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Amstrad Serial Interface

4,144 bytes added, 11:43, 11 April 2019
/* Original serial interface (1985) */ Nothing bad about an external PSU!
[[Image:Amstrad RS232.jpg|right|thumb|right|250px|The Pace RS232 interface, as sold by Amstrad]]
[[Amstrad]] released == The two [[RS232]] interfaces, both using the same input/output addresses - and, ultimately, therefore establishing the standard for serial interfaces - but with significantly different hardware.Amstrad Interfaces ==
== Original [[Amstrad]] released two [[RS232]] interfaces, both using the same input/output addresses - and, ultimately, therefore establishing the standard for serial interface ==interfaces.
The main difference between the interfaces is that they contain different firmware, and the older one required an external power supply. === Original serial interface (1985) === Amstrad's first serial interface was one of the original peripherals released for the CPC. It was remarkable (in a bad way) for the necessity for an external, brick-like power supply.
Software was supplied on ROM, mostly comprising utility commands for hobbyists rather than a comms application per se - though there was limited terminal emulation for connecting to the then-popular [[Prestel]] service]. The original, UK version included commands for file transfer entitled |SUCK and |BLOW, which used a proprietary Amstrad format similar to [[XModem]]-1k but, annoyingly, subtly incompatible. These commands were reputedly renamed for the US edition to avoid causing offence.
 
The French company [[M.E.R.C.I.]] sold a custom version of this interface, replacing the original 8k ROM with an 16k Rom adding a [http://en.wikipedia.org/wiki/Minitel minitel] emulator.
Because of the external power supply and the poor quality of the software, this model failed to establish itself as the "standard" serial interface in the way that (say) the [[DDI-1]] did for disc drives. This allowed other serial interfaces to flourish, such as those sold by [[Cirkit]] and [[KDS]].
=== Pace serial interface (1986) ===
As a result, Amstrad dropped their original design and instead chose to remanufacture a [[PacePACE]] design. This included significantly improved hardware (a more compact interface thanks to SMD components and no external PSU) and vastly superior software. However, this redesign also reduced the quality of RS232 signalling by using 0V/5V output voltage instead of -12V/12V.
The software was a ROM version of Pace's the [[Commstar]] terminal utility, from [[CommstarHoneySoft]]. This was a user-friendly program with standard [[XModem]] file transfer functions. However, one foolish design decision was the idea of using a 24x80 screen with a single-line status display - though presenting a good user interface, this forced the use of software rather than hardware scrolling, making the interface unusable for terminal emulation at any speed above 2400 baud.
Like the original interface, the The Amstrad/Pace design used an 8250 version was announced on [[UART:File:ACU8612006.jpg|Amstrad Computer User, Dec 1986, page 6]] chip, which was reliable up to 9600 baud and could sometimes function at faster speeds. The possibility has been discussed of replacing this with a pin-compatible 16550 and gaining even faster transfer speedsA review occured in Amstrad Computer User, but this is not believed to have been testedApril 1987, pages 46 and 47.
== Alternative software I/O Ports ==
The limitations of Here are the Commstar software, and the desire to use more recently developed file transfer protocols I/O Ports (such as [[XModem]]-1k, [[YModem]] same for original and [[ZModem]]Pace version) meant that many users chose to use their Amstrad serial interface with third-party software. This included:
* FADCh Amstrad RS232 [[AnsitermZ80-DART/Z80-SIO chip|Z8470 (Z80 DART)]] Channel A Data (R/W) FADDh Amstrad RS232 [[Z80- a fast AMSDOS utility DART/Z80-SIO chip|Z8470 (also known as ANSI.ARCZ80 DART)]] Channel A Control/Status (R/W)* FADEh Amstrad RS232 [[Charley's Comms ROMZ80-DART/Z80-SIO chip|Z8470 (Z80 DART)]] Channel B Data (R/W) FADFh Amstrad RS232 [[Z80- sideways ROM capable of 4800 baud terminal emulationDART/Z80-SIO chip|Z8470 (Z80 DART)]] Channel B Control/Status (R/W)* FBDCh Amstrad RS232 [[ZMP8253 chip|8253]] - ZModem file transfer under CPBaudrate Timer 0 Channel A TX Clock (R/MW) FBDDh Amstrad RS232 [[8253 chip|8253]] Baudrate Timer 1 Channel A RX Clock (R/W) FBDEh Amstrad RS232 [[8253 chip|8253]] Baudrate Timer 2 Channel B RX/TX Clock (R/W) FBDFh Amstrad RS232 [[8253 chip|8253]] Baudrate Timer 0-2 Control Registers (W)
A vast range of comms software was available for [[CP/M]], including [[bulletin board]] hosts, offline readers Note: Some interfaces might use a Z80 SIO (notably [[CRR]] - CP/M Read and Replywhich is backwards compatible to the Z80 DART), and many terminals.
== Technical specs ==For details on the I/O ports, see:
This * [http:[Z80-DART//wwwZ80-SIO chip]]* [[8253 chip]] Although the Z80-DART (and Z80-SIO) support two channels, most or all existing CPC interfaces seem to use only one channel.systemed.net == CP/pcwM == The I/cps8256O ports are directly supported under CP/M (without needing additional drivers).html webpage about Like many CP/M functions, the CPS8256] functions are located in the AMSDOS ROM (not on the Amstrad serial interface for the PCWCP/M disc) also includes some useful CPC information . These functions are using hardcoded RAM addresses, which conflict with the BASIC memory map, so they can be used only under CP/M, not under BASIC. == Alternative software == The limitations of the [[Commstar]] software, and the desire to use more recently developed file transfer protocols (such as [[XModem]]-1k, [[YModem]] and may be worth converting in due course[[ZModem]])meant that many users chose to use their Amstrad serial interface with third-party software.
== Pictures ==
<gallery caption="Amstrad 's older original serial interface">Image:amstrad RS232C.jpg|The original, flawed Amstrad serial interfaceImage:Amstrad rs232 1.jpg|The original Amstrad serial interfaceImage:Amstrad rs232 2.jpg|The original Amstrad serial interfaceImage:Amstrad rs232 power1.jpg|The original powersupply that came with the interfaceImage:AmstradRS232PSU_Rating.jpg|The original powersupply ratingImage:Amstrad RS232C Box.jpg|Old interface, boxedImage:Amstrad RS232C Device.jpg|Old interface with PSUImage:Amstrad RS232C PCB.jpg|Old interface, PCB
</gallery>
<gallery caption="Amstrad's original interface 300dpi scans">Image:Amstrad_RS232C_Top_EN.jpg|Interface Top (English)Image:Amstrad_RS232C_Top_FR.jpg|Interface Top (French)Image:Amstrad_RS232C_PCB_Top.jpg|Interface PCB TopImage:Amstrad_RS232C_PCB_Bottom.jpg|Interface PCB Bottom</gallery> <gallery caption="Amstrad's newer Pace serial interface">File:Amstrad RS232.jpg|Newer Amstrad/Pace InterfaceFile:Amstrad_RS232_Pace_Interface.jpg|Pace InterfaceFile:Amstrad_RS232_Pace_PCB_Top.jpg|PCB TopFile:Amstrad_RS232_Pace_PCB_Bottom.jpg|PCB BottomFile:ACU8701002.jpg|Advert (ACU, January 1987)</gallery> == Schematic and More (CPS8256) == Below shows schematic and pictures for the CPS8256 Serial Interface (for the Amstrad PCW, aka Schneider Joyce), ie. it is ''not'' really CPC hardware, however, the CPC interface should use a similar design (the major difference is probably that the CPC version contains a BIOS ROM, but no Centronics port). Credits: The gif and jpg's are from [http://www.z80.eu/cps8256.html www.z80.eu]. <gallery caption="CPS8256">File:Cps8256-circuit.gif|SchematicFile:Cps8256-case-lower.jpg|Case lower sideFile:Cps8256-case-upper.jpg|Case upper sideFile:Cps8256-pcb-component-side.jpg|Component sideFile:Cps8256-pcb-component-noadd2.jpg|Without componentsFile:Cps8256-pcb-layer-side.jpg|Solder sideFile:Cps8256-additional-pcb-side.jpg|Voltage converterFile:Cps8256-additional-pcb-upper.jpg|Voltage converter</gallery> == Reviews ==  <gallery>image:Amstrad_Computer_User8509025.jpg|Review in [Category[Amstrad Computer User]]image:HardwareAmstrad_Computer_User8509026.jpg|image:Amstrad_Computer_User8509027.jpg|image:Amstrad_Computer_User8509028.jpg|</gallery> == Manuals == * [[Media:RS232C Serial Interface (Amsoft UK) Manual.pdf|RS232C Serial Interface (Amsoft UK) Manual]] {{EN}} {{PDF}}* [[Media:RS232C Interface Serie (Amsoft FR) Manual.pdf|RS232C Interface Serie (Amsoft FR) Manual]] {{FR}} {{PDF}}* [[Original Amstrad RS232 interface|Manual of the original RS232 by Amstrad (OCR)]]* [[Media:RS232 (Pace) Manual.pdf|RS232 (Pace) Manual]] {{EN}} {{PDF}} == Downloads == * [[Media:RS232101.ZIP|ROM Image for original version]] - 8K ROM* [[Media:RS232Mercitel14.rom|ROM Image for Mercitel version]] - 16K ROM* [[Media:AmstradPaceSerialInterfaceCommstarRomImage.zip|ROM Image for Pace version]] - Commstar 32K ROM (two 16K banks)* [[Media:PACE232.ZIP|ROM Image for Pace version]] - Commstar 32K ROM  [[Category:Peripherals]] [[Category:Serial interfacesNetwork]][[Category:Communication Software]] [[Category:Serial_interfaces]][[Category:Amstrad Products]][[Category:Expansion ROM]]
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