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ZX Spectrum +2A/2B, +3/3B

798 bytes added, 06:01, 19 November 2012
m
Paging
==Paging==
The memory space is divided into four 16k pages and can be used in two ways; "Standard paging mode" and "Special paging mode".
Paging is controlled by performing I/O writes to ports 0x1ffd and 0x7ffd.
 
The bits are described in the table below:
{| class="wikitable" style="text-align: center;"
|-
! rowspan="2" style="width: 5em;" | Port
! colspan="8" | Bit
|-
! style="width: 5em;" | 7
! style="width: 5em;" | 6
! style="width: 5em;" | 5
! style="width: 5em;" | 4
! style="width: 5em;" | 3
! style="width: 5em;" | 2
! style="width: 5em;" | 1
! style="width: 5em;" | 0
|-
! rowspan="2" style="height: 5em;" | 0x1ffd
| rowspan="2" |   || rowspan="2" |   || rowspan="2" |  
| rowspan="2" | Printer Strobe
| rowspan="2" | Disk Motor
| ROM high || || 0
|-
| colspan="2" | Special paging || 1
|-
! style="height: 5em;" | 0x7ffd
| || || Disable Paging || ROM low || Active Screen || colspan="3" | RAM Bank
|}
====Standard paging mode====

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