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. 4900.DOC Rev. 2 09/24/96 MQC/nmm
Page 11
of 5
T4900CT
(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 *5
'070' NMI Mask Register
'070' to '07F' RTC
'080' to '09F' DMA Page Register *2
'0A0' to '0BF' 82C59:PIC2
'0C0' to '0DF' 82C37:DMA Controller 2
'0E0' to '0EF' Not Used
'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) *4
'340' to '377' Not Used
'378' to '37F' Parallel PRT 1
'388' to '38B' FM Synthesizer
'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) *4
'3F0' to '3F7' FDC *3
'3F8' to '3FF' Serial Port (COM1)
'400' to '47F' Not Used
'480' to '49F' DMA Hi-Page Register *2
'530' to '537' Sound System
'604' to '60B' Sound System
'E80' to 'E87' Sound System
*1: It is used for expansion cards installed in Desk Station IV expansion slots.
*2: 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
*3: I/O Ports '3F6' and '3F7' also, are used for the HDC.
*4: It is used for Desk Station IV's COM3.
*5: I/O ports '060' and '064' are KBC. '061' is system status port.
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