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This [[RS232Image:CPCAI-RS232interface.jpg|thumb|[[Octoate|Octoate's]] interface was published as a DIY project in a special edition self-built version of the the Germanmagazine: CPC Schneider International(Sonderheft, #3-1986)CPCI RS232 interface]]

This [[RS232]] interface was published as a DIY project in a special edition of the the German magazine: [[CPC Schneider International Sonderheft]] (#3-1986) and also in a later issue. As the standard CPC series does not include a [[RS232]], this interface was very handy in order to communicate with other computers(eg. IBM PCs). A major drawback was the missing interrupt line which means that your programs have to poll the interface. == Software == A terminal program, written by [[The Cranium]], for this serial interface was published in the last issue of the [[CPC Schneider International]] (12/1 1992/1993).

Based around: Contains a single 25pin DSUB connector, a MC6850chip (ACIA), MAX 232 voltage converter, 74LS138 and MAX232Ports used: F8DC - Control register74LS85 address decoders, F8DD and a 4MHz oscillator with HEF 4060 clock divider, the clock divider connects to a mechanic switch, allowing to select between 19.2kHz and 38.4kHz. Four dip- Data registerswitches allow to select the port addresses (FxDCh and FxDDh, with x=0..F, usually x=8).

F8DCh CPCI Serial Interface MC6850 Control/Status Register (R/W) F8DDh CPCI Serial Interface MC6850 Data Register (R/W) * [[6850 ACIA chip]] * [[Media:MC6850.pdf|Motorola MC6850 datasheet]]* [[Media:Max232.pdf|MAX232 datasheet]] == How to build a RS232 interface (German) ==