ZX Spectrum 128
Jump to navigation
Jump to search
- 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 |