RCA CDP18S711 Instruction Manual
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Contents
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11. COSMAC VIP OperationCOSMAC VIP is operated with the RUN switch andhex keyboard. The PWR light shows that power is on.The Q light is activated by various programs. A tone issounded whenever the Q light is on. The TAPE lightglows when cassette input data is present. When usingCOSMAC VIP, always start with the RUN switch in thedown (or reset) position. Flipping the RUN switch upinitiates execution of machine language programsbeginning at memory location 0000. If you havepreviously stored the CHIP-8 Ian_ guage interpreterprogram at locations 0000-01FF, execution of a programwritten in this language will begin at 0200. To manuallyterminate execution of any program, flip RUN down.Using the Operating SystemWith COSMAC VIP you can load programs intomemory from the hex keyboard or cassette recorder,record the contents of memory on cassettes, show thecontents of memory bytes in hex form on the display,and examine the contents of CDP1802 microprocessorregisters. These functions are performed with the aid of aspecial program called an operating system. Thisoperating system is contained in a ROM so that it's readyto use as soon as power is turned on. It is located atmemory locations 8000-81FF. A machine code listingand summary of this operating system is provided inAppendix B.To use the operating system hold key C down on thehex keyboard when you flip RUN up. You will hear atone. Release key C and you're ready to use theoperating system.After selecting the operating system you can do fourdifferent operations as shown in the following table:9KEY OPERATION0AFBMW (Memory Write)MR (Memory Read)TW (Tape Write) TR(Tape Read)For any of these operations you must first enter amemory address. Enter the 4 hex digits of any memoryaddress using the hex keyboard (most significant digitfirst). You will see the address at the lower left of thescreen and the byte contained in that address at the lowerright. Remember that addresses and bytes are alwaysentered and shown in hex form. Suppose you entered0200. You will see 0200 at the bottom left of the screenand the byte stored at 0200 at the lower right.Memory WriteIf you want to change this byte, press the 0 key. Nowpress two digits of the new byte (most significant digitfirst) and it will be stored at 0200 replacing the originalbyte. You will see this change on the screen. If you enteranother byte it will be shown and stored at the nexthigher address in sequence (0201 in this example). Youcan load any, sequence of bytes directly from the hexkeyboard in this manner. If you make a mistake, flipRUN down. With key C pressed, flip RUN back up.Enter the address at which you made the error. Press key0 and resume entering your program.Note the random bit pattern on the screen above thehex display. This pattern is the binary data |
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