Chrome - an Italian clone of the Spectrum!
Technical Information
Chrome project originates from Speccybob design, but still
speccybob collected only on the TTL chips, a feature of Chrome
are the two chip CPLD Xilinx (matrix, as an alternative. ca.
editor) that not only emulate the Spectrum 48K, but also 128K,
7MGtsYu Z80 and the disk interface. When it is used very little
chip on a compact board.
Each logical device can be completely reprogrammed for a
running board in real time.
The main parameters of Chrome:
Processor: Zilog Z80C 3.58/7.1 MHz clock frequency
RAM: 64K (Spectrum BASIC), 8K ROM rum
RAM: 160k (pages on 16K), 8K ROM frames
Sound: 3 channels, 7 octaves, white noise, stereo, 1 channel
beeper
Input / output: Kempston compatible joystick port extension
I2C interface, a parallel port (printer)
Drives: tape, floppy disk capacity of 800K
Graphics Resolution: 256x192 pixels, 16 colors
RGB Scart output
Krat memory
Chrome is like a memory card in the original 128K Spectrum,
Also added the other two pages of 16K RAM and two pages of ROM.
Pages are installed on port 7FFDh and 1FFDh, perhaps reading
these ports.
Port 7FFDh (read / write)
Bit 0-2 - Pages of RAM (0-7) located at address C000
Bit 3 - Selection of a normal (0) or shadow (1) screen on the
map expression. The normal screen is in bank 5, while
shadow in the bank in July
Bit 4 - Super Select bit ROM
Bit 5 - Latch port 7FFDh
Bit 6-7 - Not ispolzyutsya
Port 1FFDh (read / write)
Bit 0 - If set to 1, with address 0000h are
memory banks 8 and 9 (off ROM)
Bit 1 - Senior Select bit ROM or choice of bank 8 (0) or 9 (1)
if bit0 = 1
Bit 2 - If set to 1 then the bank is located at address 9
4000h, video page is displayed and access can be obtained
chit to address C000h
Bit 3 - Switching the CPU frequency 3.58 MHz (0), 7.1 MHz
(1)
Bit 4 - Disable (1) paged memory when accessing the disk
(Not sure if the original: Disable (1) floppy disk memory
paging.
Ca. Editor)
Bit 5 - If set, then cleaning off by Reset, for
cleaning machine should be turned off (as I understand it,
cleaning
memory. Ca. Editor)
Bit 6 - SCL signal I2C Interface
Bit 7 - SDA signal I2C Interface
FFFFh +------+------+------+------+------+------+------ +------+
| Bank 0 | Bank 1 | Bank 2 | Bank 3 | Bank 4 | Bank 5 |
Bank 6 | Bank 7 |
| | | As | | | as | | |
| | | 8000h | | | 4000h) | | |
| | | | | | Screen | | screen |
C000h +------+------+------+------+------+------+------ +------+
| Bank 2 |
| |
| |
| |
8000h +------+------+
| Bank 5 | Bank 9 |
| | |
| | |
| Screen | |
4000h +------+------+------+------+------+------+------ +
| ROM 0 | ROM 1 | ROM 2 | ROM 3 | Bank 8 | 9 Bank | RAM +
D |
| | | | | | |______| 2000h
| | | | | | | |
| | | | | | | ROM + D |
0000h +------+------+------+------+------+------+------ +
Ritsunok 1. Memory Card Chrome
Joystick Interface
The joystick can be read from the port 1Fh and it is fully
compatible with the Kempston joystick. Of rest buttons
corresponds to 0. Bit 7 read signal Busy printer.
Port 1Fh (read only)
Bit 0 - Right
Bit 1 - Left
Bit 2 - Down
Bit 3 - Top
Bit 4 - Fire
Bit 5 - 0
Bit 6 - 0
Bit 7 - Busy Signal
Programmable sound generator AY-3-8912
AY-3-8912 corresponds to the original Spectrum 128 and
controlled via two ports: Port FFFDh (recording) - Select
Registry muses processor Port FFFDh (Reading) - Reading
Register muses processor Port BFFDh (recording) - Record
Register muses processor
Drive Interface
Disk interface is compatible with + D, developed by Miles
Gordon Technology.
He manages two double-density disk drives with capacities
800K.
Other features + D: parallel printer interface and snapshot
button (magic key) to transfer the dump games to disk or print
images to a printer.
+ D contains additional memory (RAM 8K + 8K ROM), which
connected when the processor reads the instruction code at
addresses 08h, 66h, 028Eh.
Interface ports:
Port E3h (read / write) FDC status / FDC team
Port EBh (read / write) register of the track
Port F3h (read / write) register of sector
Port FBh (read / write) data register
Port E7h (reading) reading from the memory starnitsy + D
Port E7h (record) record in a memory page + D
Port F7h (write) data to the printer (8 bits)
Port EFh (record)
Bit 0 - Select drive 0
Bit 1 - drive select 1
Bit 2-5 - not used
Bit 6 - signal printer Strobe
Bit 7 - Select the side of the disc
Recent changes February 23, 2004.
Opinion Editor
Translation I did myself, it came out, I think is pretty
good, considering the time that I studied French, not
anglitsky. Information taken from an Italian site, the links do
not remember, but if asked, then remember.
There site has photos of prototypes, circuit boards
themselves, kotrolera IBM Claudia, the work of Chrome (toy Atic
Attac loaded with a tape recorder and something else, but with
the SD-Roma in audio format). Terrific impression. Chip
somewhere just five on a small board of two or three will fit
into the housing clave.
Clone of himself fully in line with the original Spektrum128,
Besides the port expansion.
PEOPLE! ANYONE EVER ZASUNET DOMESTIC clone
ALTERA (SCORPIO WITH SMUC AND GMX does not count, they NEED
SELF SCORPIO)
