![](/images/new-backgrounds/1153249/153249215x1.webp)
System I/O address specifications
I/O address (hex) | System function (shipping configuration) | |
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000 | - 00F | DMA controller no. 1 |
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010 | - 01F | Unused |
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020 | - 021 | Interrupt controller no. 1 |
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022 | - 024 | Opti chipset configuration registers |
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025 | - 03F | Unused |
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02E - 02F | 87334 “Super I/O” configuration for CPU | |
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040 | - 05F | Counter/timer registers |
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044 | - 05F | Unused |
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060 |
| Keyboard controller |
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061 |
| Port B |
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062 | - 063 | Unused |
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064 |
| Keyboard controller |
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065 | - 06F | Unused |
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070 | - 071 | NMI enable/RTC |
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072 | - 07F | Unused |
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080 | - 08F | DMA page registers |
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090 | - 091 | Unused |
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092 |
| Port A |
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093 | - 09F | Unused |
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0A0 - 0A1 | Interrupt controller no. 2 | |
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I/O Address (hex) | System Function (shipping configuration) | |
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0A2 - 0BF | Unused | |
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0C0 - 0DF | DMA controller no. 2 | |
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0E0 - 0EF | Unused | |
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0F0 - 0F1 | Coprocessor busy clear/reset | |
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0F2 - 0FF | Unused | |
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100 | - 16F | Unused |
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170 | - 177 | Secondary fixed disk controller |
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178 | - 1EF | Unused |
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1F0 - 1F7 | Primary fixed disk controller | |
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1F8 - 200 | Unused | |
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201 |
| JoyStick (decoded in ESS1688) |
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202 | - 21F | Unused |
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100 Chapter 6 Specifications