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[[RS232 ]] Interface for the CPC by [[Schneider]]. Schneider is the german German distributor for Amstrad CPC hardware (however, thisinterface seems to be was Schneider's own invention, not an [[Amstrad ]] product).

== Clones == The uncommon shape of the housing dates back to a original [[Schneider BTX modul (which RS232 Interface]] was being intended to be plugged into released around 1985. Two years later, in 1987, a software-compatible clone was released as DIY schematic in a German book ([[Maschinenspracheprogramme und Hardware-Erweiterungen für Schneider Television SetsCPC's|link]]). Apparently Schneider produced too many housingsEven later, and re-used them for around 1996, a copy of that DIY schematic also circulated in the internet ([[Tim Riemann's RS232 interface|link]]). The DIY port address, timings and handshake signals are exactly the same as in the original Schneider version - except that DCD (Data Carrier Detect) isn't implemented in the DIY version.

Default I/O addresses are F8E0h-F8EFh (though the interface can be jumpered to use different addresses).  F8E0h - [[Z80 -STI ]] Indirect Data Register Read Write F8E1h - [[Z80 -STI Gen. ]] General Purpose I/O Data Register F8E2h - [[Z80-STI]] Interrupt Pending Register B ;\ F8E3h - [[Z80-STI]] Interrupt Pending Register A ; F8E4h - [[Z80-STI]] Interrupt in-Service Register B Read Write; not used F8E5h - [[Z80-STI]] Interrupt in-Service Register A ; F8E6h - [[Z80-STI]] Interrupt Mask Register B ; F8E7h - [[Z80-STI]] Interrupt Mask Register A ;/ F8E8h - [[Z80 -STI Pointer ]] Indirect Index and Interrupt Vector Register Read Write F8E9h - [[Z80-STI]] Timers A and B Control Register ;\ F8EAh - [[Z80-STI]] Timer B Data Register ; not used F8EBh - [[Z80-STI]] Timer A Data Register ;/ F8ECh - [[Z80 -STI ]] USART Control Register Read Write F8EDh - [[Z80 -STI ]] Receiver Status Register Read Write F8EEh - [[Z80 -STI ]] Transmitter Status Register Read Write F8EFh - [[Z80 -STI ]] USART Data Register Read Write Aside from the above 16 directly addressable registers, there are 8 indirectly addressable ones. For details on the direct & indirect registers, see [[Z80-STI]].

* Supported by "Starwriter".* BASIC example (for the official version) is found in the Schneider RS232 manual (see below scans)* ASM example (for the DIY version) is included with [[Tim Riemann's RS232 interface]] == Similar Manual (or identical?German) Interface == <gallery>File:SchneiderSioManualPage1.jpg|Page 1 (cable / jumpers)File:SchneiderSioManualPage2.jpg|Page 2 (schematic)File:SchneiderSioManualPage3.jpg|Page 3 (z80-sti registers)File:SchneiderSioManualPage4.jpg|Page 4 (blank / footer)</gallery> == Note == The uncommon shape of the housing dates back to a Schneider BTX modul (which was being intended to be plugged into Schneider Television Sets). Apparently Schneider produced too many housings, and re-used them for the RS232 interface. Actually, a RS232 interface is very much the same as a BTX interface (the actual BTX modem must be rented separately from Deutsche Bundespost), so even the PCB may be (almost/exactly?) the same for both devices.

== Datasheet A review appeared in German magazine [[CPC Schneider International]] (Missingissue 12-1985, pages [[Media:Schneider International 8512-p038 - Schneider RS232.jpg|38]], [[Media:Schneider International 8512-p039 - Schneider RS232.jpg|39]]) ==.

* The MK68901 seems to be A [[Media:Mostek_3801_Data.pdf|"Z80 STI"]] is a newer/similar 40pin [[Media:Mostek_3801_Data.pdf|MK3801]] chip from Mostek. Details on that chip (but neither port addresses nor pinouts are backwards compatiblefrom the "MOSTEK 1982/1983 Microelectronic Data Book" (kindly made available by John Robertson).

[[Category:Hardware]] [[Category:Peripherals]] [[Category:Serial_interfaces]]