Changes

[[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).

Note: == 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]]). ActuallyThe DIY port address, a RS232 interface is very much timings and handshake signals are exactly the same as a BTX interface (in the actual BTX modem must be rented separately from Deutsche Bundespost), so even the PCB may be original Schneider version - except that DCD (almost/exactly?Data Carrier Detect) isn't implemented in the same for both devicesDIY version.

F8E0h - [[Z80-STI]] Indirect Data Register F8E1h - [[Z80-STI]] General Purpose I/O Data Register (0=Low, 1=High) F8E2h - [[Z80-STI]] Interrupt Pending Register B (write 0=clear, 1=unchanged) ;\ F8E3h - [[Z80-STI]] Interrupt Pending Register A (write 0=clear, 1=unchanged) ; F8E4h - [[Z80-STI]] Interrupt in-Service Register B ; not used F8E5h - [[Z80-STI]] Interrupt in-Service Register A ; F8E6h - [[Z80-STI]] Interrupt Mask Register B (0=masked, 1=unmasked) ; F8E7h - [[Z80-STI]] Interrupt Mask Register A (0=masked, 1=unmasked) ;/ F8E8h - [[Z80-STI]] Indirect Index and Interrupt Vector Register 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 F8EDh - [[Z80-STI]] Receiver Status Register F8EEh - [[Z80-STI]] Transmitter Status Register F8EFh - [[Z80-STI]] USART Data Register

Aside from the above 16 directly addressable registers, there are 8 indirectly addressable ones. For details on the direct & indirect registers, see [[Z80-STI]].

== Similar * Supported by "Starwriter".* BASIC example (or identical?for the official version) Interface ==is found in the Schneider RS232 manual (see below scans)* ASM example (for the DIY version) is included with [[Tim Riemann's RS232 interface]]

The circuit is very similar (or possibly indentical) to the [[Tim Riemann's RS232 interface]], both circuits are using a Z80 STI, both mapped to the same I/O port addresses. Whether or not the circuits are fully compatible with each other is '''unknown'''. Some small details might differ. For example, the clock source being passed to the Z80 STI chip could be different. == Manual (germanGerman) ==

* The MK68901 seems to be a newer/similar chip (but neither port addresses nor pinouts are backwards compatible). [[Category:Hardware]] [[Category:Peripherals]] [[Category:Serial_interfaces]]