PDS is an acronym for "Programmers Development System" and is a development system made by [[Andy Glaister]].
The system comprised an "[[Apricot PC]]" (an early PC), assembler, debugger, editor, profile, graphics tool and hardware to connect to a target computer.
A company called "Programmers Development Systems Ltd" or "PD Systems" sold it.
The system made it easy to develop for computers like the Amstrad CPC, [[Commodore 64|C64]], [[MSX]], and [[ZX Spectrum]].
The code was written on the PC and transferred through the hardware interface to the target computer.
FBEE PDS [[Z80 PIO]] Port A Control
FBEF PDS [[Z80 PIO]] Port B Control
The handshake bits (in Port FBEDh) are:
0 clock from PC (data transferred on BOTH raising AND falling edges)
1-4 unknown (not connected in spectrum schematic)
5 unknown (something to and/or from PC in spectrum schematic) (could be IRQ)
6 data direction (for 74LS245 transceiver)
7 clock/acknowledge to PC (signals BOTH raising AND falling edges, too)
Note on data direction: This is feature duplicated in hardware, the Z80 PIO itself is bidirectional, so, theoritically, the external 74LS245 transceiver isn't required - it may be there to act as amplifier, or as fuse).
The '''CPC interface''' connects to Expansion Port, and contains a [[Z80 PIO]] chip, and 74LS245, 74LS04, 74LS32 logic chips, and a Reset button. And a 2x8pin connector, for connecting to PC via 16pin flat-cable.
The '''PC interface''' connects to ISA bus, and contains a [[8255 PPI chip]], five logic chips, and two 2x8pin connectors, allowing to connect to up to two slave computers.
The CPC needs to execute [[PDS download source code]], for communicatiing with the debugger, and for loading games CPC software via cable rather than from tape or disc.
''Not 100% sure if above describes the original PC/CPC interfaces - or if that are homebrew remakes (?)''
FBEF - data from PC
Normally, the debug/transfer code isn't included in release versions, however, some CPC release versions do still contain some (unused) code fragments that access some Ports at FBEC-FBEF (in non-Z80 PIO fashion):
* Gremlins (Adventure Soft, UK) (debug I/O code found in spanish Gremlins version)* Last V8* Robin of Sherwood(Adventure Soft, UK)* Seabloodaka Seas of Blood (Adventure Soft, UK)* The Last V8 (Mastertronic)
Unclear if these games were made using an alternate (older or newer) version of the official PDS hardware, or if they were using a similar devkit from another company.
<gallery>
File:NoPicturePDS_Original_Top.gifjpg|Original non-remake hardwareUnit TopFile:PDS_Original_Bottom.jpg|Unit BottomFile:PDS_Original_PCB_Top.jpg|PCB Top File:PDS_Original_PCB_Bottom.jpg|PCB Bottom File:PDS_Original_PCCard_Top.jpg|PC Card Top File:PDS_Original_PCCard_Bottom.jpg|PC Card Bottom
</gallery>
== Manuals ==
* [[Media:The PDS Z80 Manual.pdf]] - Describes Z80 Assembler, Debugger, and Transfer Protocol(1987)
* [[Media:The PDS 6502 Manual.pdf]] - Describes 6502 Assembler, Debugger, and Transfer Protocol
* [[Media:The PDS Editor Manual.pdf]] - Describes the PC side(2nd edition, 1988)
* [[Media:PDS guide early version.pdf]] - Describes the PC side (early version with only 4 pages)
* [[Media:P.D.S. Manual.pdf]] - Describes Assembler directives, Download protocol, Debugger (54 pages) (1987) (OCRed version form worldofspectrum.org)
See DL0,DL1,DL2 source code files for more info on the download protocol.
* http://noname.c64.org/csdb/forums/?roomid=9&topicid=74874#74983
* [http://www.speccy.org/trastero/cosas/JL/PDS/Introduccion.html PDS on speccy.org (in Spanish)]
[[Category:CrossDev]][[Category:Peripherals]]