Radius XGA2

Thanks to Unal Z. for the original scan, chip IDs, and a copy of the user's manual (switch and jumper settings).

J1 VGA Passthrough
JP1 Reserved
JP2 Reserved
Q1 4.000 MHz xtal
U1-4 MT42C8255DJ-8
U10 inmos IMSG191F 88S
U19 28.322000 MHz osc
U20 inmos IMSG200X-40S
U28 MT5C2568DJ-45
U29 inmos IMSG010JA

U16 PhoenixVIEW VGA-Compatible BIOS, 1985-1991, A 11055
JP5 sets IRQ. From left to right IRQ14, 13, 12, 11, 10 

1. Driver equivalent with the MCA variant.
2. Responds to MCA ID & settings polling.
3. OS/2 2.0 could not identify it, XGARING0.SYS has been fixed later.
4. May require a DOS driver in CONFIG.SYS to assure DMA channel.
5. Aperture disabled per default.

SW1 and SW2

(View the card upside down with the video port to the LEFT)

Note: SW1 and SW2 were made by different manufacturers.
UP, OPEN, and OFF are used interchangeably.

SW2 Settings

1 MEM    UP 16 or 8 bit memory cycles  *
         DN 8 bit memory cycles

2 ROM    UP ROM Enabled
         DN ROM Disabled *

3 IOS    UP 8 or 16 bit I/O cycles *
         DN 8 bit I/O cycles only

4-6 INSTx  x=2,1,0 (XGA Instance)
           4  5  6
Inst0      D  D  D
Inst1      D  D  U
Inst2      D  U  P
Inst3      D  U  U
Inst4      U  D  D
Inst5      U  D  U
Inst6      U  U  D *
Inst7      U  U  U

7-8 DMAx  x=1,0
           7  8
No DMA     D  D
DMA 6      D  U
DMA 7      U  U  *

SW1 Settings

1 Pivot   Reserved, must be UP

2 FPP     Reserved, must be UP

3-4 RSx  x=0,1 ROM Base address
           3  4
C0000h     D  D  *
C8000h     D  U
D0000h     U  D
D8000h     U  U

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Louis F. Ohland, Peter H. Wendt, David L. Beem, William R. Walsh, Tatsuo Sunagawa, Tomáš Slavotínek, Jim Shorney, Tim N. Clarke, Kevin Bowling, and many others.

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