Paradise/Western Digital Super VGA Chips.
Max mem Max 16col 256 col
PVGA1A 512k/1M 800x600 640x480
WD90C00 512k/1M 1024x768 800x600 also known as PVGA1B
WD90C10 256k 640x480 320x200
WD90C11 512k 1024x768 800x600
WD90C20 800x600 640x480? LCD/plasma controller derived
from WD90C00. 32 grey scales
WD90C22 As C20, but 64 grey scales
WD90c24 208pin Max 1M RAM, 1280x1024 16c, 1024x768 256c.
Builtin 15/16bit DAC. LCD controller with BitBLT, line draw and
VESA local bus interface. Supports 3.3V or 5V operation
WD90c24A
WD90c26A LCD controller. Can drive LCD
and CRT simultaneously. 3.3V
WD90C30 1M 1024x768 1024x768 (D-step)
WD90C31 1M 1280x1024 1024x768 (1DW - accelerator) Hardware
Cursor, BitBLT.
WD90C33 2M 1280x1024 Accelerator. as WD90c31, but
with 8-level instruction FIFO.
VESA local bus interface.
WD90C35 Next version?
Support chips:
WD90c55 Color LCD interface for WD90c20/22
WD90c56 Local Bus Interface for WD90c31
94h (W): Setup Register (Micro Channel)
102h (R/W): VGA Sleep Register (setup mode only)
bit 0 VGA enabled if set.
1-7 Reserved.
Note: this register can only be accessed in setup mode.
3B8h (W): Hercules/MDA Mode Control Register
bit 0 High Resolution (80x25) mode enabled if set
1 If set allows access to 3BFh, if clear disables access to 3BFh and
thus forces alpha mode.
3 If set video is active
5 If set blinking is enabled
7 (Hercules mode) If bit 1 is set and 3BFh bit 0 is set, this bit
selects the page to display. 0: B000h:0, 1: B800h:0
Note: This register is only available in MDA/Hercules compatibility modes
3BAh (R): CRT Status Register MDA Operation
bit 0 If set either blanking or border is active
3 If set B/W Video is enabled
7 If clear Vertical Retrace is active
3BFh (W): Hercules Mode Register
bit 0 Set in graphics modes, clear in alpha modes
1 If set the upper 32K at B800h:0 is accessible
Note: This register is only available in Hercules compatibility modes
3C3h (W): Global Enable Register
bit 0 VGA Motherboard Enable if set
Note: this register is used for MicroChannel and motherboard systems, 46E8h
for all other systems.
3C4h index 3 (R/W): Reconfigured Character Map Select
bit 0-2 Offset of character map in plane 2/3 in 8k blocks
3-4 Character map select from plane:
0: plane 2
1: plane 2 if attr. bit 3 set, plane 3 else
2: plane 3 if attr. bit 3 set, plane 2 else
3: plane 3
3C4h index 6 (R/W): PR20 Unlock Paradise Extended Registers (WD90c10+ only)
bit 0-7 Write 48h to this register to unlock the Paradise Extended Sequencer
Registers (3C4h index >7)
3C4h index 7 (R/W): PR21 Display Configuration Status (WD90C10+ Only)
bit 0 (R) Monitor type. TTL if set, Analog if clear. This is the same as
3CEh index 0Fh bit 7
1 (R) EGA emulation if set, VGA if clear. This is the same as 3CEh
index 0Eh bit 1.
2 (R) 6845 compatibility if set. This is the same as 3CEh index 0Ch
bit 6.
3 (R) Color mode if set, mono if clear. This is the same as 3CCh bit 0
4-7 Scratch Pad (Display Configuration)
3C4h index 08h (R/W): PR22 Scratch Pad Register (WD90c10+ only)
bit 0-7 Scratch Pad
3C4h index 09h (R/W): PR23 Scratch Pad Register (WD90c10+ only)
bit 0-7 Scratch Pad
3C4h index 10h (R/W): PR30A Write Buffer and FIFO Control (WD90c11+ only)
bit 0-1 (WD90c24,26,31+?) Display FIFO control. Determines when the FIFO
will request a memory cycle: 0: one level empty, 1: two, 2: three,
3. four
2-3 (WD90c24,26,31+?) FIFO depth. 0: 8 levels, 1: 4 levels,
2,3: 2 levels
4 If set disables 16bit unchained mode (for test only)
5 If set the Display Memory path is 16bit, if clear 32bit
6-7 (WD90c24,26,31+?) Write Buffer Control. 0: Write Buffer is one level
deep, 1: two, 2: three, 3: four
3C4h index 11h (R/W): PR31 System Control Interface (WD90C1x+ Only)
bit 0 16 bit access to CRTC, Graphics Controller and Sequencer Registers
if set
1 16 bit access to Attribute Registers if set and bit 0 set.
If so 3C0h is index and 3C1h is data port.
2 Enable Write buffer if set. Reduces number of wait states for writes
to display memory
3-4 Read Rdy Cntrl. Enhanced speed depending on host bus speed:
0: RDY is inserted at the end of a CPU memory cycle. Used for
Local Bus. Power on default (WD90c24)
1: RDY is inserted 1 MCLK cycle before the end of a CPU memory
cycle. Use for 10MHz or slower ISA systems
2: RDY is inserted 2 MCLK cycles before the end of a CPU memory
cycle.
3: RDY is inserted 1 MCLK cycle after the end of a CPU memory
cycle. Use for 12MHz ISA systems
5 Enhanced text mode operations if set
6 Enhanced operation on blank lines if set. Prevents screen refresh
memory cycles during Vertical Blanking
7 (WD90C1x,24+ Only) RW Offset. If set Bank reg PR0A is used for
read cycles and PR0B for write cycles, else PR0B is used for
A000h-A7FFh and PR0A for A800h-AFFFh.
3C4h index 12h (R/W): PR32 Miscellaneous Control #4 (WD90C1x+ Only)
bit 0 If set use special CPU mapping for 132column text modes ?
1 If set allows reading the registers that are write-only in
compatibility modes (EGA,CGA,MDA registers)
2 (WD90c1x,3x) Clock Select bit 3. Bit 2 is in 3CEh index 0Ch bit 1,
bits 0-1 are in 3C2h/3CCh bits 2-3.
2-3 (WD90c24) Controls the FPUSR0 output pin. 0: set low, 1: set high,
2,3: pin is controlled by 3C4h index 15h bits 0-2
4-5 Controls the FPUSR1 output pin. 0: set low, 1: set high, 2,3: pin is
controlled by 3C4h index 15h bits 3-5
6 Disable Cursor Blinking if set
7 (not WD90c24) Enable External Sync
3C4h index 13h (R/W): PR33A DRAM Timing and Zero Wait State Control
(WD90c1x+ only)
bit 0-1 Length of RAS precharge. 0: 2.5MCLK cycles +d, 1: 3MCLK, 2: 2MCLK,
3: 2.5MCLK
2 If set the CAS cycle starts 1.5 MCLK cycles after RAS low, if clear
2.5 MCLK cycles after RAS low
3-4 CAS timing.
CAS cycle width CAS low CAS high
0: 2 MCLK cycles 1MCLK + d 1MCLK - d
1: 2 MCLK cycles 1MCLK + 2d 1MCLK - 2d
2: 2 MCLK cycles 1.5 MCLK 0.5 MCLK
6-7 Zero Wait State Control. Controls the output on the ZWST pin
0: Reserved, do NOT use
1: Low if the internal write buffer is ready AND the memory
address is decoded.
2: As 1, but also require that MWR is 0
3: As 2, but also low if an I/O write to the VGA occurs.
Note: the time d is 3-7ns for 5V operation, 5-10ns for 3.3V
3C4h index 14h (R/W): PR34A Display Memory Mapping Register (WD90C1x+ only)
bit 0-3 Bits 20-23 of the memory address where the 1MB video buffer is
located if using linear address buffer. For Local Bus versions also
see 2DF2h for the upper 8 address bits.
4-5 Set to enable Linear Frame buffer ???
6 (WD90c33) Bit 8 of PR0A. Bits 0-7 are in 3CEh index 9.
3C4h index 15h (R/W): PR35A FPUSR0,FPUSR1 Output Select (WD90c1x+ only)
bit 0-2 Controls the output on the FPUSR0 pin if 3C4h index 12h bit 3 is set
0: High if an I/O address is decoded
1: High if fetching character attribute from DRAM
2: Low if the internal write buffer is not empty
3: High if a CPU read cycle is occurring
4: Low if a write buffer cycle is occurring
3-5 Controls the output on the FPUSR1 pin if 3C4h index 12h bit 5 is set
0: High if fetching font from DRAM
1: High if fetching graphics data from DRAM
2: High if the internal write buffer is ready
3: High if a CPU write cycle is occurring
4: Low if a CPU write cycle is not caused by the write buffer
3C4h index 16h (R/W): PR45 Video Signature Analyser Control (WD90c24,26)
bit 0 Set to start generation of a signature for a frame. Must be reset
and then set again for the next signature.
1 Clearing this bit initialises the Signature Analyser by preloading
the value 0001h. Must be set before a signature can be generated.
2 If set an all-zero pattern is used as input to the Signature
Analyser rather than the output of the RAMDAC
3 Set to enable access to the Signature Analyser Data registers
(3C4h index 17h,18h)
3C4h index 17h W(R/W): PR45A,B Signature Analyser Data (WD90c24,26)
bit 0-15 Result from Signature Analyser
3C4h index 19h (R/W): PR57 Feature Register I (WD90c24,26)
bit 0 Bank B Enable. If set memory accesses and refresh operations to bank
B display memory is enabled, if clear disabled.
1 Source for REFRESH timing. If set CKIN divided by 3C4h index 34h, if
clear the REFRESH input pin.
2 Panel Power Control. If 3d4h index 32h bit 4 is set this bit
controls the PNLOFF output. 0: PNLOFF high, 1: PNLOFF low
3-4 TFT Dithering Mode Select. Together with 3C4h index 29h bits 2,6 and
3C4h index 21h bit 4 this controls the dithering algorithm.
Index 21h 29h 19h
Bit 4 2 6 3-4
9bit TFT modes:
0 0 0 0 2-Frame Dithering, 27K colors
0 0 0 2 No Dithering, 512 colors
0 0 0 3 Space Dithering, 27K colors
0 1 0 0 2-Frame Dithering, 180K colors
0 1 0 1 2 and 3 Frame Dithering, 256K colors
0 1 0 2 No Dithering, 512 colors
12bit TFT modes:
0 x 1 0 2-Frame Dithering, 226K colors
0 x 1 1 2-Frame Dithering, 226K colors
0 x 1 2 No Dithering, 4K colors
0 x 1 3 Space Dithering, 226K colors
18bit TFT modes:
1 x x 2 No Dithering, 256K colors
All other combinations are invalid
5 If set enables self-refresh when entering Powerdown mode
6 Refresh Clock (REFLCL) Input. Only used in Local Bus mode.
If clear the REFLCL pin provides the refresh clock source (typically
32KHz). This overrides bit 1.
3C4h index 20h (R/W): PR58 Feature Register II (WD90c24,26)
bit 0 Scratch Pad
3C4h index 21h (R/W): PR59 Memory Arbitration Cycle Setup (WD90c24,26)
bit 0-2 Arbitration Cycle Select. Sets the length of the Arbitration Cycle
in units of 160ns (for 25MHz VCLK = 4 VCLK cycles).
3 If set enables Space Dithering in Mode 13h.
4 If set selects 18bit TFT, if clear 9 or 12bit TFT
5 If set the ENDATA output is low, if clear high
3C4h index 24h (R/W): PR62 FR Timing Register (WD90c24,26)
bit 0-7 This value controls the period of the Frame Rate (FR) signal.
Program with 1/4th the number of lines in the FR period.
3C4h index 25h (R/W): PR63 Read/Write FIFO Control (WD90c24)
bit 0 If set enables write operations to the Frame Buffer
1 If set enables read operations from the Frame Buffer
2-7 The time the Frame Buffer can be accessed in MCLKs ?
3C4h index 26h (R/W): PR58A Memory Map Register for BLT Access
in PI/Local Bus (WD90c24)
bit 0-1 Enables Memory Mapping to I/O ports.
0: No I/O Memory Mapping.
1: Map I/O ports 23C0h-23C5h. Writes to A0000h-AFFFFh are decoded
to one of the registers 23C0h-23C7h from the low 3 address bits
3: Map I/O port 23C4h only. Writes to A0000h-AFFFFh are decoded to
register 23C4h
2-3 Select True Color Mode. 0: Normal Palette, 1: 5-6-5 64K True color,
2: 6-5-5 64K True Color, 3: 5-5-5 32K True Color
4 If set data is shifted out of the video FIFO in 16bit chunks.
3C4h index 27h (R/W): PR64 CRT Lock Control II (WD90c24)
bit 0-1 Vertical Expansion Selected (only in 400 line modes):
0,2: No enhanced expansion
1: 3 lines repeated below character
3: One line repeated above character and two lines repeated
below the character
4 Clear to unlock the Horizontal Display End Register (3d4h index 1)
6 Clear to unlock the Vertical Display End Register (3d4h index 12h)
and Overflow Register (3d4h index 7) bits 1 and 6
3C4h index 28h (R/W): PR65 Reserved for future need (WD90c24)
bit 0-7 Reserved
3C4h index 29h (R/W): PR66 Feature Register III (WD90c24)
bit 0-1 Reserved, must be set to 0
2,6 TFT Dithering Mode Select. See 3C4h index 19h bits 3-4.
3 If set VSYNC and HSYNC are forced to in-active low.
4 If set PCLK is forced to inative low. In CRT-only mode BLANK and
VID[0-7] are also forced to inactive low
5 If set LP is the same as HSYNC and FP is the same as VSYNC
7 If set enables Auxiliary Video Extender (AVE) Mode where the
internal RAMDAC is driven from an external source
3C4h index 31h (R/W): PR68 Programmable Clock Selection Register (WD90c24)
bit 0-2 Display Memory Clock Select. In MHz:
0: 55.035 1: 33.111 2: 59.957 3: 37.585
4: 39.822 5: 44.297 6: 47.429 7: 49.219
3-4 Video Dot Clock Select bits 2-3. Bits 0-1 are in 3C2h/3CCh bits 2-3.
The value 2 selects programmed clock via index 32h. In MHz:
0: 29,979 1: 77,408 2: Prog 3: 80,092
4: 25,175 5: 28,322 6: 65,000 7: 36,000
8: 39,822 9: 50,114 10: 42,060 11: 44,297
12: 31,500 13: 35,501 14: 75,166 15: 50,114
3C4h index 32h (R/W): PR69 Programmable VCLK Frequency Register (WD90c24)
bit 0-7 If Video Dot Clock 2 is selected, the Video Dot Clock is calculated
as: (This register) * 0.447443 MHz. Min 25.017MHz, Max 85.014MHz
3C4h index 33h (R/W): PR70 Mixed Voltage Override Register (WD90c24)
bit 0 If set selects 3.3V for AVDD, if clear 5V
1 If set selects 3.3V for MVDD, if clear 5V
2 If set selects 3.3V for FPVDD, if clear 5V
3 If set selects 3.3V for BVDD, if clear 5V
4 If set selects 3.3V for PVDD, if clear 5V
5 If set bits 0-4 determines the Voltage used
3C4h index 34h (R/W): PR71 Programmable Refresh Timing Register (WD90c24)
bit 0-7 If 3C4h index 19h bit 1 is set the CKIN clock (typically 32kHz) is
divided by: ((this register) +1 ) *8
3C4h index 35h (R/W): PR72 Programmable Clock (WD90c24)
bit 4-6 Write 5 to unlock 3C4h index 31h, any other value locks it
3C4h index 36h (R/W): PR73 VGA Status Detect (WD90c24)
bit 0 If set the Core Voltage is 3.3V, if clear 5V
4 If set the FPUSR0 signal is active low, if clear active high
5-6 I/O and Memory Detect. 1: I/O Detection, 2: Memory Detection,
3: I/O & Memory Detection
7 If set enables Status Detect
Note: The WD90c33 appears to use 3C4h index C0h-FFh
3CEh index 9 (R/W): PR0A Address Offset A
bit 0-6 (<WD90c24) Added to bit 12-18 of video memory address if
Bank A selected. (Reads if 3C4h index 11h bit 7 set, A800h-AFFFh
if 3CEh index Bh bit set and 64k config B000h-BFFFh if 128k
config. A000h-AFFFh else).
0-7 (WD90C24,26,3x) same but bit 12-19 rather than 12-18.
3CEh index 0Ah (R/W): PR0B Address Offset B
bit 0-6 (<WD90c24) Added to bit 12-18 of video memory address if
Bank B selected. (Writes if 3C4h index 11h bit 7 set, A000h-A7FFh
if 3CEh index 0Bh bit 3 set and 64k config, A000h-AFFFh if 128k
config).
0-7 (WD90C24,26,3x) Same but bit 12-19 rather than 12-18.
3CEh index 0Bh (R/W): PR1 Memory Size
bit 0 Enable on card ROM if set. Latched on Poweron
1 Select 16 bit ROM access if set. Latched on Poweron
2 Select 16 bit Memory access if set
3 PR0B enabled if set, else use PR0A for both banks
4-5 Memory Map. 0: A000h-BFFFh standard VGA,
1: 1st 256K of a 1MB area, 2: 1st 512K of a 1MB area, 3: 1MB area
For linear mapping 3C4h index 14h (and for Local Bus systems 2DF2h)
select the location of the 1MB buffer in system memory
6-7 Installed memory:
0 256k VGA standard
1 256k PVGA bank switching
2 512k PVGA bank switching
3 1M PVGA bank switching
3CEh index 0Ch (R/W): PR2 Video Configuration
bit 0 Force VCLK (overrides SEQ1 bit 3).
1 Third Clock Select Line VCLK2
This bit appears to be inverted on the WD90c1x and WD90c2x, compared
to the WD90c00 and PVGA1
2,5 Character Map Select/Underline
0 Characters are taken from plane 2
1 do, but characters are underlined if bit 0 of the characters
attribute is set.
2 Characters are taken from plane 3.
3 If bit 3 of the characters attribute is set the character is
taken from plane 3, else from plane 2.
3,4 Character Clock Period Control
0 IBM VGA character Clock (8 or 9 dots wide).
1 7 dots (used for 132 character modes).
2 9 dots
3 10 dots
Selecting 10 dots/character modifies the horizontal PEL panning
register (3C0h index 13h).
6 6845 Compatibility Mode (6845 if set, EGA/VGA if clear).
7 AT&T/M24 Mode Enable, 400 line enable if set
3CEh index 0Dh (R/W): PR3 CRTC Control
bit 0 Lock Vertical Timing (3d4h index 6,(7 bit 0,2,3,5,7),9 bit 5,
(3Dh bit 0,2,3),10h,11h bits 0-3,15h,16h) if set
1 Lock Prevention. Prevent locking through the Vertical Retrace
register (3d4h index 11h bit 7).
2 Multiply Cursor Start, Cursor Stop, Preset Row Scan and Maximum Scan
Line registers by 2
3-4 CRTC Display Start Address bits 16-17. Bits 0-15 are in 3d4h index
0Ch,0Dh. Also bits 16-17 of the Cursor Address (3d4h index 0Eh/0Fh).
5 Lock Horizontal Timing Registers (3d4h index 0-5,17h bit 2) if set
6 Lock HSYNC Polarity (3C2h/3CCh bit 7) if set
7 Lock VSYNC Polarity (3C2h/3CCh bit 6) if set
Note: 3d4h index 0-7 are locked if either 3d4h index 11h bit 7 or bits 0 or 5
of this register is set.
3CEh index 0Eh (R/W): PR4 Video Control
bit 0 Extended 256 color Shift register Control. Configures the video
shift registers for extended 256 color mode if set
1 EGA compatibility. Disables reads of all registers that are
writeonly on the EGA, and of PR0-5 if set.
2 Lock internal Palette and Overscan registers if set
3 Override CGA Enable Video bit. Overrides the CGA "enable video"
bit 3 of 3D8h if set
4 Tri-state Memory Control Outputs if set
5 Tri-state Video (VID0-7) outputs. On the WD90c00 and later also
tri-states the HSYNC, VSYNC and BLNKN
6 (PVGA1A) Tristate HSYNC, VSYNC, BLNKN
(WD90c00 +) Select PCLK=VCLK if set, PCLK = 1/2 VCLK if clear
7 BLNK/Display Enable. If set the BLNKN output supplies PRE-Display
Enable (1 pixel) rather than the BLNKN signal
3CEh index 0Fh (R/W): PR5 General Purpose Status and PR Register
bit 0-2 Extended registers PR0-4 Unlocked if set to 5
3 (R) CNF bit 8. Set for TTL (EGA compatible) display, clear for
Analog (VGA compatible) display.
4 (W) Read protect PR0-4 if set
(R) CNF bit 4
5 (R) CNF bit 5
6 (R) CNF bit 6
7 (R) Multisync if set, fixed frequency else (CNF bit 7 = Switch 1).
3d4h index 29h (R/W): PR10 Unlock PR11-17 Registers (not PVGA1A)
bit 0-2 Write of PR11-18 enabled if set to 5, disabled for all other values
3,7 Read of PR11-18 enabled if bit 3 clear and bit 7 set, any other
value causes reads of PR11-18 to return FFh
3d4h index 2Ah (R/W): PR11 EGA Switches (not PVGA1A)
bit 0 Lock 8/9 Dot Character Clock. Inhibits writes to 3C4h index 1 bit 0
if set.
1 Lock Graphics and Sequencer Screen Control if set
Inhibits write to 3CEh index 5 bit 5-6, 3C4h index 1 bit 2-5 and
3C4h index 3 bit 0-5.
2 Lock Clock Select
3 EGA Emulation on Analog Display
4-7 EGA Switch 1-4. Latched from MD12-15 on reset
4 (WD90c24) CNF17. Together with CNF2 determines bus type:
5-7 (WD90c24) Memory Mode. 4: 2 256Kx16, 5: 1 256Kx16
3d4h index 2Bh (R/W): PR12 Scratch Pad Register (not PVGA1A)
bit 0-7 Reserved
3d4h index 2Ch (R/W): PR13 Interlace H/2 Start (not PVGA1A)
bit 0-7 Interlace H/2 Start. Adjusts Horizontal Sync for interlace.
This register should be programmed with:
(3d4h index 4) - (3d4h index 0 +5)/2 + (3d4h index 5 bits 5-6)
3d4h index 2Dh (R/W): PR14 Interlace H/2 End (not PVGA1A)
bit 0-4 Interlace H/2 End. Adjusts horizontal Sync width. Should be
programmed with the low 5 bits of: (index 2Ch) + (?)
5 Interlace enable if set
6 Vertical Double Scan for EGA on PS/2 Display if set
7 Enable Vertical retrace interrupts if set
3d4h index 2Eh (R/W): PR15 Miscellaneous Control #1 (not PVGA1A)
bit 0 Disable borders if set
1 Select Display Enable Timing. If set BLNKN supplies Display Enable,
if clear BLNKN supplies Pre-Display Enable (one dot-clock prior to
active video). This bit is only active if 3CEh index 0Eh bit 7 is
set
2 Enables page mode addressing in alpha modes if set. Speeds up the
display (I.e. reduces the memory bandwidth used) by utilising the
Fast Page Mode found on all newer DRAM chips. This should be done
for 132 character text modes.
3 Interlace compatible with 8514/A timing if set (should only be set
in interlaced modes). Causes Vertical Sync to be generated from the
trailing edge of non-skewed Horizontal Sync, rather than the leading
edge. Also removes 2 VCLK delays from the default VGA video path.
4 VCLK=MCLK. If set MCLK is used for all video timings.
5 VCLK1,VLKC2 Latched Outputs. If set bits 2 & 3 of 3C2h/3CCh are
output on VCLK1,VCLK2
6 High VCLK. Set if VCLK is much faster than MCLK (more then 50%
faster). Should also be set in all 256color extended modes
7 Enable read of 46E8h if set
3d4h index 2Fh (R/W): PR16 Miscellaneous Control #2 (not PVGA1A)
bit 0 If set prevents writes of the DAC registers (3C6h-3C9h).
1 Standard VGA memory if set (Forces 256K configuration)
2 Enable Page Bit for Odd/Even.
3-4 Bit 16,17 of CRTC Address Counter Offset.
5-6 CRTC Address Counter Width
0= 256k, 1=128K, 2,3=64K
7 If set locks external 46E8h register
3d4h index 30h (R/W): PR17 Miscellaneous Control #3 (not PVGA1A)
bit 0 Maps out ROM at C600h-C67Fh if set
1 (not WD90C00) If set locks the Hercules Compatibility register
(3BFh)
2 (not WD90C00) Enables 64k ROM at C000h-CFFFh if set
3 (not WD90C00) Maps out ROM at C600h-C6FFh if set
4 (not WD90C00) If set PCLK = VCLK/2
5 (not WD90C00) If 3CEh index 0Ch bit 3-4 = 3, this bit selects 6 dot
font if clear, 10dot font if set
3d4h index 31h-37h (R): (WD90C11,24 +)
Contains the text "WD90Cxx" (57h 44h 39h 30h 43h), where xx is model dependent
36h: 37h: Text: Chip:
31h 31h 'WD90C11' WD90C11
32h 34h 'WD90C24' WD90C24
32h 36h 'WD90C26' WD90C26
33h 30h 'WD90C30' WD90C30
33h 31h 'WD90C31' WD90C31
33h 33h 'WD90C33' WD90C33
Note: for the WD90c24 (and probably the 26) these registers are only visible
when the Flat Panel extensions and Mapping Registers are disabled.
(Write 00h to 3d4h index 34h and 35h).
Note: 3d4h index 38h-3Dh appears to hold other chip information like revision
level, however the format is not known yet.
Note: These registers have apparently never been documented by Western Digital
3d4h index 31h (R/W): PR18 Flat Panel Status Register (WD90c2x only)
bit 0-1 LCD Panel Select. 0: Dual Panel LCD, 1: Plasma/EL, 3: Single Panel
LCD Display
2 (W) If set enables TFT Color Interface
4 Together with 3d4h index 3Eh bit 3 selects the Reverse Video mode
for Flat Panel output:
31h bit 4 3Eh bit 3 Effect:
0 0 Normal text and graphics
1 0 Reversed text and graphics
1 1 Reversed text, normal graphics
5 If set selects 256K color palette STN dithering, if clear selects 4K
palette dithering
6 If set enables free running clock for EL, Plasma or TFT panel
7 If set an external RAMDAC is selected and the internal RAMDAC is
disabled, if clear the internal RAMDAC is used.
3d4h index 32h (R/W): PR19 Flat Panel Control 1 (WD90C2x Only)
bit 0-1 Selects the number of VCLK cycles to delay Hsync.
If bit 7 clear: 0: 0, 1: 1, 2: 2, 3: 3
If bit 7 set: 0: 4, 1: 5, 2: 6, 3: 7
2 If set enables Auto-Centering and Vertical Expansion
3 If set Vertical Expansion is selected, if clear Auto-Centering
4 Set if LCD display enabled
5 Set if external display (CRT) enabled
6 Frame Pulse (FP) Timing Select. If set selects ON time during second
horizontal line, if clear during first horizontal line
7 Plasma Panel Interface. If set selects 8bits/2pixel interface, if
clear selects 4bits/pixel interface
3d4h index 33h (R/W): PR1A Flat Panel Control 2 (WD90c2x only)
bit 0-1 Memory Refresh Cycles: 0,2: determined by CRT controller,
1: 1 cycle/line, 3: 2 cycles/line
2 If set Shading Method is Pulse Width Modulation, if clear Frame Rate
Modulation.
3 If set selects 4bit single LCD, if clear selects 8bit single LCD
4,7 Panel Resolution. 0: 640x480, 1: 1280x1024, 2. 1024x768, 3. 800x600
5-6 STN Panel Type. 0: Not a STN Panel, 1: 8bit STN, 3: 16bit STN
3d4h index 34h (R/W): PR1B Flat Panel Unlock Register (WD90C2x Only)
bit 0-2 Write 6 to unlock Shadow registers
5-7 Write 5 to unlock Flat Panel Registers (3d4h index 31h-33h,37h,3Bh,
3Ch,3Eh,3Fh)
Note: Write A6h to unlock all WD90c2x extensions
3d4h index 35h (R/W): PR30 Mapping RAM Unlock (WD90c2x only)
bit 0-7 Write 30h to unlock the Mapping RAM Registers (3d4h index 38h-3Ah).
3d4h index 37h (R/W): PR41 Vertical Expansion Initial Value (WD90c2x only)
bit 0-7 Selects the line to repeat at the top of the frame when Vertical
Expansion is selected.
3d4h index 38h (R/W): PR33 Mapping RAM Address Counter (WD90c2x only)
bit 0-7 The address in Mapping RAM that will be affected by the next access
to index 39h. Any read or write to index 39h will increment this
register.
Note: Should only be access with 8bit I/O operations
3d4h index 39h (R/W): PR34 Mapping RAM Data Register (WD90c2x only)
bit 0-7 The byte in Mapping RAM addressed by index 38h can be accessed here
Note: Should only be access with 8bit I/O operations
3d4h index 3Ah (R/W): PR35 Mapping RAM and Power-Down Control (WD90c2x only)
bit 1 If set enables the NTSC weighting equation: I=0.3R + 0.59G + 0.11B
3 If set bypasses the Mapping RAM, if clear uses Mapping RAM for gray
scale to gray shade mapping
5 If set disables the VGA controller
6 If set (and 3d4h index 3Fh bit 7 is set) enables internal clock
divided by 8
7 If set (and 3d4h index 3Fh bit 7 is set) enters System Power-down
mode - MCLK and VCLK are turned off
3d4h index 3Bh (R/W): PR36 Panel Height Select (WD90c2x only)
bit 0-7 The number of lines (-1) in a single panel.
3d4h index 3Ch (R/W): PR37 Flat Panel Blinking Control (WD90c2x only)
bit 0-2 Cursor Blink Rate. 1: 8 frames on/8 off, 2: 16 on/16 off,
3: 32, 4: 64, 5: 128, 7: no cursor blinking
3-5 Character Blink Rate. 1: 8 frames on/8 off, 2: 16 on/16 off,
3: 32, 4: 64, 5: 128, 7: no cursor blinking
6 Shift Clock Polarity. If set data changes with falling edge of XSCLK
Data should be latched on rising edge. If clear data changes on the
rising edge of XSCLK and should be latched on the falling edge.
7 LCD Latch Pulse (LP) Signal Select. If clear LP is disabled during
Vertical Blanking, if set LP is free running.
3d4h index 3Dh (R/W): PR18A CRTC Vertical Timing Overflow (WD90c30 +)
bit 0 Vertical Total bit 10 (3d4h index 6)
1 Vertical Display Enable bit 10 (3d4h index 12h)
2 Start Vertical Retrace bit 10 (3d4h index 10h).
3 Start Vertical Blank bit 10 (3d4h index 15h).
4 Line Compare bit 10 (3d4h index 18h).
3d4h index 3Eh (R/W): PR39 Color LCD Control (WD90c2x only)
bit 0 LP Polarity Select. If set LP has reverse polarity
1 FP Polarity Select. If set FP has reverse polarity
2 Enable CRT VSYNC and HSYNC if set, if clear the VSYNC and HSYNC
outputs are inactive high
3 Enable Reverse Video. See 3d4h index 31h bit 4
5 Set for Color Panels, clear for Mono Panels.
6 Color LCD Panel Border Select. 0: White, 1: Black
7 Enable LP Border Control. If set generates a special LP pulse to
latch border information
3d4h index 3Eh (R/W): PR18 CRT Vertical Timing (c33 only)
bit 0 Some sort of Vertical timing ?
1 Moves the display up ~32 lines ?? if set. Guess: V Blanking End ?
2 Some sort of timing (looses sync if set)
5 Bit 8 of the Horizontal Total (3d4h index 0)
6 CRTC Display Start Address bit 18. Bits 0-15 are in 3d4h index
0Ch,0Dh and bits 16-17 are in 3CEh index 0Dh bits 3-4.
7 Set if 2MB video memory
3d4h index 3Fh (R/W): PR44 Power-Down and Memory Refresh
Control Register (WD90c2x only)
bit 0-6 Memory Refresh Period
7 Set to enable General Power-down
3d4h index 3Fh (R/W): PR19 Signature Analyser (c33 only ?)
3D8h (W): Color CGA Operation Register
bit 0 If set selects 80x25 text mode, if clear 40x25 text mode
1 Set in graphics modes, clear in text modes.
3 Set in BW modes, clear in color modes
4 If set enables 640x200 BW mode
5 If set enables blinking
Note: this register active in CGA emulation mode only
3D9h (W): CGA Color Select Register
bit 0-3 Each bit controls the behavior of one color:
Bit 0 controls Blue, 1: Green, 2: Red, 3: Intensity
If set the bit has the following effect in each mode:
Alphanumeric mode: Selects the color for the border
320x200 Graphics: Selects the color for border and background
640x200 Graphics: Selects the color for foreground
4 If set enables alternate color set in graphics mode
5 Selects 320x200 color set. 0: backgr, Green, Red, Brown
1: Backgr, Cyan, Magenta, White
Note: this register active in CGA emulation mode only
3DAh (R): CRT Status Register CGA Operation
bit 0 If set blanking or border is active
1 If set Light Pen Latch is set
2 If set Light Pen Switch is closed
3 If set Vertical Retrace is active
Note: this register active in CGA emulation mode only
3DEh (W): AT&T/M24 Register
bit 0 If set selects AT&T/M24 400 line mode, if clear selects 200 line
2 If set selects alternate font in plane 3, if clear standard font in
plane 2
3 If set 16KB Display page starts at BC00h:0, if clear at B800h:0
6 If set the underline attribute selects white underlined foreground,
if clear it selects blue foreground in color text modes
Note: This register is only used in ATT mode (3CEh index 0Ch bit 7 set)
23C0h W(R/W): (WD90c24+ only)
bit 0-7 Selects the register bank at 23C2h.
0: System Control, 1: BitBLT, 2: Cursor, 3: (WD90c33) BitBLT 2
8-11 Register Index (for read operations)
12 If clear the index field is incremented for each read operation of
23C2h/3
13 (R) Invalid register block. Set if the currently selected register
block doesn't exist
Note: The WD90c33 (and possibly the 26) has a different layout of these
registers than the WD90c24 and 31.
23C2h W(R/W): (WD90c24+ only)
bit 0-11 Data to write to the index selected by bits 12-15
12-15 Selects the index the write will go to
Note: The index registers are marked as index a/b where a is the register bank
selected by 23C0h and b is the index from bit 12-15.
23C2h index 0/0 W(R/W): Interrupt Status Register (WD90c24+ only)
bit 0 Set if any interrupt is active
1 Set if Interrupt 1 is active (VGA)
2 Set if Interrupt 2 is active (BITBLT)
3-6 Set if the corresponding interrupt is active
7 Set if any of interrupts 7-10 are active
8 Set if interrupt 7 is active
9 Set if interrupt 8 is active
10 Set if interrupt 9 is active
11 Set if interrupt 10 is active
23C2h index 1/0 W(W): BITBLT Control (WD90c24,31 only)
bit 0-1 BITBLT Source. 0: screen memory, 2: 32bit system I/O address
2-3 Source format. 0: color, 1: mono from color comparators,
2: fixed color (Fill), 3: mono from host
4-5 BitBlt Destination. 0: screen memory, 2: 32bit system I/O address
6 If set Blit source is linear, if clear rectangular
7 If set Blit destination is linear, if clear rectangular
8-9 BitBlt address mode. 0: planar, 1: packed or text mode
10 If set Blit is bottom->top, right->left,
if clear top->bottom, left->right.
11 Activation/status bit. Set this bit to start blit operation
The bit will be cleared when the operation is finished, and can be
read to check when the next operation can be started.
23C2h index 1/0 W(W): Drawing Engine Control 1 (WD90c33 only)
bit 0 Last Pixel Off. Last Pixel not drawn if set
1 Destination Select. If set destination is Host I/O or memory, if
clear it is screen memory.
2 Pattern Enable. Set if the source is an 8x8 pattern
3-4 Source Format. Defines the format of the source data:
0: Source is a Color bitmap
1: Monochrome from Color Comparators
2: Source is fixed color from the Foreground Color Register (index
1/2 and 1/3)
3: Source is monochrome image from the host
5 Source Select. If set source data is from the Host I/O or memory, if
clear it is from the screen memory.
6 Major Row. If set delta Y is larger than delta X (linedraw).
7 Y Direction. If set the blit Y direction is negative (bottom-to-top)
8 X Direction. If set the blit X direction is negative (right-to-left)
9-11 Drawing Mode. 0: Nop, 1: BitBLT, 2: Linestrip, 3: Trapetzoid Fill
Strip, 4: Bresenham Linedraw
23C2h index 1/1 W(W): BITBLT Control (WD90c24,c31 only)
bit 0 Destination transparency if set
1 Reserved, must be 0
2 If set matching pixels are opaque, transparent if clear.
3 Monochrome transparency if set
4-5 BitBLT Pattern Select. 0: no pattern, 1:source is an 8x8 pattern
6 Update destination registers on completion of blit if set
7 Quick start BitBLT when destination register (or source register if
bit 6 is set) is written if set
8 Y direction for line draw. 0: top -> bottom, 1: bottom -> top
9 X or Y Major for line draw. 0: X major, 1: Y major
10 Interrupt when blit completes if set
11 If set enables line drawing, if clear enables BitBLT operation
23C2h index 1/1 W(W): Drawing Engine Control 2 (WD90c33 only)
bit 0-2 Color Expansion Data Bits/Host Write. 2: 2bits/CPU write (16bpp),
3: 4bits/CPU write (8,16bpp)), 4: 8bits/CPU write (4,8,16bpp),
5: 8 or 16 bits/CPU write (4,8,16bpp)
3 Host BitBLT through Memory Port. 0: via I/O, 1: via Memory
6 Command Buffer Empty
7 Monochrome Transparency Source. 0: Off, 1: On
8 Destination Transparency Polarity. 0: Negative, 1: Positive
9 Destination Transparency Enabled if set
10-11 Pixel Depth. 0: 4bits per pixel, 1: 8bpp, 2: 16bpp
23C2h index 1/2 W(R/W): BITBLT Source Low
bit 0-11 Lower 12 bits of the pixel source address
Addresses are in Dwords, 4 bytes for planar modes = 4 pixels, 1 byte
(x4 planes) for planar modes = 8 pixels.
23C2h index 1/2 W(R/W): BITBLT Source Low (WD90c24,c31 only)
bit 0-11 Lower 12 bits of the pixel source address
23C2h index 1/2 W(R/W): X Source (WD90c33 only)
bit 0-11 Starting X coordinate of the source area
23C2h index 1/3 W(R/W): BITBLT Source High (WD90c24,c31 only)
bit 0-8 Upper 9 bits of the pixel source address
23C2h index 1/3 W(R/W): Y Source (WD90c33 only)
bit 0-11 Starting Y coordinate of the source area
23C2h index 1/4 W(R/W): BITBLT Destination Low (WD90c24,c31 only)
bit 0-11 Lower 12 bits of the pixel destination address
Addresses are in Dwords, 4 bytes for planar modes, 1 byte (x4
planes) for planar modes.
23C2h index 1/4 W(R/W): X Destination (WD90c33 only)
bit 0-11 Starting X coordinate of the destination area
23C2h index 1/5 W(R/W): BITBLT Destination High (WD90c24,c31 only)
bit 0-8 Upper 9 bits of the pixel destination address
23C2h index 1/5 W(R/W): Y Destination (WD90c33 only)
bit 0-11 Starting X coordinate of the destination area
23C2h index 1/6 W(R/W): BITBLT Dimension X
bit 0-11 Width of blit area in pixels for BitBLT operations. Length of line
(= max (deltaX, deltaY)) for line draw
23C2h index 1/7 W(R/W): BITBLT Dimension Y
bit 0-11 Height of blit area in scanlines for BitBLT operations.
23C2h index 1/8 W(R/W): BITBLT Row Pitch (WD90c24,c31 only)
bit 0-11 Scanline width at the destination in pixels. This must match with
the Dword system, so the 2 low bits are 0 in packed modes and the 3
low bits are 0 in planar modes.
23C2h index 1/8 W(R/W): Raster Op (WD90c33 only)
bit 8-11 Raster Operation
0 ROP_Zero
1 ROP_And
2 ROP_SAnd
3 ROP_Src
4 ROP_NSad
5 ROP_Dst
6 ROP_Xor
7 ROP_Or
8 ROP_Nor
9 ROP_XNor
10 ROP_NDest
11 ROP_Sond
12 ROP_NSrc
13 ROP_NSod
14 ROP_NAnd
15 ROP_One
23C2h index 1/9 W(W): BITBLT Raster Op (WD90c24,c31 only)
bit 8-11 Raster operation
0 ROP_Zero
1 ROP_And
2 ROP_SAnd
3 ROP_Src
4 ROP_NSad
5 ROP_Dst
6 ROP_Xor
7 ROP_Or
8 ROP_Nor
9 ROP_XNor
10 ROP_NDest
11 ROP_Sond
12 ROP_NSrc
13 ROP_NSod
14 ROP_NAnd
15 ROP_One
23C2h index 1/9 W(R/W): Left Clip (WD90c33 only)
bit 0-11 Left edge of (smallest X coordinate) the clipping rectangle
23C2h index 1/Ah W(R/W): BLT Foreground Color (WD90c24,c31 only)
bit 0-7 BitBLT foreground Color
23C2h index 1/Ah W(R/W): Right Clip (WD90c33 only)
bit 0-11 Left edge of (largest X coordinate) the clipping rectangle
23C2h index 1/Bh W(R/W): BLT Background Color (WD90c24,c31 only)
bit 0-7 BitBLT background color
23C2h index 1/Bh W(R/W): Top Clip (WD90c33 only)
bit 0-11 Top edge of (smallest Y coordinate) the clipping rectangle
23C2h index 1/Ch W(R/W): BLT Transparency Color (WD90c24,c31 only)
bit 0-7 If Color Transparency is enabled (23C2h index 1/1 bit 0 is set) the
pixels in the destination area matching this value will not be
overwritten. 23C2h index 1/0Dh can cause some bits to be ignored in
the comparison
23C2h index 1/Ch W(R/W): Bottom Clip (WD90c33 only)
bit 0-11 Bottom edge (largest Y coordinate) of the clipping rectangle
23C2h index 1/Dh W(R/W): BLT Transparency Mask (WD90c24,c31 only)
bit 0-7 BitBLT Transparency Mask. Each bit set causes the corresponding bit
of the pixel color to be ignored in the transparency comparison
23C2h index 1/Eh W(W): BLT Mask (WD90c24,c31 only)
bit 0-7 Each bit set enables the corresponding plane (0-3) for planar modes,
or bit (0-7) for packed modes
23C2h index 1/Fh (R/W): Drawing Block Index (WD90c33 only)
bit 0-7 Selects the register bank at 23C2h.
0: System Control, 1: BitBLT, 2: Cursor, 3: (WD90c33) BitBLT 2
8-11 Register Index (for read operations)
23C2h index 2/0 W(W): Cursor Control (WD90c24,26,31+ only)
bit 4 (WD90c33) Enhanced Hardware Cursor (24bits per pixel).
If set doubles the cursor horizontally ?
5-7 Cursor Color Mode.
0: Straight monochrome (compatibility)
1: Two color cursor with inversion
2: Two color cursor with special inversion
3: Three color cursor
8 Cursor Plane Protection enabled if set. In planar modes
9-10 Cursor Pattern Type.
0: 2bits per pixel 32x32 cursor
1: 2bits per pixel 64x64 cursor
11 Set to enable hardware cursor
23C2h index 2/1 W(W): Cursor Pattern Address Low (WD90c24,26,31+ only)
bit 0-11 Lower 12 bits of the address of the Cursor Bitmap.
In 256 color modes this is in units of 4 bytes, in planar
modes in bytes. The Upper bits are in index 2.
The address is relative to the Display Start Address
Note: The cursor map data is a 32x32 or 64x64 bitmap with 2 bits per pixel.
In packed modes (256c) the data is stored as 8bits of "A" data followed
by 8bits of "B" data, in planar modes Map 0 and 2 hold the "A" data and
Maps 1 & 3 the corresponding "B" data.
The effect on each pixel depends on the Cursor Color Mode selected by
23C2h index 2/0 bits 5-7:
A: B: Mode 0: Mode 1: Mode 2: Mode 3:
0 0 All 0s Secondary Secondary Secondary
0 1 All 1s Primary Primary Primary
1 0 Transparent Transparent Transparent Transparent
1 1 Inverted Inverted Special Auxilary
Primary is the color in 23C2h index 2/3
Secondary is the color in 23C2h index 2/4
Auxilary is the color in 23C2h index 2/8
Special is the screen data XNOR'ed with the Auxilary color
Inverted is inverted screen data (XOR cursor)
Transparent is the screen data (Invisible cursor)
23C2h index 2/2 W(W): Cursor Pattern Address High (WD90c24,26,31+ only)
bit 0-7 Upper 8 bits of the address of the Cursor Bitmap in the display
memory in units of 4 bytes. The Lower bits are in index 1.
23C2h index 2/3 W(R/W): Cursor Primary Color (WD90c24,31+ only)
bit 0-7 The primary cursor color as an 8bit palette index
23C2h index 2/4 W(R/W): Cursor Secondary Color (WD90c24,31 only)
bit 0-7 The Secondary Color as an 8bit palette index
23C2h index 2/4 W(R/W): Cursor Primary Color mid. byte (WD90c33 only)
bit 0-7 The primary cursor color middle byte
23C2h index 2/5 W(R/W): Cursor Origin (WD90c24,31 only)
bit 0-5 The X hotspot position within the cursor from the left
6-11 The Y hotspot position within the cursor from the top
23C2h index 2/5 W(R/W): Cursor Primary Color high byte (WD90c33 only)
bit 0-7 The primary cursor color high byte
23C2h index 2/6 W(R/W): Cursor X position (WD90c24,31 only)
bit 0-10 The X position of the cursor hotspot in pixels from the left of the
display. In Hi/True color modes this is in bytes, not pixels
23C2h index 2/6 W(R/W): Cursor Secondary Color low byte (WD90c33 only)
bit 0-7 The secondary cursor color low byte
23C2h index 2/7 W(R/W): Cursor Y position (WD90c24,31 only)
bit 0-10 The Y position of the cursor hotspot in scanlines from the top of
the display.
23C2h index 2/7 W(R/W): Cursor Secondary Color middle byte (WD90c33 only)
bit 0-7 The secondary cursor color middle byte
23C2h index 2/8 W(R/W): Cursor Auxiliary Color (WD90c24,31 only)
bit 0-7 The Auxilary cursor color as an 8bit palette index
23C2h index 2/8 W(R/W): Cursor Secondary Color high byte (WD90c33 only)
bit 0-7 The secondary cursor color high byte
23C2h index 2/9 W(R/W): Cursor Auxilliary Color low byte (WD90c33 only)
bit 0-7 The auxilliary cursor color low byte
23C2h index 2/Ah W(R/W): Cursor Auxilliary Color middle byte (WD90c33 only)
bit 0-7 The auxilliary cursor color middle byte
23C2h index 2/Bh W(R/W): Cursor Auxilliary Color high byte (WD90c33 only)
bit 0-7 The auxilliary cursor color high byte
23C2h index 2/Ch W(R/W): Cursor Hotspot (WD90c33 only)
bit 0-5 The X hotspot position within the cursor from the left
6-11 The Y hotspot position within the cursor from the top
23C2h index 2/Dh W(R/W): Cursor X position (WD90c33 only)
bit 0-11 The X position of the cursor in pixels from the left.
In Hi/Truecolor modes this is in units of 3 bytes ?huh?
23C2h index 2/Eh W(R/W): Cursor Y position (WD90c33 only)
bit 0-11 The Y position of the cursor in scanlines from the top.
23C2h index 2/Fh W(R/W): Cursor Register Block/Index (WD90c33 only)
bit 0-7 Selects the register bank at 23C2h.
0: System Control, 1: BitBLT, 2: Cursor, 3: BitBLT 2
8-11 Register Index (for read operations)
23C2h index 3/0 W(R/W): Map Base (WD90c33 only)
bit 0-? Specifies (in units of 4KB) an offset from the start of display
memory that is added to all source and destination addresses.
23C2h index 3/1 W(R/W): Row Pitch (WD90c33 only)
bit 0-11 Scanline width at the destination in pixels.
23C2h index 3/2 W(R/W): Foreground Color 0 (WD90c33 only)
bit 0-7 Low byte of the foreground color
23C2h index 3/3 W(R/W): Foreground Color 1 (WD90c33 only)
bit 0-7 High byte of the foreground color
23C2h index 3/4 W(R/W): Background Color 0 (WD90c33 only)
bit 0-7 Low byte of the background color
23C2h index 3/5 W(R/W): Background Color 1 (WD90c33 only)
bit 0-7 High byte of the background color
23C2h index 3/6 W(R/W): Transparency Color 0 (WD90c33 only)
bit 0-7 Low byte of the transparency color
23C2h index 3/7 W(R/W): Transparency Color 1 (WD90c33 only)
bit 0-7 High byte of the transparency color
23C2h index 3/8 W(R/W): Transparency Mask 0 (WD90c33 only)
bit 0-7 Low byte of the transparency mask
23C2h index 3/9 W(R/W): Transparency Mask 1 (WD90c33 only)
bit 0-7 High byte of the transparency mask
23C2h index 3/Ah W(R/W): Mask Byte Low (WD90c33 only)
bit 0-7 Low byte of the mask. Each bit when set enables writes to that plane
23C2h index 3/Bh W(R/W): Mask Byte High (WD90c33 only)
bit 0-7 High byte of the mask.
23C2h index 3/Fh W(R/W): Drawing Register Block/Index (WD90c33 only)
bit 0-7 Selects the register bank at 23C2h.
0: System Control, 1: BitBLT, 2: Cursor, 3: BitBLT 2
8-11 Register Index (for read operations)
23C4h W(R/W): BitBLT I/O Port
bit 0-15 When the source or destination is set to "system I/O address" the
data must be read or written through this register. The transfer
should always be a multipla of 4 bytes
23C8h W(R/W): Bresenham Constant 1
bit 0-15 For Bresenham line drawing programmed with the constant:
2* min(abs(Xend-Xstart),abs(Yend-Ystart))
23CAh W(R/W): Bresenham Constant 2
bit 0-15 For Bresenham line drawing programmed with the constant:
2* (min(abs(Xend-Xstart),abs(Yend-Ystart))
- max(abs(Xend-Xstart),abs(Yend-Ystart)))
23CCh W(R/W): Bresenham Error Term
bit 0-15 For Bresenham line drawing programmed with the constant:
2*(min(abs(Xend-Xstart),abs(Yend-Ystart)))
- max(abs(Xend-Xstart),abs(Yend-Ystart)) - d
Where d is 0 if Xstart > Xend, -1 if not
23CEh (R/W): Command Buffer (WD90c33)
bit 0-3 (R) Command Buffer Locations. Number of occupied elements in the 8
element command queue. 0: 8 free, 1: 7 free ... 8: No free slots
5 Command Buffer Enabled if set. If disabled the Command Buffer
Locations field follows the Drawing Engine Busy field.
6 Command Buffer Overflow. Set if the buffer has overflowed since it
was last enabled.
7 Drawing Engine Busy if set.
8 Drawing Engine not Busy Interrupt. Write 1 to arm the interrupt
9 Drawing Engine not Busy Interrupt Status. Set if an interrupt is
pending
10 Vertical Retrace Interrupt.
Note: On the '33 this register is used to check if the engine is ready.
Some applications check for bit 0-3 = 0 and some for bits 0-3,7 = 0.
2DF0h (R/W): Local Bus (WD90c24,26, 31 (via the '56), 33)
bit 0-1 Enable Dual Display. 0,1: Disable both, 2: Enable MDA - disable CGA,
3: disable CGA - enable MDA
2 Enable BOFF if clear, disable if set (should be set)
3 VGA Data Path is 16bit if set
4 If set the RAMDAC IOR/IOW cycle is 18 clocks long, if clear (the
default) it is only 9 clocks long
5 If set enables Local Bus Interface, if clear disables it
6 If set use Local Bus RAMDAC, if clear use external RAMDAC
7 If set use Local Bus BIOS, if clear use external BIOS
2DF1h (R/W): (WD90c24,26, 31 (via the '56), 33)
bit 0-1 Memory Read/Write Low Duration.
0: 2 clocks, 1: 3 clocks, 2: 4 clocks, 3: 5 clocks
2-3 Memory Read/Write High Duration.
0: 2 clocks, 1: 3 clocks, 2: 4 clocks, 3: 5 clocks
4-5 IO Read/Write High/Low Duration
0: 2 clocks, 1: 3 clocks, 2: 4 clocks, 3: 5 clocks
6 Enable Wait State. 1 if set, none if clear
2DF2h (R/W): High Address (WD90c24,26, 31 (via the '56), 33)
bit 0-7 High Address A24-31 decode compare
46E8h (R/W): Global Enable Register (AT only)
bit 0-2 BIOS ROM page select (8 pages of 4K each).
3 Adapter VGA enabled if set
4 If set the VGA is in Setup mode, where 102h and 46E8h
are the only ports responding.
Wake Up port at 102h responds only if this bit set.
Note: This register is also addressed at 56E8h, 66E8h and 76E8h.
Register only readable if 3d4h index 2Eh bit 7 set
For MicroChannel and motherboard systems 3C3hj is used instead
Bank Switching:
Bank switching happens by adding the bank register to bit 12-19
of the address, resulting in the window starting on a 4k boundary.
Two different bank registers can be used either as Read/Write
banks (WD90C1x) or as two different windows each 32k/64k big.
Memory:
$C000:$09 string BIOS date
$C000:$35 1 byte BIOS version
$C000:$7D 4 bytes $3ED414756 ('VGA=')
ID Paradise/WD Super VGA Chip set:
old:=rdinx($3CE,$F);
setinx($3CE,$F,$17); {Lock registers}
if not testinx2($3CE,9,$7F) then
begin
modinx($3CE,$F,$17,5); {Unlock again}
if testinx2($3CE,9,$7F) then
begin
old2:=rdinx(base,$29);
modinx(base,$29,$8F,$85); {Unlock WD90Cxx registers}
if not testinx(base,$2B) then 'Paradise PVGA1A'
else begin
wrinx($3C4,6,$48);
if not testinx2($3C4,7,$F0) then 'Western Digital WD90C00'
else if not testinx($3C4,$10) then
begin
if testinx2(base,$31,$68) then 'Western Digital WD90C22'
else if testinx2(base,$31,$90) then 'Western Digital WD90C20A'
else 'Western Digital WD90C20';
wrinx($3d4,$34,$A6);
if (rdinx($3d4,$32) and $20)<>0 then wrinx($3d4,$34,0);
end
else if testinx2($3C4,$14,$F) then
begin
SubVers:=(rdinx(base,$36) shl 8)+rdinx(base,$37);
case SubVers of
$3234:'Western Digital WD90C24'
$3236:'Western Digital WD90C26'
$3330:'Western Digital WD90C30'
$3331:'Western Digital WD90C31'
$3333:'Western Digital WD90C33'
else UNK(Paradise);'
end
else if not testinx2($3C4,$10,4) then 'Western Digital WD90C10'
else 'Western Digital WD90C11';
end;
wrinx($3d4,$29,old2);
end;
wrinx($3CE,$F,old);
Video Modes:
14h T 132 25 16 WD90c33
21h T 132 44 16 WD90c33
41h T 80 34 16
47h T 132 28 16
54h T 132 43 16 (7/8x9)
55h T 132 25 16 (7/8x16)
56h T 132 43 4 (7/8x9)
57h T 132 25 4 (7/8x16)
58h G 800 600 16 PL4
59h G 800 600 2 odd/even **** See note Not on newer boards?
5Ah G 1024 768 2 odd/even **** See note Not on newer boards?
5Bh G 1024 768 4 packed **** See note Not on newer boards?
5Ch G 800 600 256 P8 WD90C11/3x Only
5Dh G 1024 768 16 PL4
5Eh G 640 400 256 P8
5Fh G 640 480 256 P8
60h G 1024 768 256 P8 WD90c3x only
61h G 640 400 32k P15 WD90c31+ only
62h G 640 480 32k P15 WD90c3x only
63h G 800 600 32k P15 WD90c3x only
64h G 1280 1024 16 PL4 WD90c31+ only
66h T 80 50 16 (8x8)
67h T 80 43 16 (8x8)
68h G 320 200 32k P15 WD90c31 only
69h T 132 50 16 (8x8)
6Ah G 800 600 16 PL4
6Ch G 1280 960 16 PL4
6Eh G 640 480 16m P24 WD90c33
71h G 640 400 64k P16 WD90c33
72h G 640 480 16m P24 WD90c31 only (2048 bytes per line)
72h G 640 480 64k P16 WD90c33
73h G 800 600 64k P16 WD90c33
Mode 5Bh 1024x768 4 color.
2 bit per pixel packed mode.
Pixels start in bit 6-7.
Mode 59h 800x600 2 color and
Mode 5Ah 1024x768 2 color.
One bit per pixel odd/even mode
Pixels 0-7 are in plane 0, 8-15 in plane 1.
Bios extensions:
----------10007E-----------------------------
INT 10 - VIDEO - Paradise VGA, AT&T VDC800 - Set Special Mode
AX = 007Eh
BX = horizontal dimension of the desired mode
CX = vertical dimension of the desired mode
Both BX,CX in dots for graph modes, chars for alpha modes
DX = Number of colors desired (0000h for monochrome)
Return: BH = 7Eh if successful (Paradise VGA)
AL = 7Eh if successful (AT&T VDC800)
----------10007F-----------------------------
INT 10 - VIDEO - Paradise .... Extended Mode Set
AX = 007Fh
BH = 00h set VGA operation
BH = 01h set non-VGA operation
color modes (0,1,2,3,4,5,6) will set non-VGA CGA operation
monochrome mode 7 will set non-VGA MDA/Hercules operation
BH = 02h Query mode status
Return: BL = 00h if operating in VGA mode, 01h if non-VGA
mode
CH = total video RAM size in 64k byte units
CL = video RAM used by the current mode
BH = 03h Lock current mode. Allows current mode (VGA or non-VGA) to
survive re-boot.
BH = 04h Set non-VGA MDA/Hercules Mode
BH = 05h Set non-VGA CGA Mode
BH = 06h Set VGA Mono Mode
BH = 07h Set VGA Color Mode
BH = 09h..0Fh Write Paradise Register
BL = New value of PR register
BH = 19h..1Fh Read Paradise Register
Return: BL = Value of register
BH: (Read) BH: (Write) Register
19h 09h PR0A Port 3CEh index 09h
1Ah 0Ah PR0B Port 3CEh index 0Ah
1Bh 0Bh PR1 Port 3CEh index 0Bh
1Ch 0Ch PR2 Port 3CEh index 0Ch
1Dh 0Dh PR3 Port 3CEh index 0Dh
1Eh 0Eh PR4 Port 3CEh index 0Eh
1Fh --- PR5 Port 3CEh index 0Fh
BH = 20h Emulate EGA with Analog Monitor (WD90Cxx Chips Only)
BL=EGA Switches in Bit 0-3
BH = 29h..30h Read Paradise Register (WD90Cxx Chips Only)
Return: BL = Value of register
BH: Register:
29h PR10 Port 3d4h index 29h
2Ah PR11 Port 3d4h index 2Ah
2Bh PR12 Port 3d4h index 2Bh
2Ch PR13 Port 3d4h index 2Ch
2Dh PR14 Port 3d4h index 2Dh
2Eh PR15 Port 3d4h index 2Eh
2Fh PR16 Port 3d4h index 2Fh
30h PR17 Port 3d4h index 30h
BH = 60h
BH = 61h
BH = A5h
BH = A6h
Note: The functions 60h, 61h, A5h and A6h are supported by the 5/14/93 ROM for
the Dell 486D
Return: AL = 7Fh If successful (AT&T VDC600)
BH = 7Fh If valid call (Paradise/Western Digital)
----------106E00-----------------------------
INT 10 - Paradise VGA internal - Get ???
AX = 6E00h
Return: BX = 5744h ('WD') if supported
DH:AH:AL = last three ASCII digits of ROM serial number
CL = ???
CH = ???
----------106E04-----------------------------
INT 10 - Paradise VGA internal - Get Screen Size and ???
AX = 6E04h
Return: BX = screen width (columns)
CX = screen height (lines)
AH = ??? (05h or FFh)
AL = ??? (04h or video mode)
----------106E05-----------------------------
INT 10 - Paradise VGA internal - Set Mode
AX = 6E05h
BL = mode
Note: like AH=00h, AL=BL.
DIP Switch/jumper settings:
VGA Plus, VGA Plus 16, VGA Professional:
Switch 1 Monitor Type. ON: Multi frequency, OFF: Standard VGA
2 VGA Mode Switching Style. ON: PS/2 Style - All modes available on
all monitors, OFF: PC/AT Style - color on color, mono on mono
3 Not used - Set to OFF
4 (Not VGA Plus) 8bit vs 16bit AutoSense. ON: Auto sense 8/16bit
BIOS access, OFF: Force 8bit BIOS access