PORTIBM PC Portable (uses same BIOS as XT) 03C0-03C1 - EGAEnhanced Graphics Adapter(Enhanced Graphics Adapter) IBMInternational Busiuness Machines's second color video board for the IBMInternational Busiuness Machines PCIBM PC family, capable of a maximum resolution of 640x350 pixels in 16 simultaneous colors of a total of 64 possible colors./VGAVideo Graphics Array(Video Graphics Array) The video adapter introduced with the IBMInternational Busiuness Machines PS/2IBM PS/2, any model series of computers. - ATTRIBUTE CONTROLLER
Range:	PORTIBM PC Portable (uses same BIOS as XT) 03C0h or PORTIBM PC Portable (uses same BIOS as XT) 02C0h (alternate EGAEnhanced Graphics Adapter(Enhanced Graphics Adapter) IBMInternational Busiuness Machines's second color video board for the IBMInternational Busiuness Machines PCIBM PC family, capable of a maximum resolution of 640x350 pixels in 16 simultaneous colors of a total of 64 possible colors.)
SeeAlso: PORTIBM PC Portable (uses same BIOS as XT) 03C2h,PORTIBM PC Portable (uses same BIOS as XT) 03D0h,#P0718

03C0  rW  ATC index/data register
		Every write access to this register will toggle an internal
		  index/data selection flipflop, so that consecutive writes to
		  index & data is possible through this port. To get a defined
		  start condition, each read access to the input status register
		  #1 (3BAh in mono / 3DAh in color) resets the flipflop to load
		  index. If values are changed during the vertical retrace
		  period only no flicker will occur.

		index register (flipflop reset to 'index'): (default 20h)
		  bit7-6: reserved
		  bit5	: 0=CPU(Central Processing Unit) The microprocessor which executes programs on your computer. access (screen dark),
			  1=video access to registers
		  bit4-0: index in ATC (0..31)

		indexed registers in ATC (flipflop set to 'data'): (see #P0662)
03C1  R-  (VGAVideo Graphics Array(Video Graphics Array) The video adapter introduced with the IBMInternational Busiuness Machines PS/2IBM PS/2, any model series of computers.)	ATC index/data read register


(Table P0662)
Values for EGAEnhanced Graphics Adapter(Enhanced Graphics Adapter) IBMInternational Busiuness Machines's second color video board for the IBMInternational Busiuness Machines PCIBM PC family, capable of a maximum resolution of 640x350 pixels in 16 simultaneous colors of a total of 64 possible colors./VGAVideo Graphics Array(Video Graphics Array) The video adapter introduced with the IBMInternational Busiuness Machines PS/2IBM PS/2, any model series of computers. indexed registers in ATC:
 00h-0Fh 16 palette registers (see #P0663)
 10h	mode control register (see #P0664)
 11h	(EGAEnhanced Graphics Adapter(Enhanced Graphics Adapter) IBMInternational Busiuness Machines's second color video board for the IBMInternational Busiuness Machines PCIBM PC family, capable of a maximum resolution of 640x350 pixels in 16 simultaneous colors of a total of 64 possible colors.) overscan color register (see #P0665) (default: 00h)
 11h	(VGAVideo Graphics Array(Video Graphics Array) The video adapter introduced with the IBMInternational Busiuness Machines PS/2IBM PS/2, any model series of computers.) overscan color register (see #P0666) (default: 00h)
 12h	color enable register (see #P0667)
 13h	horizontal pixel panning register
	bit7-4: reserved
	bit3-0: horizontal pixel panning
 14h	(VGAVideo Graphics Array(Video Graphics Array) The video adapter introduced with the IBMInternational Busiuness Machines PS/2IBM PS/2, any model series of computers.) color select register (default: 00h)
	bit7-4: reserved
	bit3  : s-color 7
	bit2  : s-color 6
	bit1  : s-color 5 (only with 16 pages á 16 regs)
	bit0  : s-color 4 (only with 16 pages á 16 regs)
 16h	ET3000, ET4000 only: ATC miscellanenous
	(at least on ET4000 'key' protected)
	This register is also supported by ET3000, but the
	  description is proved for ET4000 only.
	bit7  : bypass the internal palette
		(e.g. for HiColor modes with Sierra RAMDACs)
	bit6  : reserved
	bit5-4: select high resolution / color mode
	bit3-0: reserved
SeeAlso: #P0670,#P0700


Bitfields for EGAEnhanced Graphics Adapter(Enhanced Graphics Adapter) IBMInternational Busiuness Machines's second color video board for the IBMInternational Busiuness Machines PCIBM PC family, capable of a maximum resolution of 640x350 pixels in 16 simultaneous colors of a total of 64 possible colors./VGAVideo Graphics Array(Video Graphics Array) The video adapter introduced with the IBMInternational Busiuness Machines PS/2IBM PS/2, any model series of computers. indexed ATC palette register:
Bit(s)	Description	(Table P0663)
 7-6	reserved
 5	secondary red video
 4	secondary green/intensity video
 3	secondary blue/mono video
 2	primary red video
 1	primary green video
 0	primary blue video
SeeAlso: #P0662


Bitfields for EGAEnhanced Graphics Adapter(Enhanced Graphics Adapter) IBMInternational Busiuness Machines's second color video board for the IBMInternational Busiuness Machines PCIBM PC family, capable of a maximum resolution of 640x350 pixels in 16 simultaneous colors of a total of 64 possible colors./VGAVideo Graphics Array(Video Graphics Array) The video adapter introduced with the IBMInternational Busiuness Machines PS/2IBM PS/2, any model series of computers. ATC mode control register:
Bit(s)	Description	(Table P0664)
 7	(VGAVideo Graphics Array(Video Graphics Array) The video adapter introduced with the IBMInternational Busiuness Machines PS/2IBM PS/2, any model series of computers.) SB/SG select (0=4 pages of 64 regs, 1=16 pages of 16 regs)
 6	(VGAVideo Graphics Array(Video Graphics Array) The video adapter introduced with the IBMInternational Busiuness Machines PS/2IBM PS/2, any model series of computers.) PELCLK/2 (0=4bit color, 1=8bit color)
 5	(VGAVideo Graphics Array(Video Graphics Array) The video adapter introduced with the IBMInternational Busiuness Machines PS/2IBM PS/2, any model series of computers.) enable pixel panning (0=all, 1=up to line compare register value)
 4	reserved
 3	background intensity (0=16 colors, 1=blink)
 2	line graphics enable (0=background, 1=line 8=9)
 1	1=mono, 0=color select
 0	1=graphics, 0=text select
SeeAlso: #P0662


Bitfields for EGAEnhanced Graphics Adapter(Enhanced Graphics Adapter) IBMInternational Busiuness Machines's second color video board for the IBMInternational Busiuness Machines PCIBM PC family, capable of a maximum resolution of 640x350 pixels in 16 simultaneous colors of a total of 64 possible colors. overscan color register:
Bit(s)	Description	(Table P0665)
 7-6	reserved
 5	secondary red (SR)
 4	secondary green (SR) / intensity
 3	secondary blue (SB)
 2	primary red (PR)
 1	primary green (PG)
 0	primary blue (PB)
SeeAlso: #P0662,#P0666


Bitfields for VGAVideo Graphics Array(Video Graphics Array) The video adapter introduced with the IBMInternational Busiuness Machines PS/2IBM PS/2, any model series of computers. overscan color register:
Bit(s)	Description	(Table P0666)
 7	secondary intensity border color (SI)
 6	secondary red (SR)
 5	secondary green (SG)
 4	secondary blue (SB)
 3	intensity border color (PI)
 2	primary red (PR)
 1	primary green (PG)
 0	primary blue (PB)
SeeAlso: #P0662,#P0665


Bitfields for EGAEnhanced Graphics Adapter(Enhanced Graphics Adapter) IBMInternational Busiuness Machines's second color video board for the IBMInternational Busiuness Machines PCIBM PC family, capable of a maximum resolution of 640x350 pixels in 16 simultaneous colors of a total of 64 possible colors./VGAVideo Graphics Array(Video Graphics Array) The video adapter introduced with the IBMInternational Busiuness Machines PS/2IBM PS/2, any model series of computers. color enable register:
Bit(s)	Description	(Table P0667)
 7-6	reserved
 5-4	diagnose / video status select
	EGAEnhanced Graphics Adapter(Enhanced Graphics Adapter) IBMInternational Busiuness Machines's second color video board for the IBMInternational Busiuness Machines PCIBM PC family, capable of a maximum resolution of 640x350 pixels in 16 simultaneous colors of a total of 64 possible colors.:		VGAVideo Graphics Array(Video Graphics Array) The video adapter introduced with the IBMInternational Busiuness Machines PS/2IBM PS/2, any model series of computers., ET4000:
	00b = PR/PB	   PR/PB
	01b = SB/PG	   SG/SB
	10b = SR/SG	   PI/PG
	11b = reserved	   SI/SR
 3	enable plane 3
 2	enable plane 2
 1	enable plane 1
 0	enable plane 0
SeeAlso: #P0662