Toshiba America Information Systems Inc. ("TAIS") shall not be liable for damages of any kind for use of this information, which is
subject to change without notice. Copyright 1994 TAIS. 4850.DOC Rev. 3 09/24/96 MQC/nmm
Page 1 of 5
T4850CT
(continued)
I/O Port Assignment:
Port Address
From/To
Device/Function
'000' to '01F'
82C37:DMA Controller 1
'020' to '03F'
82C59:PIC 1
'040' to '05F'
82C54:Timer
'060' to '06F'
KBC *6
'070'
NMI Mask Register
'070' to '07F'
RTC
'080' to '09F'
DMA Page Register *3
'0A0' to '0BF'
82C59:PIC2
'0C0' to '0DF'
82C37:DMA Controller 2
'0E0' to '0EF'
Special register *2
'0F0' to '0F7'
Math Coprocessor
'100' to '1EF'
VGA
'1F0' to '1FF'
HDC
'200' to '207'
Game I/O *1
'208' to '20F'
Not Used
'210' to '217'
Expansion Unit *1
'218' to '21F'
Not Used
'220' to '257'
Not Used
'258' to '25F'
Not Used
'260' to '267'
Not Used
'268' to '26F'
Not Used
'270' to '277'
Not Used
'278' to '27F'
Parallel PRT 2 *1
'280' to '2A7'
Not Used
'2A8' to '2AF'
Reserved for EMS *1
'2B0' to 2B7'
Not Used
'2B8' to '2BF'
Reserved for EMS *1
'2C0' to '2DF'
Not Used
'2E0' to '2E7'
Not Used
'2E8' to '2EF'
Reserved for EMS *1
'2F0' to '2F7'
Not Used
'2F8' to '2FF'
Serial Port 2 (COM2)
'300' to '31F'
Prototype Card *1
'320' to '32F'
XT type HDC *1
'330' to '337'
Not Used
'338' to '33F'
Serial Port 3 (COM3) *5
'340' to '377'
Not Used
'378' to '37F'
Parallel PRT 1
'380' to '38F'
SDLC, Bisynchronous 2 *1
'390' to '39F'
Not Used
'3A0' to '3AF'
Bisynchronous 1 *1
'3B0' to '3BF'
MDA, Parallel PRT 3
'3C0' to '3DF'
CGA, EGA, VGA
'3E0' to '3E7'
Not Used
'3E8' to '3EF'
Serial Port 3 (COM3) *5
'3F0' to '3F7'
FDC *4
'3F8' to '3FF'
Serial Port (COM1)
'400' to '47F'
Not Used
'480' to '49F'
DMA Hi-Page Register *3
*1: It is used for expansion cards installed in the Desk Station IV.
*2: These I/O ports are used only for the T4700CS/T4700CT/T4800CT.
*3: 16 x 8 bit read-write registers are assigned to addresses '080' - '08F' and '480' - '49F', however, part of this area is
assigned for DMA page register and DMA high-page register. The area not used for either of these registers can be used for
other purposes. However, if ports '&90' - '&9F' are accessed, '&80' - '&8F' are also accessed. '&81', '&82', '&83', '&87',
'&89', '&8A', '&8B. and '&8F' are used for DMA Page Register /DMA High Page Register. '&80', '&84', '&85', '&86', '&88', '&8C',
'&8D', and '&8E' are used for other purpose or not used.
&=0: DMA Page Register
&=4: DMA High Page Register
*4: I/O Ports '3F6' and '3F7' also, are used for the HDC.
*5: It is used for Desk Station IV's COM3.
*6: I/O ports '060' and '064' are KBC. '061' is system status port.
*7: T4850CT
only.
