue
1001
Red DAC compared to 145-mV reference
Red > 145 mV
Red < 145 mV
0110
Green DAC compared to blue DAC
Green > blue
Green < blue
0101
Green DAC compared to 145-mV reference
Green > 145 mV
Green < 145 mV
NOTE 2: All the outputs have to be terminated to compare the voltage.
2–26
IF D3 = 0
Figure 2–12 is a schematic of the internal comparator circuitry for the analog comparison test.
IOR or IOG
+
IOB or 145 mV
–
D
Blank
(Internal Signal)
Q
D3
C
Figure 2–12. Internal Comparator Circuitry for Analog Test
The result of the analog comparison is strobed into bit D3 at the falling edge of an internal signal derived
from the input BLANK signal. In order to have stable inputs to the comparator, the DAC should be set to a
constant level between syncs. For normal operation, the data flow check, and the screen integrity test, bits
D7 – D4 must be set to 0.
2–27
2–28
3 Electrical Specifications
3.1
Absolute Maximum Ratings Over Operating Free-Air Temperature Range
(Unless Otherwise Noted)†
Supply voltage, VDD (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V
Input voltage range, VI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 0.5 V to VDD + 0.5 V
Analog output short-circuit duration to any power supply or common . . . . . . . . unlimited
Operating free-air temperature range, TA: TLC34076C . . . . . . . . . . . . . . . . . 0°C to 70°C
TLC34076M . . . . . . . . . . . . . –55°C to 125°C
Storage temperature range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 65°C to 150°C
Junction temperature, TJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175°C
Case temperature for 10 seconds TC: FN and GA package . . . . . . . . . . . . . . . . . . . 260°C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds . . . . . . . . . . . . . . 260°C
† Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These
are stress ratings only and functional operation of the device at these or any other conditions beyond those indicated
under “recommended operating conditions” is not implied. Exposure to absolute-maximum-rated conditions for
extended periods may affect device reliability.
NOTE 1: All voltage values are with respect to the GND terminal.
3.2
Recommended Operating Conditions
MIN
NOM
MAX
UNIT
VDD
VREF
Supply voltage
4.75
5
5.25
V
Reference voltage
1.15
1.235
1.26
V
VIH
VIL
High-level input voltage
TTL inputs
2.4
V
Low-level input voltage
TTL inputs
VDD+0.5
0.8
VID
VIC
Differential input voltage
ECL inputs
0.6
6
V
Common-mode input voltage
ECL inputs
2.85
RL
Output load resistance
37.5
Ω
RSET
FS ADJUST resistor
523
Ω
TA
Operating free-air
free air temperature
3.15
VDD – 0.5
TLC34076C
0
70
TLC34076M
–55
125
V
V
°C
3–1
3.3
3.3.1
Electrical Characteristics
Electrical Characteristics for TLC34076C Over Operating Free-Air Temperature
Range
PARAMETER
VOH
VOL
TEST CONDITIONS
IOH = –800 µA
High-level output voltage
L
Low-level
l
l output
t t voltage
lt
High level input current
High-level
IIL
Low level input current
Low-level
TYP†
IOL = 3.2 mA
0.4
HSYNCOUT,
VSYNCOUT
IOL = 15 mA
0.4
IOL = 18 mA
VI = 2.4 V
0.4
TTL inputs
ECL inputs
V
1
TTL inputs
VI = 4 V
VI = 0.8 V
–1
ECL inputs
VI = 0.4 V
–1
IDD
Supplyy
current
True-color
mode
TLC34076-110
TLC34076-135
1
535
TLC34076-85
475
High-impedance-state output current
Ci
Input capacitance
mA
475
VDD = 5 V,,
See Note 2
475
TLC34076-170
IOZ
µA
475
VDD = 5 V,,
See Note 2
525
TLC34076-135
µA
450
TLC34076-170
TLC34076-110
UNIT
V
TLC34076-85
Pseudo-color
mode
MAX
2.4
D0 – D7,
MUXOUT,
VCLK
SCLK
IIH
MIN
475
10
TTL inputs
f = 1 MHz, VI = 2.4 V
4
ECL inputs
f = 1 MHz, VI = 4 V
4
µA
pF
† All typical values are at VDD = 5 V, TA = 25°C.
NOTE 2: IDD is measured with the dot clock running at the maximum specified frequency, SCLK frequency =
DOTCLK frequency/4, and the palette RAM loaded with full-range toggling patterns (00h/00h/FFh/FFh/00h/
00h/FFh/FFh/ . . .). Pseudo-color mode is also known as color indexing mode.
3–2
3.3.2
Electrical Characteristics for TLC34076M Over Operating Free-Air Temperature
Range
PARAMETERS
VOH
VOL
IIH
IIL
IDD
IOZ
Ci
TEST CONDITIONS
IOH = – 800 µA,
VDD = 4.75 V
High-level output voltage
Low-level output voltage
2.4
0.4
HSYNCOUT,
VSYNCOUT
IOL = 15 mA,
VDD = 4.75 V
0.4
SCLK
IOL = 18 mA,
VDD = 4.75 V
0.4
TTL inputs
VI = 2.4 V,
VDD = 5.25 V
10
ECL inputs
VI = 4 V,
VDD = 5.25 V
10
TTL inputs
VI = 0.8 V,
VDD = 5.25 V
– 10
ECL inputs
VI = 0.8 V,
VDD = 5.25 V
– 10
Pseudo-color
mode
TLC34076M-135
True-color
mode
TLC34076M-135
High-impedance-state output current
VDD = 5.25 V
f = 1 MHz, VI = 2.4 V
ECL inputs
f = 1 MHz, VI = 4 V
V
µA
µA
535
VDD = 5 V,,
See Note 2
TTL inputs
UNIT
V
IOL = 3.2 mA,
VDD = 4.75 V
Low level input current
Low-level
Input capacitance
MAX
D0 – D7,
MUXOUT,
VCLK
High level input current
High-level
Supplyy
current
MIN TYP†
mA
475
10
4
4
25
µA
pF
† All typical values are at VDD = 5 V, TA = 25°C.
NOTE 2: IDD is measured with the dot clock running at the maximum specified frequency, SCLK frequency =
DOTCLK frequency/4, and the palette RAM loaded with full-range toggling patterns (00h/00h/FFh/FFh/00h/
00h/FFh/FFh/ . . .). Pseudo-color mode is also known as color-indexing mode.
3–3
3.4
Operating Characteristics
The following tables outline the operating characteristics for the TLC34076C and TLC34076M.
3.4.1
Operating Characteristics for TLC34076C Over Recommended Ranges of
Supply Voltage and Operating Free-Air Temperature
PARAMETER
Resolution (each DAC)
EL
End-point linearity
y error
(each DAC)
ED
Differential linearity
error
(each DAC)
TEST CONDITIONS
MIN
TYP
8/6 high
8
8/6 low
6
8/6 high
1/4
8/6 high
LSB
1
LSB
8/6 low
1/4
5%
White level relative to Blank
17.69
19.05
20.4
White level relative to Black (7.5 IRE only)
16.74
17.62
18.5
Black level relative to Blank (7.5 IRE only)
0.95
1.44
1.9
mA
0
5
50
µA
Blank level on IOG (with Sync enabled)
6.29
7.6
8.96
mA
Sync level on IOG (with Sync enabled)
0
5
50
µA
Blank level on IOR, IOB
One LSB (8/6 high)
69.1
One LSB (8/6 low)
276.4
DAC-to-DAC matching outputs
2%
DAC-to-DAC crosstalk
µA
5%
–20
Voc
VREF
Output compliance voltage
ZO
CO
Output impedance
Voltage reference output voltage
Output capacitance
UNIT
bits
1
8/6 low
Gray-scale error
Output current
(see Note 4)
MAX
f = 1 MHz, IOUT = 0
–1
1.15
dB
1.2
1.235
1.26
V
V
50
kΩ
13
pF
Clock and data feedthrough
–20
dB
Glitch impulse (see Note 3)
50
pV-s
Normal mode
VGA pass-through mode
1 SCLK + 9 DOTCLK
7.5 DOTCLK
NOTES: 3. Glitch impulse does not include clock and data feedthrough. The – 3-dB test bandwidth is twice the clock
rate.
4. Unless otherwise specified, test conditions for RS343-A video signals are those listed in the
Recommended Operating Conditions, using external voltage reference VREF = 1.235 V and RSET = 523
Ω. When using the internal voltage reference, RSET may need to be adjusted to meet these limits.
3–4
3.4.2
Operating Characteristics for TLC34076M Over Recommended Ranges of
Supply Voltage and Operating Free-Air Temperature
PARAMETER
Resolution (each DAC)
TEST CONDITIONS
MIN
TYP†
8/6 high
8
8/6 low
6
8/6 high
EL
End-point linearity
y error
(each DAC)
8/6 low
ED
Differential linearityy error
(each DAC)
8/6 low
1/4
8/6 high
Output current
(see Note 4)
1
1/4
ZO
CO
Output impedance
5%
19.05
20.4
White level relative to Black (7.5 IRE only)
16.74
17.62
18.5
Black level relative to Blank (7.5 IRE only)
0.95
1.44
1.9
Blank level on IOR, IOB
– 50
5
50
µA
Blank level on IOG (with Sync enabled)
6.29
7.6
8.96
mA
Sync level on IOG (with Sync enabled)
– 50
5
50
µA
One LSB (8/6 high)
69.1
One LSB (8/6 low)
276.4
2%
– 0.4
1.1
5%
dB
1.2
V
1.3
V
50
f = 1 MHz,
IO = 0
Clock and data feedthrough
Glitch impulse (see Note 3)
Pipeline delay
1.235
Normal mode
VGA pass-through mode
mA
µA
– 20
Voltage reference output voltage
Output capacitance
LSB
17.69
DAC-to-DAC crosstalk
Output compliance voltage
LSB
White level relative to Blank
DAC-to-DAC matching outputs
Voc
VREF
UNIT
bits
1
Gray-scale error
IO
MAX
kΩ
13
pF
–20
dB
50
pV-s
1 SCLK + 9 dot clock
7.5 dot clock
periods
† All typical values are at VDD = 5 V, TA = 25°C.
NOTES: 3. Glitch impulse does not include clock and data feedthrough. The – 3-dB test bandwidth is twice the clock
rate.
4. Unless otherwise specified, test conditions for RS343-A video signals are those listed in the
Recommended Operating Conditions, using external voltage reference VREF = 1.235 V and RSET = 523Ω.
When using the internal voltage reference, RSET may need to be adjusted to meet these limits.
3–5
3.5
Timing Requirements
The following tables outline the timing requirements for the TLC34076C and TLC34076M.
3.5.1
Timing Requirements for TLC34076C Over Recommended Ranges of Supply
Voltages and Operating Temperature (see Note 5)
-85
MIN
DOTCLK frequency
-110
MAX
MIN
85
CLK0 frequency for VGA pass-through mode
85
TTL
11.8
9.1
ECL
11.8
9.1
MAX
UNIT
110
MHz
85
MHz
tcyc
Cycle time,
time CLK0 – CLK3 (see Figure 3–2)
3 2)
tsu1
Setup time, RS0 – RS3 valid before RD or WR↓
(see Figure 3–1)
10
10
ns
th1
Hold time, RS0 – RS3 valid after RD or WR low (see Figure
3–1)
10
10
ns
Setup time, D0 – D7 valid before WR↑ (see Figure 3–1)
35
35
ns
Hold time, D0 – D7 valid after WR high (see Figure 3–1)
0
0
ns
tsu3
Setup time, VGA0 – VGA7 and HSYNC, VSYNC, and
VGABLANK valid before CLK0-CLK3↑ (see Figure 3–2)
2
2
ns
th3
Hold time, VGA0 – VGA7 and HSYNC, VSYNC, and
VGABLANK valid after CLK0 high (see Figure 3–2)
2
2
ns
Setup time, P0 – P31 valid before SCLK↑ (see Figure 3–2)
2
2
ns
Hold time, P0 – P31 valid after SCLK high (see Figure 3–2)
5
5
ns
tsu5
Setup time, HSYNC, VSYNC, and BLANK valid before VCLK
low (see Figure 3–2)
5
5
ns
th5
Hold time, HSYNC, VSYNC, and BLANK valid after VCLK↓
(see Figure 3–2)
2
2
ns
50
50
ns
ns
tsu2
th2
tsu4
th4
tw1
tw2
Pulse duration, RD or WR low (see Figure 3–1)
Pulse duration, RD or WR high (see Figure 3–1)
tw3
3
Pulse duration,
duration CLK0–CLK3
CLK0 CLK3 high (see Figure 3–2)
3 2)
tw4
4
Pulse duration,
duration CLK0–CLK3
CLK0 CLK3 low (see Figure 3–2)
3 2)
tw5
Pulse duration, SFLAG/NFLAG high (see Note 6 and
Figure 3–3)
30
30
TTL
4
3.5
ECL
4
3.5
TTL
4
3.5
ECL
4
3.5
30
30
ns
ns
ns
ns
NOTES: 5. TTL input signals are 0 to 3 V with less than 3 ns rise/fall time between the 10% and 90% levels, unless
otherwise specified. ECL input signals are VDD –1.8 V to VDD – 0.8 V with less than 2 ns rise/fall time
between the 20% and 80% levels. For input and output signals, timing reference points are at the 10% and
90% signal levels. Analog output loads are less than 10 pF. D0 – D7 output loads are less than 50 pF. All
other output loads are less than 50 pF, unless otherwise specified.
6. This parameter applies when the split shift–register transfer (SSRT) function is enabled (see subsection
2.9.1 for details).
3–6
3.5.1
Timing Requirements for TLC34076C Over Recommended Ranges of Supply
Voltages and Operating Temperature (see Note 5) (Continued)
-135
MIN
DOTCLK frequency
CLK0 frequency for VGA pass-through mode
-170
MAX
MIN
MAX
UNIT
135
170
MHz
85
85
MHz
TTL
7.4
7.4
ECL
7.4
5.8
Setup time, RS0 – RS3 valid before RD or WR↓
(see Figure 3–1)
10
10
ns
Hold time, RS0 – RS3 valid after RD or WR low (see Figure
3–1)
10
10
ns
Setup time, D0 – D7 valid before WR↑ (see Figure 3–1)
35
35
ns
Hold time, D0 – D7 valid after WR high (see Figure 3–1)
0
0
ns
tsu3
Setup time, VGA0 – VGA7, HSYNC, VSYNC, and VGABLANK
valid before CLK0↑ (see Figure 3–2)
2
2
ns
th3
Hold time, VGA0 – VGA7, HSYNC, VSYNC, and VGABLANK
valid after CLK0 high (see Figure 3–2)
2
2
ns
Setup time, P0 – P31 valid before SCLK↑ (see Figure 3–2)
0
0
ns
Hold time, P0 – P31 valid after SCLK high (see Figure 3–2)
5
5
ns
tsu5
Setup time, HSYNC, VSYNC, and BLANK valid before VCLK
low (see Figure 3–2)
5
5
ns
th5
Hold time, HSYNC, VSYNC, and BLANK valid after VCLK low
(see Figure 3–2)
2
2
ns
tcyc
Clock cycle time,
time CLK0-CLK3
CLK0 CLK3 (see Figure 3–2)
3 2)
tsu1
th1
tsu2
th2
tsu4
th4
ns
tw1
tw2
Pulse duration, RD or WR low (see Figure 3–1)
50
50
ns
Pulse duration, RD or WR high (see Figure 3–1)
30
30
ns
tw3
3
Pulse duration,
duration CLK0 –CLK3
CLK3 high (see Figure 3–2)
3 2)
tw4
4
Pulse duration,
duration CLK0 –CLK3
CLK3 low (see Figure 3–2)
3 2)
tw5
Pulse duration, SFLAG/NFLAG high (see Note 6 and
Figure 3–3)
TTL
3
3
ECL
3
2.5
TTL
3
3
ECL
3
2.5
30
30
ns
ns
ns
NOTES: 5. TTL input signals are 0 to 3 V with less than 3 ns rise/fall time between the 10% and 90% levels, unless
otherwise specified. ECL input signals are VDD –1.8 V to VDD – 0.8 V with less than 2 ns rise/fall time
between the 20% and 80% levels. For input and output signals, timing reference points are at the 10% and
90% signal levels. Analog output loads are less than 10 pF. D0 – D7 output loads are less than 50 pF. All
other output loads are less than 50 pF, unless otherwise specified.
6. This parameter applies when the split shift-register transfer (SSRT) function is enabled (see subsection
2.9.1 for details).
3–7
3.5.2
Timing Requirements for TLC34076M Over Recommended Ranges of Supply
Voltages and Operating Temperature (see Note 5)
MIN
NOM
Dot-clock frequency
CLK0 frequency for VGA pass-through mode
TTL
7.4
ECL
7.4
MAX
UNIT
135
MHz
85
MHz
tc
Cycle time
time, CLK0 – CLK3 (see Figure 3–2)
3 2)
tsu1
th1
Setup time, RS0 – RS3 valid before RD or WR↓ (see Figure 3–1)
10
ns
Hold time, RS0 – RS3 valid after RD or WR low (see Figure 3–1)
10
ns
tsu2
th2
Setup time, D0 – D7 valid before WR↑ (see Figure 3–1)
35
ns
Hold time, D0 – D7 valid after WR high (see Figure 3–1)
0
ns
tsu3
Setup time, VGA0 – VGA7 and HSYNC, VSYNC, and VGABLANK valid
before CLK0-CLK3↑ (see Figure 3–2)
2
ns
th3
Hold time, VGA0 – VGA7 and HSYNC, VSYNC, and VGABLANK valid
after CLK0 high (see Figure 3–2)
2
ns
Setup time, P0 – P31 valid before SCLK↑ (see Figure 3–2)
0
ns
Hold time, P0 – P31 valid after SCLK high (see Figure 3–2)
8
ns
tsu5
Setup time, HSYNC, VSYNC, and BLANK valid before VCLK↓ (see
Figure 3–2)
5
ns
th5
Hold time, HSYNC, VSYNC, and BLANK valid after VCLK low (see
Figure 3–2)
2
ns
tsu4
th4
ns
tw1
tw2
Pulse duration, RD or WR low (see Figure 3–1)
50
ns
Pulse duration, RD or WR high (see Figure 3–1)
30
ns
tw3
3
duration CLK0 – CLK3 high (see Figure 3–2)
3 2)
Pulse duration,
tw4
4
Pulse duration,
duration CLK0 – CLK3 low (see Figure 3–2)
3 2)
TTL
3
ECL
3
TTL
3
ECL
3
ns
ns
tw5
Pulse duration, SFLAG/NFLAG high (see Note 6 and Figure 3–3)
30
ns
† All typical values are at VDD = 5 V, TA = 25°C.
NOTES: 5. TTL input signals are 0 to 3 V with less than 3 ns rise/fall time between the 10% and 90% levels, unless
otherwise specified. ECL input signals are VDD –1.8 V to VDD – 0.8 V with less than 2 ns rise/fall time
between the 20% and 80% levels. For input and output signals, timing reference points are at the 10% and
90% signal levels. Analog output loads are less than 10 pF. D0 – D7 output loads are less than 50 pF. All
other output loads are less than 50 pF, unless otherwise specified.
6. This parameter applies when the split shift register transfer (SSRT) function is enabled (see subsection
2.9.1 for details).
3–8
3.6
Switching Characteristics for TLC34076C and TLC34076M Over
Recommended Ranges of Supply Voltages and Operating Temperature
PARAMETER
MIN
-85
TYP†
MAX
MIN
-110
TYP†
MAX
UNIT
SCLK frequency (see Note 7)
85
85
MHz
VCLK frequency
85
85
MHz
ten
Enable time, RD low to D0 – D7 valid (see
Figure 3–1)
40
40
ns
tdis
Disable time, RD high to D0 – D7 disabled (see
Figure 3–1)
17
17
ns
tv
Valid time, D0 – D7 valid after RD high (see
Figure 3–1)
5
tPLH
Propagation delay, SFLAG/NFLAG high to SCLK↑
(see Note 8 and Figure 3–3)
0
td1
Delay time, RD low to D0 – D7 starting to turn on
(see Figure 3–1)
5
td2
Delay time, selected input clock high/low to
DOTCLK (internal signal) high/low (see Figure 3–2)
7
7
ns
td3
Delay time, DOTCLK high/low to VCLK high/low
(see Figure 3–2)
6
6
ns
td4
Delay time, VCLK high/low to SCLK high/low (see
Note 9 and Figure 3–2)
td5
Delay time, DOTCLK high/low to SCLK high/low
(see Figure 3–2)
8
8
ns
td6
Delay time, DOTCLK high to IOR/IOG/IOB active
(analog output delay time) (see Note 10 and
Figure 3–2)
20
20
ns
td7
Analog output settling time (see Note 11 and
Figure 3–2)
td8
Delay time, DOTCLK high to HSYNCOUT and
VSYNCOUT valid (see Figure 3–2)
tw6
Pulse duration, SCLK high (see Note 12 and
Figure 3–3)
tr
Rise time at HSYNCOUT analog output
(see Note 13 and Figure 3–2)
5
20
ns
0
20
5
0
5
ns
0
5
8
6
5
15
3
55
2
ns
15
ns
ns
55
2
ns
ns
ns
Analog output skew
0
2
0
2
ns
† All typical values are at VDD = 5 V, TA = 25°C.
NOTES: 7. SCLK can drive an output capacitive load up to 60 pF with worst-case transition time between the 10% and
90% levels less than 4 ns (typical 3 ns). SCLK can drive output capacitive loads up to 120 pF, with typical
transition time (10% to 90%) of 4 ns.
8. This parameter applies when the split shift-register transfer (SSRT) function is enabled (see subsection
2.9.1 for details).
9. VCLK frequency = SCLK frequency.
10. Measured from the 90% point of the rising edge of DOTCLK to 50% of the full-scale transition.
11. Measured from the 50% point of the full-scale transition to the point at which the output has settled, within
± 1 LSB (settling time does not include clock and data feedthrough).
12. SCLK can be programmed to latch pixel data at the input port up to this limit. However, the SCLK output
buffer can only be used up to the SCLK frequency limit of 85 MHz.
13. Measured between 10% and 90% of the full-scale transition.
3–9
3.6
Switching Characteristics (TLC34076C and TLC34076M) Over
Recommended Ranges of Supply Voltages and Operating Temperature
(Continued)
PARAMETER
MIN
-135
TYP†
MAX
MIN
-170
TYP†
MAX
UNIT
SCLK frequency (see Note 7)
85
85
MHz
VCLK frequency
85
85
MHz
ten
Enable time, RD low to D0 – D7 valid (see
Figure 3–1)
40
40
ns
tdis
Disable time, RD high to D0 – D7 disabled (see
Figure 3–1)
17
17
ns
tv
Valid time, D0 – D7 valid after RD high (see
Figure 3–1)
5
tPLH
Propagation delay, SFLAG/NFLAG high to SCLK ↑
(see Note 8 and Figure 3–3)
0
td1
Delay time, RD low to D0 – D7 valid (see
Figure 3–1)
5
td2
Delay time, selected input clock high/low to DOTCLK
(internal signal) high/low (see Figure 3–2)
7
7
ns
td3
Delay time, DOTCLK high/low to VCLK high/low (see
Figure 3–2)
6
6
ns
td4
Delay time, VCLK high/low to SCLK high/low
(see Note 9 and Figure 3–2)
td5
Delay time, DOTCLK high/low to SCLK high/low (see
Figure 3–2)
5
20
ns
0
20
5
0
5
8
ns
ns
0
8
5
ns
5
ns
† All typical values are at VDD = 5 V, TA = 25°C.
NOTES: 7. SCLK can drive output capacitive loads up to 60 pF, with worst case transition time between 10% and 90%
levels less than 4 ns (typical 3 ns). SCLK can drive output capacitive loads up to 120 pF, with typical
transition time (10% to 90%) of 4 ns.
8. This parameter applies when the split shift-register transfer (SSRT) function is enabled (see subsection
2.9.1 for details).
9. VCLK frequency = SCLK frequency.
10. Measured from the 90% point of the rising edge of DOTCLK to 50% of the full-scale transition.
11. Measured from the 50% point of the full-scale transition to the point at which the output has settled, within
± 1 LSB (settling time does not include clock and data feedthrough).
12. SCLK can be programmed to latch pixel data at the input port up to this limit. However, the SCLK output
buffer can only be used up to the SCLK frequency limit of 85 MHz.
13. Measured between 10% and 90% of the full-scale transition.
3–10
3.6
Switching Characteristics (TLC34076C and TLC34076M) Over
Recommended Ranges of Supply Voltages and Operating Temperature
(Continued)
PARAMETER
td6
Delay time, DOTCLK high to IOR/IOG/IOB active
(analog output delay time) (see Note 10 and
Figure 3–2)
td7
Analog output settling time (see Note 11 and Figure
3–2)
td8
Delay time, DOTCLK high to HSYNCOUT and
VSYNCOUT valid (see Figure 3–2)
tw6
Pulse duration, SCLK high (see Note 8 and
Figure 3–3)
MIN
-135
TYP†
MAX
MIN
20
6
3
15
-170
TYP†
ns
5
ns
3
ns
55
ns
110
Rise time at HSYNCOUT Analog output
(see Note 13 and Figure 3–2)
Analog output skew
2
0
2
2
UNIT
20
Pixel data latching frequency (see Note 12)
tr
MAX
0
MHz
ns
2
ns
† All typical values are at VDD = 5 V, TA = 25°C.
8. This parameter applies when the split shift-register transfer (SSRT) function is enabled (see subsection
2.9.1 for details).
10. Measured from the 90% point of the rising edge of DOTCLK to 50% of the full-scale transition.
11. Measured from the 50% point of the full-scale transition to the point at which the output has settled, within
± 1 LSB (settling time does not include clock and data feedthrough).
12. SCLK can be programmed to latch pixel data at the input port up to this limit. However, the SCLK output
buffer can only be used up to the SCLK frequency limit of 85 MHz.
13. Measured between 10% and 90% of the full-scale transition.
3–11
3.7
Timing Diagrams
tsu1
RS0 – RS3
th1
Valid
tw1
tw2
RD,WR
tdis
ten
D0 – D7
(Output)
Data Out, RD Low
ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ
ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ
td1
D0 – D7
(Input)
tsu2
Figure 3–1. MPU Interface Timing
3–12
ÎÎÎÎÎ
ÎÎÎÎÎ
tv
Data In,
WR Low
th2
tcyc
tw3
tw4
CLK0 – CLK3
td2
td2
DOTCLK
(Internal Signal)
td3
td3
VCLK
td4
td5
td4
td5
SCLK
th3
tsu3
VGA0 – VGA7,
HSYNC, VSYNC, VGABLANK
(VGA Pass-Through Mode)
Data
th4
tsu4
ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ
ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ
ÎÎÎÎÎÎÎÎÎÎÎÎÎÎ
ÎÎÎÎÎÎÎÎÎÎÎÎÎÎ
ÎÎÎÎÎÎÎÎÎÎÎÎ
ÎÎÎÎÎÎÎÎÎÎÎÎ
Data
P0 – P31
th5
tsu5
HSYNC, VSYNC, BLANK
(Normal Mode)
Data
td6
td7
IOR,IOG,IOB
td8
HSYNCOUT
VSYNCOUT
Valid
tr
Valid
Figure 3–2. Video Input/Output Timing
BLANK
tw5
SFLAG/
NFLAG
tPLH
tw6
SCLK
Figure 3–3. SFLAG/NFLAG Timing (When SSRT Function is Enabled)
3–13
3–14
Appendix A
SCLK/VCLK and the TMS340x0
While the TLC34076 SCLK and VCLK outputs are designed for compatibility with all graphics systems, they
are also tightly coupled with the TMS340x0 graphics system processors. All the timing requirements of the
TMS340x0 have been considered. However, there are a few points that need to be explained with regard
to applications.
VCLK
All the video control signals in the TMS340x0 (i.e., BLANK, HSYNC, and VSYNC) are triggered and
generated from the falling edge of VCLK. The fact that the TLC34076 uses the falling edge to sample and
latch the BLANK input gives users maximum freedom to choose the frequency of VCLK and interconnect
the TLC34076 with the TMS340x0 GSP without glue logic. Needless to say, the VCLK frequency needs to
be selected to be compatible with the minimum VCLK period required by the TMS340x0.
In the TMS340x0, the same VCLK falling edge that generates BLANK requests a screen refresh. When the
VCLK period is longer than 16 TQs (TQ is the period of the TMS340x0 CLKIN), it is possible that the last
SCLK pulse could be used falsely to transfer the VRAM data from memory to the shift register along with
the last pixel transfer. The first SCLK pulse for the next scan line would then shift the first pixel data out of
the pipe and the screen would then falsely start from the second pixel.
SCLK and SFLAG
The TLC34076 SCLK signal is compatible with current 10 ns and slower VRAMs. When split-shift register
transfers are used, one SCLK pulse has to be generated between the regular shift register transfer and the
split-shift register transfer to ensure correct operation. The SFLAG input is designed for this purpose.
SFLAG can be generated from a programmable logic array and triggered by the rising edge of the TR/QE
signal or the rising edge of the RAS signal of the regular shift register transfer cycle. TR/QE can be used
if the minimum delay from when the VRAM TRG signal goes high to SCLK going high can be met by the
programmable logic array delay; otherwise, RAS can be used.
A–1
A–2
Appendix B
Printed Circuit Board Layout Considerations
Printed Circuit Board (PCB) Considerations
A four-layer printed-circuit board (PCB) should be used with the TLC34076, one layer each for 5-V power
and GND and two layers for signals. The layout should be optimized for the lowest possible noise on the
TLC34076 power and ground lines by shielding the digital inputs and providing good decoupling. The lead
length between groups of VDD and GND terminals should be minimized so as to reduce inductive ringing.
The terminal assignments for the TLC34076 P0 – P31 inputs were selected for minimum interconnect
lengths between these inputs and the VRAM pixel data outputs. The TLC34076 should be located as close
to the output connectors as possible to minimize noise pickup and reflections due to impedance
mismatching.
Ground Plane
A single ground plane is recommended for both the TLC34076 and the rest of the logic. Separate digital and
analog ground planes are not needed.
Power Plane
Split power planes are recommended for the TLC34076 and the rest of the logic. The TLC34076 and its
associated analog circuitry should have their own power plane, referred to as AVCC in Figure B –1. The two
power planes should be connected at a single point through a ferrite bead as shown in Figures B –1, B –2,
and B –3. This bead should be located within 3 inches of the TLC34076.
Supply Decoupling
Bypass capacitors should be installed using the shortest leads possible, being consistent with reliable
operation to reduce the lead inductance.
For the best performance, a 0.1-µF ceramic capacitor in parallel with a 0.01-µF chip capacitor should be
used to decouple each of the three groups of power terminals to GND. These capacitors should be placed
as close as possible to the device as shown in Figure B –2.
When a switching power supply is used, the designer should pay close attention to reducing power supply
noise and should consider using a 3-terminal voltage regulator for supplying power to AVCC.
COMP and VREF Terminals
A 100-Ω resistor (optional) and 0.1-µF ceramic capacitor (approximate values) should be connected in
series between the device COMP and VDD terminals in order to avoid noise and color-smearing problems.
Also, whether an internal or external voltage reference is used, a 0.1-µF capacitor should be connected
between the device VREF and GND terminals to further stabilize the video image. The resistor and capacitor
values may vary depending on the board layout; experimentation may be required in order to determine
optimum values.
B–1
R6
COMP
C9
L1
AVCC
VDD
VCC
R1
C1-C3
C5-C7
C11
VREF
C12
TLC34076
C10
D1
GND
GND
R2
R3
R4
R5
FS ADJUST
IOR
To Video Connector
IOG
IOB
LOCATION
DESCRIPTION
C1-C3, C9-C10, C12
0.1-µF ceramic capacitor
C5-C7
0.01-µF ceramic chip capacitor
C11
33-µF tantalum capacitor
L1
ferrite bead
R1
1000-Ω 1% metal-film resistor
R2
523-Ω 1% metal-film resistor
R3, R4, R5
75-Ω 1% metal-film resistor
R6
100-Ω 5% resistor
D1
1.2-V voltage reference
Figure B–1. Typical Connection Diagram and Components (Shaded Area is Optional)
B–2
R1
C7
D1
C3
R6
P1
R3
R4
TLC34076
C5, C8
U1
+
C2
C6
L1
DB15 or
DB9 Connecator
C9
C12
C1
C4
C10
R2
R5
C11
Edge of
the Board
Figure B –2. Typical Component Placement (Component Side)
VCC
AVCC
Edge of
the Board
VCC
VCC
Figure B– 3. Typical Split Power Plane (Solder Side)
B–3
B–4
Appendix C
SCLK Frequency < VCLK Frequency
The VCLK and SCLK outputs generated by the TLC34076 are both free-running clocks. The video control
signals (i.e., HSYNC, VSYNC, and BLANK) are normally generated from VCLK, and a fixed relationship
between the video control signals and VCLK can, therefore, be expected. The TLC34076 samples and
latches the BLANK input on the falling edge of VCLK. It then looks at the Load signal to determine when
to disable or enable SCLK at its output terminal. The decision is deterministic when the SCLK frequency
is greater than or equal to the VCLK frequency. However, when the SCLK frequency is less than the VCLK
frequency, the appearance of the SCLK waveform at its output terminal when BLANK is sampled low on the
VCLK falling edge can vary (see Figures C –1 and C – 2).
To avoid this variation in the SCLK output waveform, the SCLK and VCLK frequencies should be chosen
so that HTOTAL is evenly divisible by the ratio of VCLK frequency:SCLK frequency; that is:
remainder of
ȱȧ
Ȳǒ
HTOTAL
VCLK frequency
SCLK frequency
ȳȧ +
Ǔȴ
0
For example, if HTOTAL is even, VCLK frequency = DOTCLK frequency/8, and SCLK frequency =
DOTCLK frequency/16, then the formula above is satisfied.
ȱȧ
Ȳǒ
ȳȧ
Ǔȴ
NOTE: When HTOTAL starts at zero (as in the TMS340x0 GSP), then the formula becomes:
remainder of
) 1) + 0
VCLK frequency
(HTOTAL
SCLK frequency
VCLK
BLANK
Load
(Internal Signal
for Data Latch)
SCLK at
Output Terminal
Figure C –1. VCLK and SCLK Phase Relationship (Case 1)
C–1
VCLK
BLANK
Load
(Internal Signal
for Data Latch)
SCLK at
Output Terminal
Figure C – 2. VCLK and SCLK Phase Relationship (Case 2)
C–2
Appendix D
Mechanical Data
FN (S-PQCC-J**)
PLASTIC QUAD CHIP CARRIER
20 PIN SHOWN
Seating Plane
0.004 (0,10)
0.180 (4,57) MAX
D
0.120 (3,05)
0.090 (2,29)
D1
0.020 (0,51) MIN
3
1
19
0.032 (0,81)
0.026 (0,66)
18
4
E
D2 / E2
E1
D2 / E2
14
8
0.021 (0,53)
0.013 (0,33)
0.007 (0,18) M
0.050 (1,27)
9
13
0.008 (0,20) NOM
D/E
D2 / E2
D1 / E1
NO. OF
PINS
**
MIN
MAX
MIN
MAX
MIN
MAX
20
0.385 (9,78)
0.395 (10,03)
0.350 (8,89)
0.356 (9,04)
0.141 (3,58)
0.169 (4,29)
28
0.485 (12,32)
0.495 (12,57)
0.450 (11,43)
0.456 (11,58)
0.191 (4,85)
0.219 (5,56)
44
0.685 (17,40)
0.695 (17,65)
0.650 (16,51)
0.656 (16,66)
0.291 (7,39)
0.319 (8,10)
52
0.785 (19,94)
0.795 (20,19)
0.750 (19,05)
0.756 (19,20)
0.341 (8,66)
0.369 (9,37)
68
0.985 (25,02)
0.995 (25,27)
0.950 (24,13)
0.958 (24,33)
0.441 (11,20)
0.469 (11,91)
84
1.185 (30,10)
1.195 (30,35)
1.150 (29,21)
1.158 (29,41)
0.541 (13,74)
0.569 (14,45)
4040005 / B 03/95
NOTES: A. All linear dimensions are in inches (millimeters).
B. This drawing is subject to change without notice.
C. Falls within JEDEC MS-018
D–1
Mechanical Data (continued)
GA-GB (S-CPGA-P12 X 12)
CERAMIC PIN GRID ARRAY PACKAGE
A or A1 SQ
1.100 (27,94) TYP
M
L
K
J
H
G
F
E
D
C
B
A
1
DIM
B or B1
2
3
4
5
6
7
8
9
10 11 12
MIN
MAX
Notes
A
1.240 (31,50)
1.280 (32,51)
Large
Outline
A1
1.180 (29,97)
1.235 (31,37)
Small
Outline
B
0.110 (2,79)
0.205 (5,21)
Cavity
Up
B1
0.095 (2,41)
0.205 (5,21)
Cavity
Down
C
0.040 (1,02)
0.060 (1,52)
Cavity
Up
C1
0.025 (0,63)
0.060 (1,52)
Cavity
Down
C or C1
0.050 (1,27) DIA
4 Places
0.022 (0,55)
DIA TYP
0.016 (0,41)
0.140 (3,56)
0.120 (3,05)
0.100 (2,54)
MAXIMUM PINS WITHIN MATRIX – 144
4040114-5 / B 10/94
NOTES: A.
B.
C.
D.
All linear dimensions are in inches (millimeters).
This drawing is subject to change without notice.
Index mark may appear on top or bottom depending on package vendor.
Pins are located within 0.005 (0,13) radius of true position relative to each other at maximum material
condition and within 0.015 (0,38) radius relative to the center of the ceramic.
E. This package can be hermetically sealed with metal lids or with ceramic lids using glass frit.
F. The pins can be gold-plated or solder-dipped.
G. Falls within MIL-STD-1835 CMGA4-PN and CMGA16-PN and JEDEC MO-067AD and MO-066AD,
respectively
D–2