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'''
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|Gate Array||&7F||Write Only||0||1||-||-||-||-||-||-||-||-||-||-||-||-||-||-
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|PAL||&7F||Write Only||0||(1)||-||-||-||-||-||-||-||-||-||-||-||-||-||-
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|CRTC Select||&BC||Write Only||-||0||-||-||-||-||0||0||-||-||-||-||-||-||-||-
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|CRTC Write||&BD||Write Only||-||0||-||-||-||-||0||1||-||-||-||-||-||-||-||-
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|CRTC Status||&BE||Read Only||-||0||-||-||-||-||1||0||-||-||-||-||-||-||-||-
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|CRTC Read||&BF||Read Only||-||0||-||-||-||-||1||1||-||-||-||-||-||-||-||-
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|ROM select||&DF||Write Only||-||-||0||-||-||-||-||-||-||-||-||-||-||-||-||-
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|Printer port||&EF||Write Only||-||-||-||0||-||-||-||-||-||-||-||-||-||-||-||-
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|PPI Port A||&F4||Read/Write||-||-||-||-||0||-||0||0||-||-||-||-||-||-||-||-
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|PPI Port B||&F5||Read/Write||-||-||-||-||0||-||0||1||-||-||-||-||-||-||-||-
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|PPI Port C||&F6||Read/Write||-||-||-||-||0||-||1||0||-||-||-||-||-||-||-||-
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|PPI Control||&F7||Write Only||-||-||-||-||0||-||1||1||-||-||-||-||-||-||-||-
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|FDC Status||&FB||Read Only||-||-||-||-||-||0||-||1||0||-||-||-||-||-||-||0
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|FDC Data||&FB||Read/Write||-||-||-||-||-||0||-||1||0||-||-||-||-||-||-||1
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|FDC Motor||&FA||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. r1 and r0 mean a bit used to define a register
== I/O Ports ==