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ZX Spectrum +2A/2B, +3/3B: Difference between revisions
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==Timings and Contention== | ==Timings and Contention== | ||
The contention and ram timings on the +3 and Black +2 differ significantly from earlier models due to the redesigned [[The Amstrad ASIC|gate array]]. Timing patterns and memory contention are described in detail in the [[Contended_memory#.2B2A_.2F_.2B3|contended memory]] article. | The contention and ram timings on the +3 and Black +2 differ significantly from earlier models due to the redesigned [[The Amstrad ASIC|gate array]]. Timing patterns and memory contention are described in detail in the [[Contended_memory#.2B2A_.2F_.2B3|contended memory]] article. | ||
==Paging== | |||
The memory space is divided into four 16k pages and can be paged in two modes. | |||
====Standard paging mode==== | |||
The 64k of ROM and 128k of RAM can be paged into the memory space as shown in the diagram below: | |||
<!-- table of memory pages with style based on the wikitable class --> | |||
{| style="text-align: center; border-collapse:collapse; margin: 1em 1em 1em 0;" | |||
|- style="height: 5em; background: #f9f9f9;" | |||
| style="width: 5em; background: #f2f2f2; font-style:italic; border: 1px #aaa solid;" | 0xFFFF <br />-<br />0xC000 | |||
| style="width: 5em; border: 1px #aaa solid;" | Bank 0 | |||
| style="width: 5em; border: 1px #aaa solid;" | Bank 1 | |||
| style="width: 5em; border: 1px #aaa solid;" | Bank 2 | |||
| style="width: 5em; border: 1px #aaa solid;" | Bank 3 | |||
| style="width: 5em; border: 1px #aaa solid;" | Bank 4 | |||
| style="width: 5em; border: 1px #aaa solid;" | Bank 5<br />(screen 0) | |||
| style="width: 5em; border: 1px #aaa solid;" | Bank 6 | |||
| style="width: 5em; border: 1px #aaa solid;" | Bank 7 <br />(screen 1) | |||
|- style="height: 5em; background: #f9f9f9;" | |||
| style="width: 5em; background: #f2f2f2; font-style:italic; border: 1px #aaa solid;" | 0xBFFF <br />-<br />0x8000 | |||
| style="border: 1px #aaa solid;" | Bank 2 | |||
|- style="height: 5em; background: #f9f9f9;" | |||
| style="width: 5em; background: #f2f2f2; font-style:italic; border: 1px #aaa solid;" | 0x7FFF <br />-<br />0x4000 | |||
| style="border: 1px #aaa solid;" | Bank 5 | |||
|- style="height: 5em; background: #f9f9f9;" | |||
| style="width: 5em; background: #f2f2f2; font-style:italic; border: 1px #aaa solid;" | 0x3FFF <br />-<br />0x0000 | |||
| style="border: 1px #aaa solid;" | ROM 0 | |||
| style="border: 1px #aaa solid;" | ROM 1 | |||
| style="border: 1px #aaa solid;" | ROM 2 | |||
| style="border: 1px #aaa solid;" | ROM 3 | |||
|} | |||
<!-- end of memory map --> | |||