IBM System/23 Datamaster: Difference between revisions
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=== I/O Ports ===
The Datamaster has a rich set of Intel peripherals which consist of a 8251 USART, 8253 PIT, three 8255 PPI, 8257 DMA, 8259 PIC and 8275 CRTC. All of them, including other devices are accessed using the following ports<ref name=":0" />:
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| 00h-0Fh || 8257 || DMA
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| 20h
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| 21h || 74LS670 || RAM Write Register
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| 22h || 74LS670 || RAM Read Register
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| 23h || 74LS670 || CPU ROS Page Register
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| 2Ch || 8255#1 || Language/Region switches
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| 2Dh || 8255#1 || CE/ROM Update switches, RAM configuration
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| 2Eh || 8255#1 || Unknown; related to memory test 04
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