Vmar DEHAVILAND DHC-2 BEAVER Supplement

OC65548
VGA BIOS
OEM Reference Guide
Revision 1.1
October 1995

Confidential Information

Copyright Notice
Copyright1995 Chips and Technologies, Inc. ALL RIGHTS RESERVED.
This manual is copyrighted by Chips and Technologies, Inc. You may not reproduce, transmit, transcribe,
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Restricted Rights Legend
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(c)(1)(ii) of the Rights in Technical Data and Computer Software clause at 252.277-7013.
Trademark Acknowledgment
CHIPS logotype, CHIPSlink, CHIPSPort, ELEAT, LeAPSet, NEAT, NEATsx, PEAK, SCAT,
SuperMathDX, SuperState, PRINTGINE, and WINGINE are registered trademarks of Chips and
Technologies, Inc.
CHIPSet, SuperMath, WinPC, and XRAM Video Cache are trademarks of Chips and Technologies,
Incorporated.
IBM®, is a registered trademarks of International Business Machines Corporation.
IBM® AT, XT, PS/2, Micro Channel, Enhanced Graphics Adapter, Color Graphics Adapter, Video
Graphics Adapter, IBM Color Display and IBM Color Display and IBM Monochrome Display are
trademarks of International Business Machines Corporation.
TRI-STATE® is a registered trademark of National Semiconductor Corporation.
VESA® is a registered trademark of Video Electronics Standards Association.
VL-Bus is a trademark of Video Electronics Standards Association.
All other trademarks are the property of their respective holders.
Disclaimer
This document is provided for the general information of the customer. Chips and Technologies, Inc.,
reserves the right to modify the information contained herein as necessary and the customer should ensure
that they have the most recent revision of the document. CHIPS makes no warranty for the use of its
products and bears no responsibility for any errors which may appear in this document. The customer
should be on notice that the field of personal computers is the subject of many patents held by different
parties. Customers should ensure that they take appropriate action so that their use of the products does not
infringe upon any patents. It is the policy of Chips and Technologies, Inc. to respect the valid patent rights
of third parties and not to infringe upon or assist others to infringe upon such rights.

Confidential Information Revision History
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Subject to change without notice
Revision History
Revision Date By Comment
0.1 4/24/95 RN Preliminary Release
1.0 7/12/95 RN/lc Official Release
1.1 8/21/95 SH/BB/lc Updated PCI Data Structure Table, removed reference to Emulation Registers
Updated Extended Mode Parameter Tables

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TABLE OF CONTENTS
FORWARD ..................................................................................................................................... 1
Terminology And Conventions .............................................................................................................................. 1
About This Manual .................................................................................................................................................1
CHAPTER 1- INTRODUCTION TO THE VGA BIOS............................................................. 2
VGA BIOS.............................................................................................................................................................. 2
Customization Support ...........................................................................................................................................2
BIOS Kits................................................................................................................................................................ 2
Licensing/Ordering CHIPS’ BIOS Products ...........................................................................................................3
Customer Support ................................................................................................................................................... 3
CHAPTER 2- BIOS FEATURES................................................................................................. 4
VGA BIOS Compatibility Target ........................................................................................................................... 4
PS/2 Compatibility...........................................................................................................................................4
AT Compatibility .............................................................................................................................................4
Multiple Bus Support..............................................................................................................................................4
Monitor Support ..................................................................................................................................................... 4
Display Boot/Display Type Configurations ............................................................................................................4
Extended Video Modes...........................................................................................................................................5
Audible Signals....................................................................................................................................................... 6
Flat-Panel Support .................................................................................................................................................. 7
Flat-Panel BIOS Operation .............................................................................................................................. 7
Vertical Compensation.....................................................................................................................................7
Horizontal Compensation ................................................................................................................................ 7
8x19 Font Support (Tall Fonts) ........................................................................................................................ 7
Inverse Video Switching ..................................................................................................................................7
Display Switching ............................................................................................................................................8
Simultaneous Display ......................................................................................................................................8
Extended Save and Restore .............................................................................................................................. 8
SMI and Hot Key Support ......................................................................................................................................8
Hardware Pop-Up Window Interface ...................................................................................................................... 8
PCI Support ............................................................................................................................................................ 9
Video BIOS...................................................................................................................................................... 9
System BIOS.................................................................................................................................................... 9
CHAPTER 3 - HARDWARE REQUIREMENTS ..................................................................... 10
65548 VGA Flat-Panel/CRT Controller ................................................................................................................10
Color Palette RAMDAC .......................................................................................................................................10
Monitor Detection Circuitry..................................................................................................................................10
Pixel Clocks.......................................................................................................................................................... 10
Memory Clock and Dot Clock .............................................................................................................................. 10

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CHAPTER 4- BIOS FUNCTION CALLS................................................................................. 11
Standard VGA BIOS Functions ............................................................................................................................ 11
Standard VGA BIOS Function Extensions ...........................................................................................................11
Set Video Mode - 00h ....................................................................................................................................11
Get Video State - 0Fh.....................................................................................................................................11
Save/Restore Video State - 1Ch ..................................................................................................................... 11
Get Save/Restore Buffer Size - 00h ................................................................................................................11
Save Video State - 01h ...................................................................................................................................12
Restore Video State - 02h .............................................................................................................................. 12
Extended BIOS Functions.....................................................................................................................................13
Get Controller Information - 00h ...................................................................................................................13
Set Clock - 02h ..............................................................................................................................................14
Get Refresh Rate Information - 04h (44KB BIOS only) ................................................................................14
Set Refresh Rate Information - 05h (44KB BIOS only) ................................................................................. 15
Get Linear Display Memory Information - 10h ............................................................................................. 15
Get Memory Map I/O Information - 11h (65548-PCI BIOS only) ................................................................ 16
Set Up Video Memory For Save/Restore - 13h (44K BIOS only) .................................................................16
Set Pop-Up Memory Mode - 14h (65548 44KB BIOS - VL-Bus only) ......................................................... 17
Reset Pop-Up Memory Mode - 14h (65548 44KB BIOS - VL-Bus only) .................................................... 17
Enable Pop-Up - 14h (65548 44KB BIOS - VL-Bus only) ...........................................................................18
Disable Pop-Up - 14h (65548 44KB BIOS - VL-Bus only) ..........................................................................18
Get Pop-Up Memory Offset - 14h (65548 44KB BIOS - VL-Bus only) ....................................................... 19
Notify Video BIOS for 3.3V/5V mixed mode switch - 15h ...........................................................................19
Notify Video BIOS for 5V mode switch - 15h ............................................................................................... 19
Get F65548 Information - 50h ....................................................................................................................... 20
Switch Display Device - 51h .......................................................................................................................... 21
Set Panel ON/OFF - 54h ................................................................................................................................ 21
Monitor Detect - 55h......................................................................................................................................22
Get Panel Type - 56h .....................................................................................................................................22
Set Flat-Panel Video Polarity - 5Ah ...............................................................................................................22
Set Vertical Compensation - 5Ch ...................................................................................................................23
Enable/Disable Vertical Compensation - 5Eh ................................................................................................ 24
Set Horizontal Compensation - 5Fh ...............................................................................................................25
Extended BIOS Save/Restore State - A0h ......................................................................................................26
Save Video State - A1h ..................................................................................................................................26
Restore Video State - A2h.............................................................................................................................. 27
VESA Extended VGA BIOS Functions (44KB BIOS Only) ................................................................................27
Return VBE Controller Information - 00h .....................................................................................................28
Return VBE Mode Information - 01h ............................................................................................................28
Set VBE Mode - 02h ......................................................................................................................................30
Get Current VBE Mode - 03h ........................................................................................................................ 30
Save/Restore Video State - 04h ...................................................................................................................... 31
Display Window Control - 05h ...................................................................................................................... 32
Get/Set Logical Scan Line Length - 06h ........................................................................................................33
Get/Set Display Start - 07h............................................................................................................................. 33
Get/Set Palette Data - 09h .............................................................................................................................. 34
Return VBE Protected Mode Interface - 0Ah .................................................................................................34
Display Power Management Extensions - 10h (44KB BIOS Only) ............................................................... 35

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INT 15h/INT 42h Hooks for the System BIOS .....................................................................................................36
POST Completion Notification - 5F31h (INT 15h Hook) ..............................................................................36
Calling Registers: AX - 5F31h Return Registers: None required. ............................................................. 36
Hook After Mode Set - 5F33h (BMP option: Set INT 15h or INT 42h, AX = 5F33/38/39h) ....................... 37
Multiple Panel Support - 5F34h (INT 15h Hook for 32KB BIOS only) ........................................................ 37
Set Panel Type - 5F34h (INT 15h Hook for 44KB BIOS only) .....................................................................38
Set Panel Type - 5F40h (Alternate Method - INT 15h Hook for 44KB BIOS only) ......................................38
Monitor Sensing Hook - 5F35h (INT 15h Hook) ........................................................................................... 38
Hook Before Mode Set - 5F38h (BMP option: Set INT 15h or INT 42h, AX = 5F33/38/39h) .................... 39
3.3V/5V Power Switching - 5F39h (For dual power supply systems - 32KB and 44KB BIOS) ..................39
3.3V/5V Power Switching - 5F42h (For dual power supply systems - Alternate Method for 44KB BIOS only)
.......................................................................................................................................................................39
CHAPTER 5- OEM UTILITY PROGRAMS ........................................................................... 42
BMP......................................................................................................................................................................42
Usage ............................................................................................................................................................. 42
Filenames....................................................................................................................................................... 42
Examples........................................................................................................................................................ 43
Commands ..................................................................................................................................................... 43
Help................................................................................................................................................................ 43
BMS Files ...................................................................................................................................................... 43
Error Messages...............................................................................................................................................44
Message Options............................................................................................................................................ 45
BIOS Features (44KB BIOS) ......................................................................................................................... 46
BIOS Features (32KB BIOS) ......................................................................................................................... 46
Enable/Disable Modes ...................................................................................................................................49
CRT Registers and Dot Clocks For All Extended Modes ..............................................................................50
CRT, Flat Panel and Simultaneous Boot Parameters ..................................................................................... 51
CRT Parameters .............................................................................................................................................51
Flat Panel and Simultaneous Video Parameters ............................................................................................. 52
Flat Panel and Simultaneous Video Parameters (Panel Type) ........................................................................52
Panel Control Parameters ............................................................................................................................... 53
Flat Panel Parameters .....................................................................................................................................54
Simultaneous Video Parameters ..................................................................................................................... 54
BMS Files (32 KB BIOS Only) ..................................................................................................................... 55
Built in Panel Support (44KB BIOS Only) ....................................................................................................56
ROMUTIL ............................................................................................................................................................ 56
Usage ............................................................................................................................................................. 56
Example ......................................................................................................................................................... 57

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APPENDIX A - BUILDING THE VGA BIOS ........................................................................... 58
APPENDIX B - EXTENDED CONTROL REGISTERS AND PARAMETER TABLES...... 59
Memory Control Registers 1 and 2 (XR04 and XR05) ......................................................................................... 59
Video Interface Register (XR28) .......................................................................................................................... 59
Mode Register (XR2B) .........................................................................................................................................59
Software Flag Register (XR1F) ............................................................................................................................. 59
Setup Registers ..................................................................................................................................................... 59
Half-Line Compare Register (XR19) .................................................................................................................... 59
Higher Page Map (XR10) and Lower Page Map (XR11) ..................................................................................... 59
132 Column Mode on 1024x768 Panel ................................................................................................................59
Software Flag Register (XR0F) ............................................................................................................................. 60
Software Flag Register (XR44) ............................................................................................................................. 60
Software Flag Register (XR45) ............................................................................................................................. 60
Extended Linear Mode Parameter Tables .............................................................................................................62
Extended Mode Parameter Tables ......................................................................................................................... 70
APPENDIX C - SUSPEND/RESUME PROCEDURE............................................................... 76
Introduction .......................................................................................................................................................... 76
Operation .............................................................................................................................................................. 76
Procedure .............................................................................................................................................................. 77

Confidential Information OEM Reference Guide
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FORWARD
This manual provides Original Equipment Manufacturers (OEMs) and end-users with information describing the
functions and features of the OC65548 and OC65548-PCI VGA BIOS.
Terminology And Conventions
COURIER FONT This font is used to specify commands typed by the user, as well as output produced
by the system.
Italic Type This type style is used to denote titles. It is also used to denote computer program
names, menu alternatives and other items at their first occurrence.
[] Items enclosed in square brackets are optional and may be ignored.
<> Items enclosed in less than and greater than symbols are keystrokes the user should
type.
hAn “h” which immediately follows a number indicates the value is hexadecimal.
Bordered Denotes important points.
About This Manual
This manual contains five chapters and three appendices. The purpose of each is as follows:
Chapter 1 This chapter summarizes the features of the VGA BIOS and the BIOS kits.
Chapter 2 This chapter describes the features of the VGA BIOS.
Chapter 3 This chapter explains the hardware requirements of the VGA BIOS.
Chapter 4 This chapter describes the standard function calls, extensions to the standard function calls and
extended function calls of the VGA BIOS.
Chapter 5 This chapter explains use of the OEM utility programs provided in the BIOS kits.
Appendix A This appendix explains how to create a binary version of the VGA BIOS from source code.
Appendix B This appendix explains how to determine and program extended control registers. Parameter tables
are also listed in this appendix.
Appendix C This appendix explains how to implement the Suspend/Resume Procedure in the system BIOS.

Confidential Information OEM Reference Guide
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CHAPTER 1- INTRODUCTION TO THE VGA BIOS
VGA BIOS
The OC65548, and OC65548-PCI VGA BIOS (hereafter referred to as 65548 BIOS) is an enhanced, high performance
BIOS that is used with the 65548 VGA Flat-Panel/CRT Controller to provide an integrated Flat-Panel VGA solution.
The BIOS supports the following features:
Full compatibility with the IBM VGA BIOS
Optimized for the 65548 VGA Flat-Panel/CRT controller
Support for monochrome LCD, 640x480 STN or TFT, 800x600 STN or TFT, and 1024x768 TFT
displays. Optional support for other displays.
Supports VESA BIOS Extensions, including VBE 2.0, VBE/DDC 1.0, and VBE/PM 1.0.
Supports either VESA local bus or PCI bus
Extended BIOS functions which offer easy access to 65548 features and capabilities
Support for simultaneous display
Customization Support
The 65548 BIOS design to allows the user to customize of values in the binary version of the BIOS. This capability
enables an OEM to create a custom version of the BIOS without access to the source code. Customization is
accomplished with the BMP548 utility included with the BIOS kits.
BIOS Kits
The 65548 BIOS is available in three kit formats. These kits and their contents are as follows:
SE65548 VGA BIOS Evaluation Kit:
•Evaluation diskette (Evaluation copy of BIOS and utility programs)
•OC65548 VGA BIOS OEM Reference Guide
•Release notes
•Software Incident Report (SIR) forms
SK65548 VGA BIOS Binary Kit:
•Binary diskette (Master copy of BIOS and utility programs)
•OC65548 VGA BIOS OEM Reference Guide
•Release notes
•Software Incident Report (SIR) forms
SC65548 VGA BIOS Source Code Kit:
•Source code diskette
•SK65548 VGA BIOS binary kit

Confidential Information OEM Reference Guide
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Licensing
Please contact your Chips and Technologies, Inc. representative for information on how to obtain a production copy of
the software.
Customer Support
CHIPS software products are supported by field application engineers located in each sales office. If you encounter a
problem, or have any questions regarding a CHIPS software product, please complete a copy of the Software Incident
Report form included with your product. Forward the completed form to the local CHIPS sales office or to the
following address:
Chips and Technologies, Inc.
2950 Zanker Road
San Jose, CA 95134
Attn.: Software Product Support
FAX SIR forms to:
[phone]

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CHAPTER 2- BIOS FEATURES
The 65548 BIOS is fully compatible with the IBM VGA BIOS and contains many additional features that support the
65548 Flat-Panel/CRT VGA controller.
VGA BIOS Compatibility Target
The 65548 BIOS can be configured to operate in a manner compatible with an IBM PS/2 motherboard VGA BIOS or
IBM AT VGA adapter BIOS. The compatibility target can be configured with the BMP548 utility program.
PS/2 Compatibility
If PS/2 BIOS compatibility is selected, direct switching between color and monochrome video modes is supported
when the VGA is the only adapter in the system. The 65548 BIOS supports color modes when a secondary
monochrome display adapter or Hercules adapter is installed in the system. The BIOS supports monochrome modes
when a secondary CGA is installed in the system. This is the default operating mode.
AT Compatibility
If AT BIOS compatibility is selected, direct switching between color and monochrome video modes is NOT supported
when the VGA is the only adapter in the system. The equipment byte must be set for color before switching from a
monochrome mode to a color mode and vice-versa. The 65548 BIOS supports color modes when a secondary MDA or
Hercules adapter is installed in the system. In addition, the BIOS supports monochrome modes when a secondary
CGA is installed in the system.
Multiple Bus Support
The 65548 BIOS supports multiple bus specifications:
•VESA Local Bus
•PCI Local Bus, Revision 2.0
Monitor Support
The 65548 BIOS supports interlaced and non-interlaced analog monitors (VGA color, VGA monochrome), but the
65548 does not support digital monitors.
Note: Multiple frequency monitors are supported as analog monitors.
Display Boot/Display Type Configurations
The 65548 BIOS can be configured to boot on a CRT, Flat-Panel, or Simultaneous display (CRT and Flat-Panel are
both active). The OEM may select the display boot device by changing BIOS parameters with the BMP548 utility
program. The parameters which select the boot display device also select the CRT configuration. The available display
boot devices are:
•CRT Boot
•Flat-Panel Boot
•Simultaneous Display Boot

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Extended Video Modes
The 65548 BIOS supports all standard modes and the following extended modes for analog monitors. If the total video
memory size is less than the memory required by the given mode, the 65548 BIOS will not switch to that mode.
Table 1: CRT Extended Video Modes
Mode VESA Mode Resolution Type Color Vertical Refresh
20h 640x480 Linear PackPixel 16 60, 72, 75 Hz
22h 800x600 Linear PackPixel 16 56, 60, 72, 75 Hz
24h(I) 1024x768 Linear PackPixel 16 43, 60, 70, 75 Hz
28h(I) 1280x1024 Linear PackPixel 16 43 Hz
30h 101h 640x480 Linear PackPixel 256 60, 72, 75 Hz
32h 103h 800x600 Linear PackPixel 256 56, 60, 72, 75 Hz
34h(I) 105h 1024x768 Linear PackPixel 256 43, 60, 70, 75 Hz
40h 110h 640x480 Linear PackPixel 32K 60, 72, 75 Hz
41h 111h 640x480 Linear PackPixel 64K 60, 72, 75 Hz
42h 113h 800x600 Linear PackPixel 32K 56, 60 Hz
43h 114h 800x600 Linear PackPixel 64K 56, 60 Hz
50h 112h 640x480 Linear PackPixel 16M 60 Hz
60h 132x25 Text (8x16) 16 70 Hz
61h 132x50 Text (8x8) 16 70 Hz
6Ah/70h 102h 800x600 Planar 16 60 Hz
72h/75h(I) 104h 1024x768 Planar 16 43, 60, 70, 75 Hz
76h(I) 106h 1280x1024 Planar 16 43 Hz
79h 101h 640x480 PackPixel 256 60, 72, 75 Hz
7Ch 103h 800x600 PackPixel 256 56, 60, 72, 75 Hz
7Eh(I) 105h 1024x768 PackPixel 256 43, 60, 70, 75 Hz

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Table 2: Flat-Panel Extended Video Modes
Mode VESA Mode Resolution Type Color Panel CLK
20h 640x480 Linear PackPixel 16 25 MHz
22h 800x600 Linear PackPixel 16 25 MHz
24h 1024x768 Linear PackPixel 16 25 MHz
28h 1280x1024 Linear PackPixel 16 25 MHz
30h 101h 640x480 Linear PackPixel 256 25 MHz
32h 103h 800x600 Linear PackPixel 256 25 MHz
34h 105h 1024x768 Linear PackPixel 256 25 MHz
40h 110h 640x480 Linear PackPixel 32K 50 MHz
41h 111h 640x480 Linear PackPixel 64K 50 MHz
42h 113h 800x600 Linear PackPixel 32K 50 MHz
43h 114h 800x600 Linear PackPixel 64K 50 MHz
50h 112h 640x480 Linear PackPixel 16M 75 MHz
60h 132x25 Text (8x16) 16 25 MHz
61h 132x50 Text (8x8) 16 25 MHz
6Ah/70h 102h 800x600 Planar 16 25 MHz
72h/75h 104h 1024x768 Planar 16 25 MHz
76h 106h 1280x1024 Planar 16 25 MHz
79h 101h 640x480 PackPixel 256 25 MHz
7Ch 103h 800x600 PackPixel 256 25 MHz
7Eh 105h 1024x768 PackPixel 256 25 MHz
Note: 1. The Flat Panel cannot support Interlaced modes. All modes are Non-Interlaced. The default Flat-Panel size
is 640x480.
2. The Flat-Panel clock value shown in the preceding table is for a 640x480 DD Panel. It may require
different clock values for different Flat-Panel resolutions.
3. VESA modes may use either a linear or a paged frame buffer. See the VBE 2.0 function documentation for
more information on specifying the frame buffer format for a mode.
4. (I) = Interlaced
Audible Signals
If an error is encountered when the 65548 Flat-Panel/CRT VGA controller is initialized, the 65548 BIOS will return a
beep pattern consisting of one long beep and several short beeps. (See Table 3.)
Table 3: Audible Signals
Beep Pattern Error Condition
1 Long, 2 Short Horizontal retrace failed,
1 Long, 3 Short DAC test failed,
1 Long, 4 Short Monitor sense failed,
1 Long, 5 Short Vertical retrace failed,
1 Long, 6 Short Video memory test failed.

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Flat-Panel Support
The 65548 BIOS provides support for features used in conjunction with a Flat-Panel display. The type of Flat-Panel
display can be changed with the BMP548 utility program. The default Flat-Panel type is a 640x480 monochrome dual-
drive LCD.
Flat-Panel BIOS Operation
The 65548 BIOS operates as if the Flat-Panel is a VGA display independent of the display size. This allows display of
all video modes (00h - 13h). Flat-Panels of lower resolution than the video mode will display a partial image that is left
and top justified.
Vertical Compensation
The 65548 BIOS supports the following vertical compensation modes for Flat-Panel operation:
•None Image is top justified.
•Automatic Centering Image is automatically centered vertically.
•Non-Automatic Centering Image display start location is specified.
•Tall Font/Text Compensation Text is compensated by stretching the font in the hardware.
•Line Replication/Graphic Compensation Line replication stretches graphics im age to fill the display.
The Vertical Compensation can be set by using function 5F5Eh (Enable/Disable Vertical Compensation). Vertical
Compensation status can be read by using function 5F50h, (See F65548 Information).
Horizontal Compensation
The 65548 BIOS supports the following horizontal compensation modes for Flat-Panel operation:
•None Image is left justified.
•Automatic Centering Image is automatically centered horizontally.
•Non-Automatic Centering Image display start location is specified.
•Text Compression 720 dot wide Hercules applications can be compressed to fit on 640
horizontal resolution panels by either adding the eighth and ninth
pixels or deleting the ninth pixel.
•Automatic Horizontal Doubling 640 dot wide images can be automatically doubled to fill 1280 dot
wide flat panels.
The Horizontal Compensation can be set with function 5F5Fh.
8x19 Font Support (Tall Fonts)
The 65548 BIOS supports a special Tall Font in Flat-Panel operation which provides a larger, more readable font
without the distortion that can be caused by graphics/text compensation. The Tall Font replaces the standard 8x16
VGA font and can be enabled or disabled with function 5F5Eh (Enable/Disable Text Compensation).
Inverse Video Switching
The 65548 BIOS supports inverted and non-inverted video display. The BIOS directly initializes the video polarity on
boot. The video polarity can be switched with function 5F5Ah (Set Flat-Panel Video Polarity).

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Display Switching
The 65548 BIOS provides support for switching among a Flat-Panel, CRT, CRT Zoom and Simultaneous display at
run time. Function 5F51h (Switch Display Device) performs the switching function.
Simultaneous Display
The 65548 BIOS can be configured to operate an analog CRT monitor and monochrome 640x480 flat panel at the same
time. Function 5F51h (Switch Display Device) enables and disables Simultaneous display operation.
Extended Save and Restore
The 65548 BIOS provides functions to save and restore the state of the 65548 Flat-Panel/CRT VGA controller. This
includes all standard and extended registers, the memory latches and the attribute flip/flop state. The functions
provided are 5FA0h (Extended BIOS Save/Restore State), 5FA1h (Save Video State), and 5FA2h (Restore Video
State).
SMI and Hot Key Support
An alternate INT 10h entry point (word pointer) is located at 8Bh in the BIOS which will bypass the STI instruction at
the beginning of the usual INT 10h handler. STI instructions are not allowed during processing of an SMI, or System
Management Interrupt.
The CHIPS 65548 BIOS and CHIPS Flat-Panel Windows drivers are designed to support display switching with hot
keys. The following describes how to use the video BIOS to implement hot key display switching. The system BIOS
hot key function handler should call the video BIOS switch display function (INT 10h, function 5F51h) when the
switch display hot key is pressed.
If the processor is an xSL CPU, the SMI normally handles the hot key. The system BIOS must temporarily patch the
INT 10h entry point prior to calling the video BIOS during the SMI. The INT 10h vector should be set to the point to
offset 8Bh in the video BIOS, bypassing the STI instruction at the beginning of the usual entry point. After the INT
10h returns to the system BIOS, the system BIOS should restore the original INT 10h vector prior to returning from the
hot key interrupt.
The video BIOS switch display function will switch the displays and program a flag in bits 0-3 of extended register
XR1F of the 65548 chip. These bits are dedicated to the CHIPS Flat-Panel Windows display drivers.
Hardware Pop-Up Window Interface
The 65548 VGA Flat-Panel/CRT Controller has the capability of overlaying a 32x32 / 64x64 / 128x128 area of screen
with the off-screen data stored in different formats. The off-screen data could be an AND/XOR format cursor
(Windows or OS/2), or a monochrome - 2 bit per pixel format bit map. The 65548 can enable both the pop-up or
hardware cursor function, but not both at the same time. SMI hot key function controls the switching. Under Windows
and OS/2, the display driver has to know when to switch to the software cursor or the hardware cursor. The hot-key
usually generates an SMI, and the SMI handler must inform driver about this change. The 65548 BIOS provides an
interface between the driver and SMI to support the pop-up through the 5F14H function.

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PCI Support
Video BIOS
The 65548-PCI Video BIOS is developed for use with PCI Local Bus board configurations as defined in the PCI Local
Bus Specification, Rev 2.0. The 65548-PCI BIOS has Word Pointers to the PCI Data Structure at offset
C000:18h/E000:18h. The PCI Data Structure is defined as follows:
Table 4: PCI Data Structure
Offset Length Data Description
0 4 PCIR Signature
4 2 102Ch Vendor ID
6 2 00DCh Device ID
8 2 0000h Pointer to vital product data
A2 0018h PCI data structure length
C1 00h PCI structure revision
D300h,00h,03h Class code
10 2 ???? Image Length in 512 Byte units:
0040h = 32KB
0050h = 40KB
0058h = 44KB
12 2 0000h Revision level of code/data
14 1 00h Code Type
15 1 80h Indicator
16 2 0000h Reserved
System BIOS
The 65548 PCI Flat Panel/CRT controller does not support expansion ROM Base Address at offset 30h in the
configuration space. The video BIOS is usually merged with the system BIOS and is located at Address E000:0 in the
system. To find the video device during power up, the system BIOS reads Class Code at offset 09h (00h,00h,3h) in the
configuration space . The system BIOS then looks for PCIR signatures in the C000/E000 segment (Word Pointer to the
PCIR string is at C000:18h/E000:18h) followed by the video device Class Code (00h,00h,03h) at offset 0Dh in the PCI
Data Structure of the video BIOS. When the system BIOS finds the video device, it should map the video BIOS at a
very high address, then copy the video BIOS at Address C000:0/E000:0.
Note: The PCI BIOS should be BMPed for the correct segment.

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Revision 1.1 10/2/95 10 OC65548
Subject to change without notice
CHAPTER 3- HARDWARE REQUIREMENTS
This chapter describes the external hardware requirements for the 65548 BIOS. For more information regarding
hardware implementation, please refer to the 65548 High Performance Flat-Panel/CRT VGA Controllers Data Sheet,
Chips & Technologies, Inc.
65548 VGA Flat-Panel/CRT Controller
The 65548 BIOS requires a Chips and Technologies 65548 VGA Flat-Panel/CRT Controller.
Color Palette RAMDAC
The 65548 BIOS assumes that the 65548 on-chip color palette/DAC is used.
Monitor Detection Circuitry
The monitor detection circuitry should be implemented in a manner compatible with the IBM AT VGA adapter. The
65548 BIOS assumes that the monitor detection circuitry, if present, is attached to the SENSE pin of the 65548 Flat-
Panel/CRT VGA controller.
Pixel Clocks
The 65548 BIOS requires specific clock frequencies to operate. The 65548 BIOS assumes that the on-chip clock
synthesizer generates the clock signals.
Table 5 specifies the values for the Clock Select and Feature Control outputs necessary to use the specified clock
source and the frequencies expected by the 65548 BIOS.
Table 5: Pixel Clock Selection Values and Frequencies
MSR or XR54
Bits 3,2 Pixel Clock Selection Pixel Clock Frequency Comments
0, 0 CLK0 25.175 MHz. (Analog)
0, 1 CLK1 28.322 MHz. (Analog)
1, X CLK2 Programmable Program XR33,XR30,XR31,XR32
CRT Mode:
MSR =Miscellaneous Output Register (Write at 3C2h, Read at 3CCh)
Flat-Panel/Simultaneous Mode:
XR54 =Extended Register (Read/Write at 3D6h-3D7h)
Memory Clock and Dot Clock
The 65548 BIOS allows the user to program the Dot Clock (Pixel Clock) and the Memory Clock using the on-chip
clock synthesizer.

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Revision 1.1 10/2/95 11 OC65548
Subject to change without notice
CHAPTER 4- BIOS FUNCTION CALLS
Standard VGA BIOS Functions
The 65548 BIOS uses the same function and sub-function calls that are implemented in the IBM VGA BIOS.
Standard VGA BIOS Function Extensions
The 65548 BIOS provides a set of extended functions that are implemented as extensions to the standard Set Video
Mode (00h), Get Video State (0Fh) (see Table 6), and Save/Restore Video State (1Ch) functions. They are fully
supported by the other standard VGA BIOS function calls.
Set Video Mode - 00h
The Set Video Mode function sets the display mode used by the 65548 Flat-Panel/CRT VGA controller.
Calling Registers:
AH -00h Set Video Mode
AL -Display Mode
Return Registers:
Nothing
Get Video State - 0Fh
The Get Video State function returns the screen width in character columns, video display mode, and active display
page.
Calling Registers:
AH -0Fh Get Video State
Return Registers:
AH -Number of Character Columns
AL -Display Mode
BH -Active Display Page
Save/Restore Video State - 1Ch
This function and its sub-functions save and restore specified video environment parameters (BIOS data area, color
palette, and registers). The 65548 BIOS also allows the extended registers and emulation mode registers to be saved.
This is specified by CX:Bit 15.
Get Save/Restore Buffer Size - 00h
Calling Registers:
AH -1Ch Save/Restore Video State Function
AL -00h Get Save/Restore Buffer Size
CX -Save/Restore Options:
Bit 0 Video Hardware State
Bit 1 Video BIOS Data Areas
Bit 2 Video DAC State and Color Registers
Bit 15 Extended Registers
Return Registers:
AL -1Ch Function was successful
BX -Buffer Size Required in 64 byte blocks

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Save Video State - 01h
Calling Registers:
AH -1Ch Save/Restore Video State Function
AL -01h Save Video State
CX -Save/Restore Options:
Bit 0 Video Hardware State
Bit 1 Video BIOS Data Areas
Bit 2 Video DAC State and Color Registers
Bit 15 Extended Registers
ES -Segment of Save Area
BX -Offset of Save Area
Return Registers:
AL -1Ch Function was successful
Restore Video State - 02h
Calling Registers:
AH -1Ch Save/Restore Video State Function
AL -02h Save Video State
CX -Save/Restore Options:
Bit 0 Video Hardware State
Bit 1 Video BIOS Data Areas
Bit 2 Video DAC state and Color Registers
Bit 15 Extended Registers
ES -Segment of Restore Area
BX -Offset of Restore Area
Return Registers:
AL -1Ch Function was successful

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Revision 1.1 10/2/95 13 OC65548
Subject to change without notice
Extended BIOS Functions
The 65548 BIOS provides a set of function calls to control operation of the extended features of the 65548 Flat-
Panel/CRT VGA Controller. These function calls are implemented as sub-functions under the extended VGA control
function (5Fh).
Table 6: 65548 BIOS Extended Functions
AH AL Function AH AL Function
5Fh 00h Get Controller Information 5Fh 15h Notify Video BIOS of 5V mode switch
5Fh 02h Set Clock 5Fh 50h Get F65548 Information
5Fh 04h Get Refresh Rate Information 5Fh 51h Switch Display Device
5Fh 05h Set Refresh Rate Information 5Fh 54h Set Panel ON/OFF
5Fh 10h Get Linear Display Memory Information 5Fh 55h Monitor Detect
5Fh 11h Get Memory Map I/O Information (PCI) 5Fh 56h Get Panel Type
5Fh 13h Set Up Video Memory for Save/Restore 5Fh 5Ah Set Flat-Panel Video Polarity
5Fh 14h Set Pop-Up Memory Mode 5Fh 5Ch Set Vertical Compensation
5Fh 14h Reset Pop-Up Memory Mode 5Fh 5Eh Enable/Disable Vertical Compensation
5Fh 14h Enable Pop-Up 5Fh 5Fh Set Horizontal Compensation
5Fh 14h Disable Pop-Up 5Fh A0h Extended BIOS Save/Restore State
5Fh 14h Get Pop-up Memory Offset 5Fh A1h Save Video State
5Fh 15h Notify Video BIOS of 3.3V/5V mixed 5Fh A2h Restore Video State
Get Controller Information - 00h
This sub-function returns configuration information about the 65548 VGA system.
Calling Registers:
AH -5Fh Extended VGA Control Function
AL -00h Get controller information
Return Registers:
AL -5Fh
AH -Return Status:
00h Function failed
01h Function was successful
BL -Chip type and version number
D7-D3 = Chip Type
00000b 82C451
00010b 82C452 or 82C452A
00100b 82C455
00110b 82C453
01000b 82C450
01010b 82C456
01100b 82C457
01110b F65520
10000b F65530/525
10010b F65510
10100b F64200
10110b F64300
11000b F65535