Difference between revisions of "ZX Spectrum 128"

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The memory space of the Spectrum+ 128K is divided into four 16k pages. The 32k of ROM and 128k of RAM can be paged into the memory space as shown in the diagram below:
 
The memory space of the Spectrum+ 128K is divided into four 16k pages. The 32k 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 -->
+
<!-- table of memory pages -->
{| style="text-align: center; border-collapse:collapse; margin: 1em 1em 1em 0;"
+
{| class="wikitable" style="text-align: center; border: none;"
|- style="height: 5em; background: #f9f9f9;"
+
!style="width: 5em;"|0xFFFF <br />-<br />0xC000
! style="width: 5em; background: #f2f2f2; border: 1px #aaa solid; padding: 0.2em;" | 0xFFFF <br />-<br />0xC000
+
|style="width: 5em;"|Bank 0
| style="width: 5em; border: 1px #aaa solid; padding: 0.2em;" | Bank 0
+
|style="width: 5em;"|Bank 1
| style="width: 5em; border: 1px #aaa solid; padding: 0.2em;" | Bank 1
+
|style="width: 5em;"|Bank 2
| style="width: 5em; border: 1px #aaa solid; padding: 0.2em;" | Bank 2  
+
|style="width: 5em;"|Bank 3
| style="width: 5em; border: 1px #aaa solid; padding: 0.2em;" | Bank 3  
+
|style="width: 5em;"|Bank 4
| style="width: 5em; border: 1px #aaa solid; padding: 0.2em;" | Bank 4  
+
|style="width: 5em;"|Bank 5<br />(screen 0)
| style="width: 5em; border: 1px #aaa solid; padding: 0.2em;" | Bank 5<br />(screen 0)  
+
|style="width: 5em;"|Bank 6
| style="width: 5em; border: 1px #aaa solid; padding: 0.2em;" | Bank 6  
+
|style="width: 5em;"|Bank 7<br />(screen 1)
| style="width: 5em; border: 1px #aaa solid; padding: 0.2em;" | Bank 7 <br />(screen 1)
+
|-
|- style="height: 5em; background: #f9f9f9;"
+
!0xBFFF <br />-<br />0x8000
! style="width: 5em; background: #f2f2f2; border: 1px #aaa solid; padding: 0.2em;" | 0xBFFF <br />-<br />0x8000
+
|Bank 2
| style="border: 1px #aaa solid;" | Bank 2
+
|colspan="7" style="background: #ffffff; border: 0px none;"|
|- style="height: 5em; background: #f9f9f9;"
+
|-
! style="width: 5em; background: #f2f2f2; border: 1px #aaa solid; padding: 0.2em;" | 0x7FFF <br />-<br />0x4000
+
!0x7FFF <br />-<br />0x4000
| style="border: 1px #aaa solid;" | Bank 5
+
|Bank 5<br />(screen 0)
|- style="height: 5em; background: #f9f9f9;"
+
|colspan="7" style="background: #ffffff; border: 0px none;"|
! style="width: 5em; background: #f2f2f2; border: 1px #aaa solid; padding: 0.2em;" | 0x3FFF <br />-<br />0x0000
+
|-
| style="border: 1px #aaa solid;" | ROM 0
+
!0x3FFF <br />-<br />0x0000
| style="border: 1px #aaa solid;" | ROM 1
+
|ROM 0||ROM 1
 +
|colspan="6" style="background: #ffffff; border: 0px none;"|
 
|}
 
|}
 
<!-- end of memory map -->
 
<!-- end of memory map -->

Revision as of 00:41, 23 May 2015

  • This article is about the "toastrack" 128K model. For other Spectrum models with 128K of RAM see ZX Spectrum 128K models
Infobox: ZX Spectrum 128
Manufacturer Sinclair Research / Investrónica
Mfg. volume
CPU Z80A @ 3.5469MHz
ROM 32kB
RAM 128kB
as pages 8×16kB
Gfx Res 256×192
Gfx Colours 15 (2 per 8×8 cell)


Hardware

  • Processor: Zilog Z80A microprocessor clocked at 3.5469MHz.
  • ROM: 32KB ROM, arranged in 2 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.
  • Sound: AY-3-8912 3 channel, 8 octave Programmable Sound Generator and "beeper". Modulated onto video signal.
  • Keyboard: 58 plastic keys above a rubber pad and plastic membrane. Optional editor keypad.
  • I/O: Software controlled RS232 serial port. Keypad Port. Tape In (ear) and Tape Out (mic). Expansion I/O port.

Timings

Paging

The memory space of the Spectrum+ 128K is divided into four 16k pages. The 32k of ROM and 128k of RAM can be paged into the memory space as shown in the diagram below:

0xFFFF
-
0xC000
Bank 0 Bank 1 Bank 2 Bank 3 Bank 4 Bank 5
(screen 0)
Bank 6 Bank 7
(screen 1)
0xBFFF
-
0x8000
Bank 2
0x7FFF
-
0x4000
Bank 5
(screen 0)
0x3FFF
-
0x0000
ROM 0 ROM 1

Paging is controlled by performing I/O writes to ports 0x7ffd.

The bits are described in the table below:

Port Bit
7 6 5 4 3 2 1 0
0x7ffd Disable Paging ROM Bank Active Screen RAM Bank

Keypad