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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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
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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
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infringe upon any patents. It is the policy of Chips and Technologies, Inc. to respect the valid patent rights
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Confidential InformationRevision History
Revision History
RevisionDate By Comment
0.14/24/95RNPreliminary Release
1.07/12/95RN/lcOfficial Release
1.18/21/95SH/BB/lcUpdated PCI Data Structure Table, removed reference to Emulation Registers
Updated Extended Mode Parameter Tables
Terminology And Conventions .............................................................................................................................. 1
About This Manual .................................................................................................................................................1
CHAPTER 1 - INTRODUCTION TO THE VGA BIOS ............................................................. 2
Customization Support ...........................................................................................................................................2
Customer Support ................................................................................................................................................... 3
CHAPTER 2 - BIOS FEATURES ................................................................................................. 4
AT Compatibility ............................................................................................................................................. 4
Multiple Bus Support.............................................................................................................................................. 4
Monitor Support ..................................................................................................................................................... 4
Display Boot/Display Type Configurations ............................................................................................................ 4
Extended Video Modes........................................................................................................................................... 5
Flat-Panel Support .................................................................................................................................................. 7
8x19 Font Support (Tall Fonts) ........................................................................................................................ 7
Inverse Video Switching .................................................................................................................................. 7
Extended Save and Restore .............................................................................................................................. 8
SMI and Hot Key Support ......................................................................................................................................8
PCI Support ............................................................................................................................................................ 9
Video BIOS...................................................................................................................................................... 9
System BIOS....................................................................................................................................................9
Color Palette RAMDAC .......................................................................................................................................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
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
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
Get Panel Type - 56h ..................................................................................................................................... 22
Set Flat-Panel Video Polarity - 5Ah ...............................................................................................................22
Set Vertical Compensation - 5Ch ................................................................................................................... 23
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
Flat Panel and Simultaneous Video Parameters ............................................................................................. 52
Flat Panel and Simultaneous Video Parameters (Panel Type) ........................................................................52
Panel Control Parameters ............................................................................................................................... 53
Example ......................................................................................................................................................... 57
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APPENDIX A - BUILDING THE VGA BIOS ........................................................................... 58
APPENDIX B - E XTENDED CONTROL REGISTERS AND PARAMETER TABLES...... 59
Memory Control Registers 1 and 2 (XR04 and XR05) ......................................................................................... 59
Video Interface Register (XR28) .......................................................................................................................... 59
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 FONTThis font is used to specify commands typed by the user, as well as output produced
by the system.
Italic TypeThis 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.
BorderedDenotes important points.
About This Manual
This manual contains five chapters and three appendices. The purpose of each is as follows:
Chapter 1This chapter summarizes the features of the VGA BIOS and the BIOS kits.
Chapter 2This chapter describes the features of the VGA BIOS.
Chapter 3This chapter explains the hardware requirements of the VGA BIOS.
Chapter 4This chapter describes the standard function calls, extensions to the standard function calls and
extended function calls of the VGA BIOS.
Chapter 5This chapter explains use of the OEM utility programs provided in the BIOS kits.
Appendix AThis appendix explains how to create a binary version of the VGA BIOS from source code.
Appendix BThis appendix explains how to determine and program extended control registers. Parameter tables
are also listed in this appendix.
Appendix CThis appendix explains how to implement the Suspend/Resume Procedure in the system BIOS.
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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
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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:
(408) 894-2086
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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.
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.)
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 dualdrive 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:
•NoneImage is top justified.
•Automatic CenteringImage is automatically centered vertically.
•Non-Automatic CenteringImage display start location is specified.
•Tall Font/Text CompensationText is compensated by stretching the font in the hardware.
•Line Replication/Graphic CompensationLine 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:
•NoneImage is left justified.
•Automatic CenteringImage is automatically centered horizontally.
•Non-Automatic CenteringImage display start location is specified.
•Text Compression720 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 Doubling640 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
OffsetLengthDataDescription
04PCIRSignature
42102ChVendor ID
6200DChDevice ID
820000hPointer to vital product data
A20018hPCI data structure length
C100hPCI structure revision
D300h,00h,03hClass code
102????Image Length in 512 Byte units:
0040h = 32KB
0050h = 40KB
0058h = 44KB
1220000hRevision level of code/data
14100hCode Type
15180hIndicator
1620000hReserved
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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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 FlatPanel/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=Miscellaneous Output Register (Write at 3C2h, Read at 3CCh)
Flat-Panel/Simultaneous Mode:
XR54=Extended Register (Read/Write at 3D6h-3D7h)
Pixel Clock
Selection
Pixel Clock
FrequencyComments
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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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-00hSet 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-0FhGet 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-1ChSave/Restore Video State Function
AL-00hGet Save/Restore Buffer Size
CX-Save/Restore Options:
Bit 0Video Hardware State
Bit 1Video BIOS Data Areas
Bit 2Video DAC State and Color Registers
Bit 15Extended Registers
Return Registers:
AL-1ChFunction was successful
BX-Buffer Size Required in 64 byte blocks
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Save Video State - 01h
Calling Registers:
AH-1ChSave/Restore Video State Function
AL-01hSave Video State
CX-Save/Restore Options:
ES-Segment of Save Area
BX-Offset of Save Area
Return Registers:
AL-1ChFunction was successful
Restore Video State - 02h
Calling Registers:
AH-1ChSave/Restore Video State Function
AL-02hSave Video State
CX-Save/Restore Options:
ES-Segment of Restore Area
BX-Offset of Restore Area
Return Registers:
AL-1ChFunction was successful
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Bit 0Video Hardware State
Bit 1Video BIOS Data Areas
Bit 2Video DAC State and Color Registers
Bit 15Extended Registers
Bit 0Video Hardware State
Bit 1Video BIOS Data Areas
Bit 2Video DAC state and Color Registers
Bit 15Extended Registers
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Extended BIOS Functions
The 65548 BIOS provides a set of function calls to control operation of the extended features of the 65548 FlatPanel/CRT VGA Controller. These function calls are implemented as sub-functions under the extended VGA control
function (5Fh).
Table 6: 65548 BIOS Extended Functions
AHALFunctionAHALFunction
5Fh00hGet Controller Information5Fh15hNotify Video BIOS of 5V mode switch
5Fh02hSet Clock5Fh50hGet F65548 Information
5Fh04hGet Refresh Rate Information5Fh51hSwitch Display Device
5Fh05hSet Refresh Rate Information5Fh54hSet Panel ON/OFF
5Fh10hGet Linear Display Memory Information5Fh55hMonitor Detect
5Fh11hGet Memory Map I/O Information (PCI)5Fh56hGet Panel Type
5Fh13hSet Up Video Memory for Save/Restore5Fh5AhSet Flat-Panel Video Polarity
5Fh14hSet Pop-Up Memory Mode5Fh5ChSet Vertical Compensation
5Fh14hReset Pop-Up Memory Mode5Fh5EhEnable/Disable Vertical Compensation
5Fh14hEnable Pop-Up5Fh5FhSet Horizontal Compensation
5Fh14hDisable Pop-Up5FhA0hExtended BIOS Save/Restore State
5Fh14hGet Pop-up Memory Offset5FhA1hSave Video State
5Fh15hNotify Video BIOS of 3.3V/5V mixed5FhA2hRestore Video State
Get Controller Information - 00h
This sub-function returns configuration information about the 65548 VGA system.
Calling Registers:
AH-5FhExtended VGA Control Function
AL-00hGet controller information
11010b F65540
11011b F65545
110111b F65548
D1-D0 = Revision number (65548)
D2-D0 = Revision number (other)
BHVideo memory available
0 = 256KB
1 = 512KB
2 = 1MB
3 = Reserved
Set Clock - 02h
This sub-function is used to program the internal clock synthesizer with a given frequency. The selected list of
frequencies is shown below.
Calling Registers:
AH-5FhExtended VGA Control Function
AL-02hSet Dot Clock/Memory Clock
IFBH-02Set Dot Clock
03Set Memory Clock
BL-12 to 80 MHz (decimal)
IFBH-FFhProgram Default Dot and Memory Clocks
Return Registers:
AL-5Fh
AH-Return Status:
00hFunction failed
01hFunction was successful
Get Refresh Rate Information - 04h (44KB BIOS only)
This sub-function returns the current setting of the vertical refresh rate for the given mode, and the list of available
vertical refresh rates for the mode.
Calling Registers:
AH-5FhExtended VGA BIOS Function
AL-04hGet refresh rate
BL-Mode Number
Return Registers:
BL-Available refresh rates, indicated by setting one or more bits as follows:
Bit7Reserved
BH-Currently set refresh rate, one bit set as above
CX-Reserved
AL-5FhExtended VGA BIOS Function Supported
AH-Function Return Status:
00hFunction failed
01hFunction was successful
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Set Refresh Rate Information - 05h (44KB BIOS only)
This sub-function sets a new vertical refresh rate for the given mode. If the mode is currently active, the BIOS will
program the CRT controller for the new refresh rate. If the mode is not active, the new refresh rate will be programmed
the next time this mode is set. The refresh rates are effective in the CRT modes only.
Calling Registers:
AH-5FhExtended VGA BIOS Function
AL-05hSet Refresh Rate
BL-Mode Number
BH-Set refresh rate, indicated by setting one bit as follows:
Bit0Interlaced
Bit156Hz
Bit260Hz
Bit370Hz
Bit472Hz
Bit575Hz
Bit6Reserved
Bit7Reserved
CX-Reserved
Return Registers:
AL-5FhExtended VGA BIOS Function Supported
AH-Function Return Status:
00hFunction failed
01hFunction was successful
Get Linear Display Memory Information - 10h
This sub-function returns information regarding the linear memory starting address, size and width.
Calling Registers:
AH-5FhExtended VGA Control Function
AL-10hGet Linear Display Memory Information
Return Registers:
AL-5Fh
AH-Return Status:
00hFunction failed
01hFunction was successful
BX-Display Memory Base Address (High)
CX-Display Memory Base Address (Low)
SI-Display Memory Size (High)
DI-Display Memory Size (Low)
DX-Display Width in bytes
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Get Memory Map I/O Information - 11h (65548-PCI BIOS only)
This sub-function returns information regarding memory mapped I/O on a PCI configuration.
Calling Registers:
AH-5FhExtended VGA Control Function
AL-11hGet Memory Mapped I/O Information
Return Registers:
AL-5Fh
AH-Return Status:
00hFunction failed
01hFunction was successful
BX-Memory Mapped I/O Base Address (High)
CX-Memory Mapped I/O Base Address (Low)
SI-Reserved
DI-Reserved
DX-Reserved
Set Up Video Memory For Save/Restore - 13h (44K BIOS only)
This sub-function sets up for saving/restoring all of the video memory in 64KB blocks (the appropriate 64KB block is
made available at location A000:0000 for reading/writing).
Calling Registers:
AX-5F13h
BX-0000h
CX-nth 64K block to save/restore where (n = 0,1,2,....)
Return Registers:
64K block of video memory will be mapped to A000:0000 for saving/restoring.
This sub-function sets the pop-up memory mode. The Video BIOS saves the necessary registers in the 32-byte buffer
passed by the SMI, and then sets up registers for dumping the pop-up bit map into the off-screen video memory. If the
BLTer is in System to Screen BLT mode, the Video BIOS may return with an error to indicate that video memory
cannot be accessed at this time, and that the SMI handler should exit SMI mode in this situation. Note: If the
function is successful, then the SMI must call the Video BIOS with AX = 5F14h, BL = 01h to restore video controller
registers after the SMI loads the pop-up screen into the video memory.
Calling Registers:
AX-5F14h Set Pop-Up Function
BL-00hSet Pop-Up Memory Mode
ES:DX -Pointer to 32 byte buffer for Video BIOS in SMI
Return Registers:
ES:DI-Pointer to Pop-up screen memory @ A000h
BL-00hFunction Error (System to Screen BLT mode)
This sub-function resets the pop-up memory mode. The Video BIOS restores all the registers changed by the Set PopUp Memory Function from the buffer passed by the SMI.
Calling Registers:
AX-5F14h Set Pop-Up Function
BL-01hReset Pop-Up Memory Mode
ES:DX -Pointer to 32 byte buffer for Video BIOS in SMI
This sub-function returns pop-up memory offset. This offset should be added to the video memory start address to get
the absolute pop-up memory address.
Calling Registers:
AX-5F14h Set Pop-Up function
BL-04hGet Pop-Up memory offset
Notify Video BIOS for 3.3V/5V mixed mode switch - 15h
This sub-function notifies the Video BIOS to switch to 3.3V/5V mixed mode. If the Video BIOS cannot switch
immediately, then it will set an internal flag to perform the switch later, when switching is possible.
Calling Registers:
AX-5F15h
BH-00h
BL-55h
Return Registers:
BL-00hFunction supported, but cannot change to 3.3V at this time
01hFunction supported, switched to 3.3V
55hFunction not supported
Notify Video BIOS for 5V mode switch - 15h
This sub-function notifies the Video BIOS to switch to 5V mode. If the Video BIOS cannot switch immediately, then
it will set an internal flag to perform the switch later, when switching is possible.
Calling Registers:
AX-5F15h
BH-01h
BL-55h
Return Registers:
BL-01hFunction Supported, switched to 5V
-55hFunction not Supported
Revision 1.110/2/9519OC65548
Subject to change without notice
Confidential InformationOEM Reference Guide
Get F65548 Information - 50h
This sub-function returns the current CRT/Flat-Panel information.
Calling Registers:
AH-5FhExtended VGA Control Function
AL-50hGet F65548 Information
Return Registers:
AL-5Fh
AH-Return Status:
00hFunction failed
01hFunction was successful
BX-Flat-Panel Horizontal size in pixels
CX-Flat-Panel Vertical size in pixels
DX-F65548 status