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ZX Spectrum +2A/2B, +3/3B: Difference between revisions

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JEDEC KB
m (Proper name of Spectrum 128)
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{{Infobox computer
{{Infobox computer
| cpu = [[Z80|Z80A]] @ 3.5469MHz
| cpu = [[Z80|Z80A]] @ 3.5469MHz
| rom = 64kB
| rom = 64KB
| ram = 128kB
| ram = 128KB
| rampage = 8×16kB
| rampage = 8×16KB
| manu = Amstrad
| manu = Amstrad
| volume =  
| volume =  
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=====Common hardware specifications=====
=====Common hardware specifications=====
* Processor: Zilog Z80A microprocessor clocked at 3.5469MHz.
* Processor: Zilog Z80A microprocessor clocked at 3.5469MHz.
* ROM: 64kB ROM. 2×32kB EPROM arranged in 4 pages of 16kB.
* ROM: 64KB ROM. 2×32KB EPROM arranged in 4 pages of 16KB.
* RAM: 128kB of Dynamic RAM, arranged in 8 pages of 16kB.
* RAM: 128KB of Dynamic RAM, arranged in 8 pages of 16KB.
* Graphics: 256×192 pixels, 16 colours, attribute based. See [[Spectrum Video Modes]].
* Graphics: 256×192 pixels, 16 colours, attribute based. See [[Spectrum Video Modes]].
* Sound: AY-3-8912 3 channel, 8 octave Programmable Sound Generator and "beeper". Modulated onto video signal.
* Sound: AY-3-8912 3 channel, 8 octave Programmable Sound Generator and "beeper". Modulated onto video signal.
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==Paging==
==Paging==
The memory space is divided into four 16kB pages and can be used in two ways; "Standard paging mode" and "Special paging mode".  
The memory space is divided into four 16KB 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.
Paging is controlled by performing I/O writes to ports 0x1ffd and 0x7ffd.


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====Standard paging mode====
====Standard paging mode====
The 64kB of ROM and 128kB of RAM can be paged into the memory space as shown in the diagram below:  
The 64KB of ROM and 128KB of RAM can be paged into the memory space as shown in the diagram below:  


<!-- table of memory pages -->
<!-- table of memory pages -->