This list shows only the internal standard I/O ports, as used in the BIOS ROM of the CPC 464/664/6128 BIOS, and in the AMSDOS ROM of the CPC 664/6128 and DDI-1. For a more complete list, including all Peripherals, see the [[I/O Port Summary|Complete I/O Port Summary]].
== I/O Port Mapping ==
{|{{Prettytable|width: 700px; font-size: 2em;}}
|'''Hardware device'''||'''Address'''||'''Read/Write'''||'''b15'''||'''b14'''||'''b13'''||'''b12'''||'''b11'''||'''b10'''||'''b9'''||'''b8'''||'''b7'''||'''b6'''||'''b5'''||'''b4'''||'''b3'''||'''b2'''||'''b1'''||'''b0'''
|-
|Gate Array||&7F00||Write Only||0||1||-||-||-||-||-||-||-||-||-||-||-||-||-||-
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|PAL||&7F00||Write Only||0||-||-||-||-||-||-||-||-||-||-||-||-||-||-||-
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|CRTC Select||&BC00||Write Only||-||0||-||-||-||-||0||0||-||-||-||-||-||-||-||-
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|CRTC Write||&BD00||Write Only||-||0||-||-||-||-||0||1||-||-||-||-||-||-||-||-
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|CRTC Status||&BE00||Read Only||-||0||-||-||-||-||1||0||-||-||-||-||-||-||-||-
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|CRTC Read||&BF00||Read Only||-||0||-||-||-||-||1||1||-||-||-||-||-||-||-||-
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|ROM select||&DF00||Write Only||-||-||0||-||-||-||-||-||-||-||-||-||-||-||-||-
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|Printer port||&EF00||Write Only||-||-||-||0||-||-||-||-||-||-||-||-||-||-||-||-
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|PPI Port A||&F400||Read/Write||-||-||-||-||0||-||0||0||-||-||-||-||-||-||-||-
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|PPI Port B||&F500||Read/Write||-||-||-||-||0||-||0||1||-||-||-||-||-||-||-||-
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|PPI Port C||&F600||Read/Write||-||-||-||-||0||-||1||0||-||-||-||-||-||-||-||-
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|PPI Control||&F700||Write Only||-||-||-||-||0||-||1||1||-||-||-||-||-||-||-||-
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|FDC Status||&FB7E||Read Only||-||-||-||-||-||0||-||1||0||-||-||-||-||-||-||0
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|FDC Data||&FB7F||Read/Write||-||-||-||-||-||0||-||1||0||-||-||-||-||-||-||1
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|FDC Motor||&FA7E||Write Only||-||-||-||-||-||0||-||0||0||-||-||-||-||-||-||-
|}
0 means the bit must be set to 0 for the hardware device to respond, 1 means the bit must be set to 1 for the hardware device to respond, - means this bit is ignored.
== I/O Ports ==
