Philips P2000T

La première tentative de Philips dans la micro informatique semble remonter au modèle P2000 en 1981 environ. Cette première machine disposait d'un combiné écran/floppie externe. Une version revisitée à usage domestique a rapidement été créée, le P2000T. Cette machine a surtout été diffusée sur le marché hollandais, dans le fief de Philips. Il a connu un certain succès là-bas.

Bien moche et bien mastoc, la machine est assez rigolote. le lecteur de microcassette intégré est vraiment riquiqui, perdu sur la façade !

Passé ce rire hilare, la machine se révèle assez bien construite, et techniquement homogène.

Les autres modèles :

Le P2000M date de 1980. monochrome, il dispose d'un bloc écran floppie 5"1/4. Sa mémoire est extensible à 72Ko et permet l'utilisation de CP/M


photo de basse qualité trouvée sur le oueb

Le P2000C, de 1983, est un transportable à écran cathodique intégré et deux floppies 5"1/4. Il dispose de CP/M et de deux (?) Z80 à 4MHz ! Les informations manquent à son sujet. La machine peux accueillir une carte 8088 pour disposer de MS-DOS. Elle dispose d'un mode graphique 512x256. Un disque dur externe peut même être connectée à cette machine.


photo de basse qualité trouvée sur le oueb

D'autres machines continuent cette gamme. Elles sont beaucoup plus obscures et devient complètement professionnelles. Notons :

Le P2000B, machine CP/M et 5"/14 à base de panier de cartes. Date ?

Le P2500, machine CP/M et 5"/14 à base de panier de cartes. Date ?

Le P3500, machine MP/M, donc multi utilisateurs, avec connections pour des terminaux.

Le 5020, machine monobloc dédiée au traitement de textes. Ecran 15" et bi floppie 5"1/4.

Le 5040, machine plus moderne (écran/uc/clavier) dédiée au traitement de textes. Ecran 15" et bi floppie 5"1/4.

 

Philips P2000T

Première acquisition: Février 2002
Généreux donateur:  

Constructeur: Philips
Modèle: P2000T/00
Année/Prix: 1983 / 1500 florins

CPU: Z80 à 2.5 MHz
RAM/ROM:16 Ko/ 4 Ko (moniteur) et cartouches de 16Ko maximum
Graphisme: 8 couleurs texte : 40x24 en 8 couleurs, gras, clignotant et double hauteur
Mémoire de Masse: Microcassette LDB4401 interne 6000 bauds 42Ko par face

Périphériques:

Cartouche Basic Interpreter 16Ko


Vue du cul et des tripes. Philips est un professionnel de l'électronique, cela se voit (pas avec cette vignette!). La machine est spacieuse et bien construite. Fait curieux, elle est assemblée en Autriche.


philips.gif (503 octets)

Un FAQ en anglais sur l' architecture du P2000

Version 1.1 par Marcel de Kogel (m.dekogel@student.utwente.nl)

This document describes the architecture of the P2000, a home computer from the late 70ies/early 80ies that was extremely popular in Holland. Please note that the information in this document is far from complete, more information may be added in later releases. If anyone is able to contribute to this document, feel free to contact me.

History

1.1 Added keyboard layout specs
1.0 Initial release

There are two models of the P2000 home computer: An M-model and a T-model. The T-model interfaces with a standard colour or black/white television set, whereas the M-model interfaces to a monochrome monitor. The main difference between the two models is found in the video generation.

General Architecture

CPU

The P2000 uses a Zilog Z80 microprocessor running at 2.5MHz

Memories

These memory areas are available:

A 4K8 monitor ROM, which contains the general I/O routines such as the start routine, the keyboard scan routine, cassette interfacing routines, a routine to activate the bell, etc. An application program stored in the program cartridge. This cartridge is inserted onto the CPU board via a slot on the machine. Various programs are available, such as BASIC, Word-processing, etc. The application program's memory can go up to 16K8 8 dynamic memory chips of 16K1 form the system RAM. Part of it is reserved for communication between the application program and the monitor routines, the other part is available for use by the application program. The video memory is different for the T- and M- versions. For the T- version, it is a 2K8 area. It includes the control characters of the teletext character set, while cursor information is also stored there. 80x24 characters can be stored in the first 1920 characters, though only 40x24 characters are displayed at one time. A scroll register is available for scrolling another 40 characters. For the M-version, it consists of two areas: An 2K8 area is used to store the 80x24 characters to be displayed. Another area of 2K4 is used to store the attributes of the characters to be displayed, such as underline, blinking and inverse video. Two more 16K8 dynamic RAM areas can be stored on the extension board. The upper 8K of this area cannot be accessed directly by the CPU and is especially used by disc systems to store part of the operating system.

I/O control

Input and output to external devices is done via I/O ports. Among others, ports are available for scanning the keyboard matrix, serial I/O, the cassette interface, the beep and the floppy-controller.

Interrupts

When the extension board is not used, interrupts are generated via a circuitry on the CPU-board, giving an interrupt every 20ms to scan the key matrix.

When the extension board is used, interrupts are controlled by a programmable interrupt controller providing interrupt addresses for the floppy and the keyboard.

Memory layout

Memory layout is as follows:

0000-0FFF Monitor ROM
1000-4FFF Application program
5000-57FF Video RAM (T-version)
5000-5FFF Video RAM (M-version)
6000-9FFF System RAM
A000-FFFF Extension board

I/O layout

00-09 Keyboard port :

If the keyboard interrupt is enabled, all keyboard matrix rows are connected and reading from either of these ports will give the keyboard status (FF=no key pressed) If the keyboard interrupt is disables, reading one of these ports will read the corresponding keyboard matrix row

10-1F Output port :

Bit Function
0 Cassette write data
1 Cassette write command
2 Cassette rewind
3 Cassette forward
4 Unused
5 Unused
6 Keyboard interrupt enable
7 Printer output

20-2F Input port :

Bit Function
0 Printer input
1 Printer ready
2 Strap N (Daisy/Matrix)
3 Cassette write enabled
4 Cassette in position
5 Begin/End of tape
6 Cassette read clock
7 Cassette read data

The read data is a serial bit pattern in phase encoded format. Read clock is active at the start of every new bit

30-3F Scroll register (T-version only) :

The lower 7 bits of this register hold the index of the first character to be displayed
The upper bit can be used to turn video display on/off (0=display enabled)

50-5F Beeper :

Setting bit 0 of this register will turn on the beeper

70-7F DISAS (M-version only) :

The DISA is activated by setting bit 1 of this register. When the DISA is active, the CPU has the highest priority and video refresh is disabled when the CPU accesses video memory.

Keyboard layout

Y \ X 0 1 2 3 4 5 6 7
0 LEFT 6 up Q 3 5 7 4
1 TAB H Z S D G J F
2 . * SPACE 00 * 0 * # DOWN , RIGHT
3 SHLOCK N < X C B M V
4 CODE Y A W E T U R
5 CLRLN 9 + * - * BACKSP 0 1 -
6 9 * O 8 * 7 * ENTER P 8 @
7 3 * . 2 * 1 * -> / K 2
8 6 * L 5 * 4 * 1/4 ; I :
9 LSHIFT RSHIFT

Keys marked with an asterix (*) are on the numeric keypad

Video processor

The video processor used in the T-model is the SAA5050 teletext character generator. In some versions, it is replaced with a variant with a different character set (e.g. SAA5051 has a German character set). It generates 96 alphanumeric and 64 graphics characters. In addition, there are 32 control characters which determine the nature of display. It's basic input is the 7-bit character data from the teletext page memory. Following are the control codes supported by this device:

00 Unused           10 Unused
01 Alpha Red        11 Graphics Red
02 Alpha Green      12 Graphics Green
03 Alpha Yellow     13 Graphics Yellow
04 Alpha Blue       14 Graphics Blue
05 Alpha Magenta    15 Graphics Magenta
06 Alpha Cyan       16 Graphics Cyan
07 Alpha White*     17 Graphics White
08 Flash            18 Conceal Display
09 Steady*          19 Contiguous Graphics*
0A End Box*         1A Separated Graphics
0B Start Box        1B Unused
0C Normal Height*   1C Black Background
0D Double Height    1D New Background
0E Unused           1E Hold Graphics
0F Unused           1F Release Graphics*

* Default setting

I would like to thank Hans Bus (jbus@hzsbg01.nl.lucent.com) for providing me with a lot of technical information about the P2000