ZX Spectrum 128: Difference between revisions
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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 | <!-- table of memory pages --> | ||
{| style="text-align: center; border | {| class="wikitable" style="text-align: center; border: none;" | ||
!style="width: 5em;"|0xFFFF <br />-<br />0xC000 | |||
! style="width: 5em | |style="width: 5em;"|Bank 0 | ||
| style="width: 5em | |style="width: 5em;"|Bank 1 | ||
| style="width: 5em | |style="width: 5em;"|Bank 2 | ||
| style="width: 5em | |style="width: 5em;"|Bank 3 | ||
| style="width: 5em | |style="width: 5em;"|Bank 4 | ||
| style="width: 5em | |style="width: 5em;"|Bank 5<br />(screen 0) | ||
| style="width: 5em | |style="width: 5em;"|Bank 6 | ||
| style="width: 5em | |style="width: 5em;"|Bank 7<br />(screen 1) | ||
| style="width: 5em | |- | ||
|- | !0xBFFF <br />-<br />0x8000 | ||
! | |Bank 2 | ||
|colspan="7" style="background: #ffffff; border: 0px none;"| | |||
| | |- | ||
!0x7FFF <br />-<br />0x4000 | |||
|Bank 5<br />(screen 0) | |||
| | |colspan="7" style="background: #ffffff; border: 0px none;"| | ||
|- | |||
| | !0x3FFF <br />-<br />0x0000 | ||
| style="border: | |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 |