Phoebe (RISC PC II)
Functional Specification
__________________________________________________________________________________
Distribution: COMPANY CONFIDENTIAL
Title: Phoebe Functional Specification
Drawing Number: 0763,000/FS
Issue: E - Developers Only
Date: 11/3/98
Number:
Last Issue: D
__________________________________________________________________________________
1. Introduction 3
2. Overview 4
2.1 Overview of software development 6
2.2 Outline of development testing strategy 6
2.2.1 Hardware 6
2.2.2 Software 6
2.3 External dependencies 6
2.4 Compatibility 7
2.4.1 Summary 7
3. Project deliverables 7
4. Functional Description 8
4.1 Introduction 8
4.2 CPU and RAM 8
4.2.1 Summary: 8
4.3 Additional Processor Expansion 8
4.4 ROM 9
4.4.1 Summary: 9
4.5 IOMDII 9
4.5.1 Summary: 10
4.6 Video 10
4.6.1 Summary: 10
4.7 Sound System and CODEC interface 10
4.7.1 Audio 10
4.7.2 Expansion 11
4.7.3 Joystick interface 11
4.7.4 MIDI Interface 11
4.7.5 Summary 11
4.8 Floppy 11
4.8.1 Summary: 12
4.9 Hard disc and CD ROM/DVD ROM 12
4.9.1 Summary: 12
4.10 Keyboard and mouse 12
4.11 Parallel 12
4.11.1 Hardware Configuration 13
4.12 Serial 13
4.12.1 Hardware Configuration 13
4.13 Expansion interfaces 13
4.13.1 PCI Interface 13
4.13.2 Podule Interface 14
4.14 Power management 14
4.14.1 Power budget 14
5. Mechanical 15
5.1 Enclosure 15
5.2 Packaging 15
6. Conditions of Use 16
6.1 Reliability 16
6.2 Safety 16
6.3 EMC 17
6.3.1 Interference Generation 17
6.3.2 Interference Susceptibility 17
6.4 Environmental 17
6.4.1 Operating 17
6.4.2 Non-operating but unpackaged 17
6.4.3 Shipment and storage 17
7. Manuals 18
8. Service and support 18
9. Expansion Interfaces 19
9.1 Standard Interfaces 19
9.1.1 Monitor Port 19
9.1.2 Keyboard Interface 20
9.1.3 Mouse interface 20
9.1.4 Serial Ports 1 and 2 20
9.1.5 Game port interface 21
9.1.6 Parallel Port 21
9.1.7 Line Input and Output 22
9.2 Front Panel Interfaces 22
9.2.1 Headphone Socket 22
9.2.2 Microphone input 22
10. Change History 22
The functional specification is a detailed specification of the Phoebe (RISC PC II) Project . Phoebe is a development of the existing RISC PC to incorporate as many new developments in the computer world that have occurred since its launch in 1994 e.g. PCI, E-IDE CODECs and SDRAM etc. It is also intended to exploit the performance of the StrongARM processor as much as possible by increasing the speed of the machine from 16 to 64MHz. This specification intends to:
This document includes a product overview followed by a section on each functional area. Where necessary a section will refer to a relevant detailed functional specification. (See section 2.0)
The outline specification of the Phoebe project is described below.
Processor 233Mhz StrongARM on board running at 64MHz I/O
Performance 450k Dhrystones on a monitor supporting 70Hz modes.
Processor expansion card Interface to support upto 4 x 233Mhz StrongARMs on single
processor card) . The card will not form part of this project.
FPA support not available
Floppy drive Single 2MB unformatted
Hard disc 1 T.B.D. size IDE HD with expansion for a further 3.
CD ROM/DVD ROM 32x slot CD ROM fitted as standard. DVD ROM upgrade possible
Total RAM SDRAM support only.
DRAM Expansion upto 512MB of SDRAM with 1 or 2, 32MB SDRAM
DIMMs as standard.
ROM 4MB - board layout allocated for up to 8MB.
VRAM 4MB EDO VRAM fitted to board
Video up to 1024x768 non-interlaced in 32bpp. 1280x1024 24bpp
Drive bays 3 x 5.25", 1 x 3.5" visible bays, and 2 x 3.5" hidden bays
(1 x EIDE drive, CD and 3.5" floppy fitted as standard)
Free Drive Bays 2 x 5.25" visible expansion bays and 1 x 3.5" hidden as standard
PCI interface 4 slots compliant with PCI 2.1 spec (32Mhz 32Bit PCI)
Extended podule slots Backplane connector similar to RISC PC's allowing 3 slots
Case type and volume NLX Mini Tower case, volume = 450x450x190mm (approx.).
Network support 10 and 100 Base-T Ethernet support using a PCI card slot if req.
Parallel port Enhanced bi-directional multimode parallel port as per RISC PC
Serial ports 2 standard PC-AT style ports and IrDA support. Each will support
baud rates up to 460kBaud (the actual performance achieved will depend on software running, user upgrades, screen mode etc.).
ID chip fitted as per RISC PC
Sound system 16 bit digital CD quality provided by Soundblaster compatible
CODEC and VIDC20 sound systems. The Soundblaster sound and Acorn sound are mixed with CD/DVD output
Line input/output Stereo 3.5mm jack sockets on rear
Microphone input Mono 3.5mm jack socket on front of case
Internal speakers Mono
Headphone output Fitted on front, inserting headphone switches off speakers
Joystick 15 way D-type standard PC game port for dual joystick support
MIDI support MIDI input and output at rate of 31.25K baud on game port
PSU 230W NLX standard PSU
For comparison:
RISC PC700: ARM710, 50k Dhrystones in MODE 0, up to 2 IDE devices, 2MB
floppy disc, 4,8 or 16MB RAM, 10,1,2MB VRAM, 800×600×32b
video, 4 single Podule slots, Ethernet network card replacing one
single Podule slot, bi-directional parallel port, serial port, headphone socket
The upgrade will offer in the region of 150-200% of the performance of a StrongARM RISC PC
Figure 1. Phoebe system block diagram
The objective of the operating system development is to extend RISC OS 3.7 to be more compliant with the StrongARM processor and its potential multiprocessor applications within Phoebe. There is a requirement to provide an improved version of the basic desktop environment and improve the existing product. Phoebe requires a revised IOMD and VIDC20 to achieve these objectives and hence the software must be designed to be compatible with these revisions.
The delivered operating system will be in the form of sources and images. Some sources may be suitable for assembly for older platforms than Phoebe, however, the images will be suitable only for the Phoebe platform, and no testing will be done by the project on the suitability for earlier platforms.
The software parts of the Phoebe project will be delivered to the user on ROM and hard disc. The operating system, some basic applications and fonts will be provided in ROM, the remainder on hard disc.
It is not expected that the introduction of new features into the operating system will cause the failure of software written to be compliant with previous style guides.
Some faults found in RISC OS 3.7 have been identified and will be fixed by the Phoebe Software.
Reviews are being held, and will continue to be held, that cover all aspects of the project. Design verification is assured by a series of reviews which cover all aspects of the project. The functional specifications are being reviewed, and various reviews will be held during implementation. These are noted on the project plan. Reviews are made up from peers, relevant people from outside the team, and sometimes an external expert.
In addition to the reviews, the product will be put through the usual hardware quality assurance process, and tested against the environmental requirements and standards given later in this document.
The software faults database and software testing process will also be used to trap hardware faults.
Design reviews and code walkthroughs of software will be held, along with specific documentation reviews. White box test programs for areas being developed will be written to prove the initial functionality of the modules.. Black box test programs will be produced prior to machines being available in line with functional specs. The whole system will be audited in line with all other Acorn products, providing a functional and stable operating system.
Major external dependencies in priority order:
Phoebe will not be designed with the sole intention of being backwards compatible with applications developed for earlier generations of Acorn computers. However programs may work in a single processor mode.
The project will deliver the following:-
The following sections describe the basic functionality of Phoebe. Where further detailed descriptions are required there will be a reference to the relevant Acorn Specification or 3rd party data sheet for the corresponding device.
EC-QPWLC-TE Digital Semiconductor SA-110 Microprocessor Technical Reference
Manual
Phoebe will use a 233MHz StrongARM IC (or greater) fitted on a daughter card for upgradeability, running at a bus clock of 64MHz.
It will support up to 516MB divided into two 256MB SDRAM DIMMs and 4MB EDO VRAM both supplied as standard). The execution space available for each application is limited to 28MB, although it can access all the memory for data, should this be required.
The StrongARM will operate in an asynchronous enhanced mode with a 32bit configuration. Within this configuration, the ARM will almost always be running in 26-bit modes, as most of RISC OS (and all current user programs) will not run in 32-bit modes. Any FIQ-driven device code will be entered in 32-bit mode, and so may have to be modified.
The video system will use EDO VRAM as its display memory. Using EDO VRAM means that high bandwidth screen modes will not affect the machine's speed. The video system will only have a single 4M EDO VRAM fitted to the PCB. EDO VRAM which is not being used for the display will be automatically made available for ordinary program use, but only to a 1MB granularity. The user will not notice this happening.
There will be two expansion routes on the main 64MHz processor bus, each will be allowed to act as local bus master. Control between each processor will be via a combination of 3 bus requests, 3 bus grants and 3 wait signals. Priority between processors may be assigned in a fixed or round robin system. The possible expansion cards are described below, each will require a copy of the standard StrongARM expansion card within their design. Neither form part of this project :-
The operating system will be provided initially in two 42 pin DIL packages giving 4MB or 8MB (via jumper settings) of operating system image. These will be socketed to allow for further user upgrading later. The ROM's specified will be 120ns with a page burst of 50ns. This allows an access speed of upto 8.33MHz and a page access of upto 20MHz - RISC PC ROMs are currently clocked at 5.33MHz.
The ROMs are connected in the system diagram on the 32MHz I/O world bus rather than the 64MHz fast processor bus. This is because the ROMs would not gain from the speed increase as they are inherently slower than the 16Mhz bus currently used. The ROMs will be +5V operation.
IOMDII will support up to two 16MB banks of ROM with individually controllable timing parameters. These are configured as two adjacent areas of 4M x 32 bit Read Only Memory the required one being selected by the physical address line La<24>. Although the area operates as a contiguous 32MB whole, the access timings for each area can be set independently, and are variable from around 220ns downwards in steps of 31.25ns. In addition, support is provided for burst mode ROMs which allow rapid access to sequential addresses controlled by La<2> and La<3>.
In Phoebe only one bank of ROM is used (Bank 0). The motherboard will have two 1M x 16 bit ROM sockets fitted (expandable to 2M x 16 bit via jumpers) providing up to 16MB of ROM space per bank. Two fast page mode 1M x 16bit ROMs will be fitted initially. IOMDII provides two five bit registers to control the individual timing parameters; one for each bank. Three bits control the basic access speed, and two bits control whether burst is used and if so, the burst access speed.
IOMDII (Chandler) is a new memory and I/O controller chip developed for Phoebe. It is designed to work with StrongARM in both single and multiple processor operations, allowing upto 3 separate local bus masters using a modified version of the open bus system. The intercommunication between multiple processors will be achieved by using an internal SRAM area with binary semaphores and circular lists.
The memory and processor bus will run at a 64Mhz speed, the I/O bus will run at 32Mhz. Both will be 32 bit wide. IOMDII's memory interface will work with SDRAM, and VRAM memory in the same system. The I/O system will have a generic interface that will connect to the ROM, Combo, CODEC and Podule interfaces. IOMDII's memory and processor interface will interface to a PCI bridge via an EPLD (for control only) and allow the PCI bridge to run upto 64Mhz, It will also have direct support to the VIDC video controller.
IOMDII contains eight general purpose I/O DMA channels, one sound DMA channel, one cursor DMA channel and one video DMA channel. The general purpose DMA channels may be used for the CODEC, hard drive, parallel port, podule bus and PCI bus interfaces.
Refer to the IOMDII functional specification for full information.
IOMDII is being developed by Acorn using VHDL
The video controller will be a revised version of VIDC20, reducing the silicon from a 1 micron process down to a 0.6 micron process. This will give a 100% performance increase over the existing VIDC20 product. This will enable higher resolution and greater pixel depth than VIDC20.
The new revised "Shrunk" VIDC20 should allow a video system to run with a bandwidth of 400Mbytes using upto a possible 50Mhz VRAM input clock rate and a 64 bit bus, with pixel clock upto 150MHz or above (200Mhz would be required to attain the 1600x1200 screen mode). The basic system maximum is to aim for 1024x768 in 32 bits per pixel using a 4M VRAM system and 1360 x1024 in 16 bits per pixel using a peak allowable bandwidth of 320Mbytes/sec. A possible 1600x1200 may be attained in 16bpp.
See section 9 for pin out information on the screen interface.
AD1816 Analog Semiconductor Single Chip Audio System
The sound system on phoebe will be supplied by two devices; the existing VIDC20 16 bit sound coupled with a CODEC chip. Refer to section 9 for all pin out information.
The VIDC20 sound system will provide 16 bit CD quality sound output via an I2S interface and a serial DAC. This sound will be merged with the sound inputs and output from the CODEC as well as the internal CD ROM sound output. The CODEC has a Soundblaster compatible register set allowing PC sound to be created rather than simulated. The CODEC will support 2 DMA channels for sound in/out and output.
The CODEC gives a stereo line input and output interface to Phoebe for hi-fi quality I/O, along with a microphone input and internal CD audio sound input.
All sound will be 16 bit CD quality audio and will be controlled by volume up/down/mute buttons.
One header will be provided for waveblaster expansion of the CODEC system. This will allow an interface to a MIDI interpreter, synthesiser engine and effects processor along with access to standard MIDI samples including various instruments and percussive sounds.
A 15 way D-type PC game port will be provided for Phoebe by the CODEC IC. This will support two analogue joystick interfaces.
The CODEC also provides an MPU-401 compatible MIDI I/O interface running at a rate of 31.25K baud. It is connected via the 15 way D-type PC style game port. In order to interface directly to MIDI equipment a small amount of external circuitry will be required, this is however the same as all IBM PC compatible MIDI interfaces.
FDC37C67X SMC Enhanced Super I/O Controller with Fast IR
The hardware combo chip (SMC's FDC37C67X) has the same interface as the SMC FDC37C665 used on the RISC PC. The floppy disc interface hardware is integrated into the SMC (Standard Microsystems Corporation) FDC37C67X super I/O Controller device. This device contains a floppy disc controller which is software and register compatible with the Intel 82077, and utilises a '765 disc controller core. For a detailed description refer to SMC's datasheet "FDC37C67X - Super I/O Controller", and the RISC PC floppy drive functional Spec 0197,264/FS (the same signals are available on the FDC37C67X as on the 37C665)
The floppy disc interface connector is the normal 0.1" pitch, 2-row, 34-way box header (Acorn reference number 0803,102).
The power supply for the floppy drive will be a standard 4 pin device(see 0197,000/FS RISC PC Functional Specification for further details)
It is recommended that the cable length between the 34-way interface connector and the disc drive should not exceed 300mm (as per RISC PC).
The main components of the IDE system hardware are; 4 bi-directional data bus buffers, a PAL containing the IDE address decode logic to create the buffer enable signals and DMA controls , and a pair of 40-way IDE interface connectors.
The system will be "ATA-2" / "Enhanced IDE" compliant with a data transfer rate of 16.6Mb capable of PIO mode 4 transfers and possibly DMA mode 2. The system will contain two master/slave pairs allowing upto 4 devices. The devices that may be used are either IDE or ATAPI compliant, hence CD ROM and DVD ROM may be connected. The design differs considerably from the RISC PC in that It is controlled via a PAL device designed in house rather than a COMBO chip. Each master/slave pair is buffered separately and connected to the peripherals via a cable with two 40 way IDC interface connectors.
The interface will support one DMA channel per master/slave pair.
The unit will be fitted with one Slot type 32x CD ROM and one T.B.D. M E-IDE hard disc as standard.
The IDE interface connectors are the normal 0.1" pitch, 2 row, 40-way box headers (Acorn ref.: 0803,103).
The power supply for the hard discs will be a standard 4 way connector (see 0197,000/FS RISC PC Functional Specification for further details)
The Sizes of Hard Disc and speed of the CD ROM supported are not confirmed.
FDC37C67X SMC Enhanced Super I/O Controller with Fast IR
The keyboard and mouse interfaces will both be IBM PC (PS/2 6 pin mini DIN connector) compatible. Both interfaces will be controlled by the Combo IC. Refer to section 9 for pin out information.
FDC37C67X SMC Enhanced Super I/O Controller with Fast IR
The parallel interface will be provided through the SMC FDC37C67X combo chip. This provides hardware handshaking and FIFO giving a minimum speed better than XXK characters per second.
The hardware configuration will be very similar to that of the RISC PC but using IOMDII and the FDC37C67X (refer to 0197,258/FS RISC PC Parallel Hardware Functional Specification and The SMC specification for the FDC37C67X Super I/O controller.
See section 9 for pin out information.
FDC37C67X SMC Enhanced Super I/O Controller with Fast IR
Phoebe will be designed to have two serial ports, however in addition to this there will be IrDA RX and TX signals allowing Infra Red communications. The second serial port may be used at the same time as the IrDA port. The serial port hardware is configurable up to a 460KBaud, but this may not be achievable under the desktop- the speed of which will depend on the screen mode in use, other applications etc. The FDC37C67X I/O chip has two high speed UARTs and 16 byte FIFO's to improve speed of interface. It also contains control circuitry for Modems.
The following new Baud rates will be provided:
The serial port interface hardware is integrated into the Combo IC. This device contains all the necessary hardware and control registers for the serial port with the exception of the interrupt control. All inputs and outputs have EMI filtering and voltage level converters.
Both serial ports will have the same pin out and functionality as the single RISC PC port apart from the increased baud rates. For further information refer to the following specifications , 0197,259/FS RISC PC Serial Hardware Functional Specification and the SMC specification for the FDC37C67X Super I/O controller.
See section 9 for pin out information.
The PCI interface will be implemented using the following major components :- IOMDII, PLX9080, a PCI bridge controller designed to interface between PCI and the Intel i960 I/O controller IC, a custom designed EPLD to interface between the i960 interface and IOMDII, and a PAL to create the arbitration logic across the 4 PCI slots.
The interface logic will fit into the architecture on the 64Mhz open bus, this allows for the possible increase in speed to the 64MHz PCI specification when it becomes available, further to this it allows the system to use the full 132 MB bandwidth of the 32Mhz 32 bit PCI system
The NLX mini tower case will provide 4 PCI slots through the rear of the case, using the riser card.
The interface will conform to PCI functional Specification 2.1. Refer to this document for a more detailed description of the interface itself.
The Podule interface will conform to the Acorn Expansion Card Specification (Acorn part number 0472,200), formerly Podule Electrical Specification. The Extended Acorn Expansion Bus maintains full backward compatibility with the original expansion bus.
The interface will be connected to the 32MHz I/O bus from IOMDII. The signals from IOMDII will have to be modified to interface to the Podule bus. This will be achieved by using a small PAL to bridge between the two.
There will be 3 Podule slots available via a podule backplane in the same manner as the RISC PC. They will be accessed via the rear of the case through 3 punch out holes.
The power supply will be a standard 230W NLX specified PSU (part no. EN-8235941 from Enlight Corp. conforming to both FCC and CE) with the following power rails :-
| Power rail | Tolerance | Current rating |
| +3.3V | 4% | 14A |
| +5V | 5% | 22A |
| -5V | 5% | .5A |
| 5VSB | 5% | 1A |
| +12V | 5% | 6A |
| -12V | 5% | 0.8A |
The table below gives an estimate of the power budget for Phoebe, assuming the following configuration; SDRAM SIMM, 2xEDO RAM SIMM, VRAM SIMM, 3xEIDE drives, CD ROM, floppy , 2x PCI cards, and 2x podules.
| Part | 3.3V (A) | 3.3V (W) | 5.0V (A) | 5V (W) | 12V (A) | 12V (W) | -12V (A) | -12V (W) | Total Power (W) |
| Main PCB | 3.3 | 10.0 | 2.0 | 10.0 | 0.25 | 3.00 | 23.0 | ||
| Floppy | 2.0 | 10.0 | 0.75 | 9.0 | 19.0 | ||||
| Hard Disc (per disc) | 0.5 | 2.5 | 0.50 | 6.0 | (3 off) 25.5 | ||||
| CD/DVD ROM | 0.4 | 2.0 | 0.80 | 9.6 | 11.6 | ||||
| PCI (per card) | 5.0 | 25.0 | 0.5 | 6.0 | (2 off) 62.0 | ||||
| Podule | 1.0 | 5.0 | 0.25 | 3.00 | (2 off) 16.0 | ||||
| Total Power (W) | 20.9 | 104.5 | 4.45 | 54.6 | .25 | 3.00 | 162.1 |
The power budget estimate for the main PCB includes 0.25A for the keyboard supply, 0.1A for the mouse supply, 0.8A for the DIMM module , and allowance in the -12v supply for the provision of a regulated -5v supply to the podule backplane. The 5V supply is regulated down to 2V for the StrongARM core.
The Phoebe case conforms to the NLX motherboard specification release 1.2 © Intel Corp. March 1997. The design allows the motherboard to be replaced simply by removing the bottom of the case. In removing this panel the motherboard is unplugged from a riser card. This riser card has all the connections to the peripherals in the case. The floppy, hard drives, all front panel switches, PCI cards and PSU are connected to the riser. Thus the motherboard can be removed with the minimum of cable disconnections.
The case is a Mini tower design, with the following expansion interfaces :-
3 x 5.25" visible bays (CD's etc)
1 x 3.5" visible bay (floppy drive etc)
2 x 3.5" hidden bays (hard drives etc)
4 PCI slots at rear of case (cards connect to Riser)
3 Podule slots at rear of case (cards connect to backplane card)
Overall dimensions approximately 450mm x 450mm x190mm.
Access to the internals of the case is via removable sides and base. All panels are connected with easily removable clips. The Visible bays are accessed by removing the front panel of the case.
0197,278/FS RISC PC Packaging Functional Specification
Refer to the above specification for details of the packaging style.
Products will be shipped in fully enclosed cardboard based packaging which can be recycled. Provision should be made to enable point of sale sleeves to be added at a later date, as required.
The packaging will be sufficiently robust to complete the following transportation cycle twice - from the manufacturing site to warehouse, to distributor/dealer on to customer and back to repair centre. During this cycle the system will arrive undamaged.
The package will be easy to produce from flat-pack.
The package will be appropriately marked with following as a minimum:
The package will be simple for the user to open.
A typically hard worked machine might see the following usage pattern:
With the above duty cycle, a MTBF of 25,000 hours is to be achieved.
To achieve this operational life routine cleaning by the user and economic servicing and repair may be necessary.
The target failure rate is zero.
External connectors, apart from keyboard and mouse, will have an insertion/extraction cycle of 50 times minimum. The keyboard and mouse will exceed 200 cycles.
Acorn will continue to provide spare parts support for Phoebe for five years from the date of its last manufacture.
With the additional conditions:
Floppy duty cycle (% of POH)
10% Motor on
90% Motor off
The Customer can expect no greater than the following failure rates:
Year after delivery %Units failing
1st year 2%
2nd year 2%
The customer can expect no "dead on arrivals".
For details of MTBF for individual components refer to the specification for that item.
The product will be designed and certified to EN60950 for Europe, CSA 22.2 No.950 and UL1950 for USA and Canada, and AS3260 for Australia and New Zealand. It will therefore display the 'CE' mark as conforming to the Low Voltage Directive (LVD).
From the date of first production, the product shall be tested and certified to EN55022 -Class B, 'Radiated and conducted emissions. The product shall thus be able to display the "CE" mark as conforming to the EMC directive.
Further approvals that may be required are:-
Australia and New Zealand CISPR 22 (This is equivalent to EN55022)
Canada and USA FCC Rules Part 15 - Class B (CFR47 Part15)
From the date of first production output the product will be certified to EN50082-1.
RISC PC Functional Specification
The units must continue to operate under the same conditions as specified for the existing RISC PC.
The units must not be damaged under the same conditions as specified for the existing RISC PC.
The units must not be damaged under the same conditions as specified for the existing RISC PC.
0197,279/FS Phoebe Manuals Functional Specification
The table below details the manuals that will be supplied by the Phoebe project
| Type | Title | Pages | Colours | Style |
| End User manuals | Phoebe Welcome Guide | XXX | 1 | Book |
| RISC OS XXXX User / Apps Guide | XXX | 1 | HTML | |
| Hardware Manuals | Technical Reference Manual | XX+drgs | 1 | A4 ring bound |
| Service Manual | XX + drgs | 1 | Phcopy | |
| Programmer's Manual? | Programmer's Reference Manual | XXX | 1 | Book ? |
| Other Documents | Owner Registration Card | |||
| Release Note | ||||
| Documentation for upgrades |
The product will be guaranteed against defects in manufacture for a period of one year from date of sale to the end user. The product should be capable of supporting a three year extended guarantee period.
In the UK all machines will be sold with an on-site warranty, allowing for a visit by an engineer within 24 hours of end user call. All defective modules will be returned for replacement to the original manufacturing site.
Telephone support will also be provided on all machines sold within the UK. This support will be available during office hours on normal working days.
The following external interfaces are connected directly to the main PCB and exit the box at the bottom rear of the machine.
The monitor port is a standard 15 pin high density D socket as below
| Pin | Signal Name | Notes |
| 1 | RED | |
| 2 | GREEN | |
| 3 | BLUE | |
| 4 | N/C | |
| 5-8 | GND | |
| 9 | +5v | Acorn Specific Signal |
| 10 | GND | |
| 11 | ID[0] | |
| 12 | +12v | Acorn Specific Signal |
| 13 | H/C SYNC | C Sync option is acorn specific |
| 14 | V/C SYNC | C Sync option is acorn specific |
| 15 | N/C |
The following signal ratings apply
| RGB | Source Impedance | 75 Ohms |
| Signal Level | 0 to 0.7v positive into 75 ohms | |
| Horizontal/ Composite (OR)Sync | Source Impedance | 75 Ohms |
| Signal Level | 5v typ. into open circuit (Exceeds minimum TTL thresholds into 1K) | |
| Horizontal/ Composite (OR)Sync | Source Impedance | 75 Ohms |
| Signal Level | 5v typ. into open circuit (Exceeds minimum TTL thresholds into 1K) | |
| ID[0] * - 4k7 pull up to +5V | High | > 2.0v |
| * note ID[3:1] not supported | Low | < 0.8v |
| 5v feed for TV (SCART control via external series resistor) | Maximum current rating | 75mA |
| Fuse protection | 0.8A | |
| +12v (feed for SCART function switch control) | source Impedance | 1K |
| Voltage Output | 11.25 Typ. Into open circuit |
The keyboard 6 pin mini DIN PS2 port is connected as below
| Pin | signal name | Description |
| 1 | KDATA | KDATA Open drain with pull-up. Data signal synchronised with KCLK |
| 2 | NC2 | Not connected |
| 3 | 0V | OV Supply Filtered |
| 4 | Vsupp | 5 volt supply filtered and fused at 2A.Maximum permissible current drain 300mA. |
| 5 | KCLK | Open drain with pull-up. Clock synchronising data transfer between keyboard and host system, generated by the keyboard. |
| 6 | NC6 | Not connected |
The mouse 6 way mini DIN PS2 is connected as below
| Pin | signal name | Description |
| 1 | MSDATA | Mouse DATA Open drain with pull-up. Data signal synchronised with KCLK |
| 2 | NC2 | Not connected |
| 3 | 0V | OV Supply Filtered |
| 4 | Vsupp | 5 volt supply filtered and fused at 2A.Maximum permissible current drain 300mA. |
| 5 | MSCLK | Open drain with pull-up. Clock synchronising data transfer between Mouse and host system, generated by the mouse. |
| 6 | NC6 | Not connected |
The 9 way D-type male connectors are defined as below:-
| Pin | Signal Name | Direction | Function |
| 1 | DCD | Input | Data Carrier Detect |
| 2 | /RXD | Input | Receive Data |
| 3 | /TXD | Output | Transmit Data |
| 4 | DTR | Output | Data Terminal Ready |
| 5 | 0v | Signal Ground | |
| 6 | DSR | Input | Data Set Ready |
| 7 | RTS | Output | Request to send |
| 8 | CTS | Input | Clear to Send |
| 9 | RI | Input | Ring Indicate |
The Pin outs for the Game port 15 way D-type on the motherboard are as below
| Pin | Signal Name | Direction | Function |
| 1 | +5V | Output | PSU Current limited to 200mA |
| 2 | JAB1 | Input | Switch input for Joystick A |
| 3 | JACX | Input | X Co-ordinate for Joystick A |
| 4 | 0V | Output | Ground |
| 5 | 0V | Output | Ground |
| 6 | JACY | Input | Y Co-ordinate for Joystick A |
| 7 | JAB2 | Input | Switch input for Joystick A |
| 8 | +5V | Output | PSU Current limited to 200mA |
| 9 | +5V | Output | PSU Current limited to 200mA |
| 10 | JBB1 | Input | Switch input for Joystick B |
| 11 | JBCX | Input | X Co-ordinate for Joystick A |
| 12 | MIDI_OUT | Output | Sends serial MIDI data out |
| 13 | JBCY | Input | Y Co-ordinate for Joystick A |
| 14 | JBB2 | Input | Switch input for Joystick B |
| 15 | MIDI_IN | Input | Receives serial MIDI data in |
The 25 way D-type female connector is defined as below:-
| Pin | Signal | Type | Active | Function in Printer Mode |
| 1 | /STROBE | OPD | LOW | Indicates that the data at the parallel port is valid. |
| 2-9 | PD0-7 | I/O | 'port data' Bi-directional data bus. Configured as output | |
| 10 | /ACK | IP | LOW | Acknowledge. Indicates that data has been received. |
| 11 | BUSY | IP | HIGH | Indicates that the printer cannot accept additional data. |
| 12 | PE | IP | HIGH | Paper End Indicates that that the printer is out of paper. |
| 13 | SCLT | IP | HIGH | Select Indicates that the printer is selected |
| 14 | /AUTOFD | ODP | LOW | Automatic Feed Causes the printer to automatically add one line |
| 15 | /ERROR | IP | LOW | Indicates the printer has an error condition |
| 16 | /INIT | ODP | LOW | Initialises (Resets) the printer |
| 17 | /SLCTIN | OPD | LOW | Select Input. Selects the printer |
| 18-25 | 0V | Ground |
I = TTL compatible input
O = Output
D = Open drain
P = 4K7 pull-up to VCC
This will be a standard 3.5mm stereo jack socket. The interface will be nominally 1Vrms centred around 2.1 (Vref).
The following ports are connected on the front of the case, in addition to the On/off button, reset button, volume up and down buttons and the infra red panel.
This will be a standard 3.5mm stereo jack socket. The interface will be nominally 1Vrms centred around 2.1 (Vref).
This is a standard 3.5mm mono jack socket. The interface will be nominally 1Vrms centred around 2.1 (Vref)
Issue A 6th December 1996 Initial specification
Issue B 29th May 1997 Second draft, revised layout and more detail
Issue C 8th February 1998 Fitting into NLX mini tower case with 230W
PSU
Issue D 4th March 1998 more detail and updates
Issue E 11th March 1998 tidy up of typos and release for developers only