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--- doc:cbm:io:iec:how_serial_bus_works [2022/08/16 12:32] – [STEP 3: SENDING THE BITS] eek
+++ doc:cbm:io:iec:how_serial_bus_works [2023/11/12 23:43] (current) – eek
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-//This article appeared in [[https://archive.org/stream/1983-07-compute-magazine/Compute_Issue_038_1983_Jul#page/n179/mode/2up|Compute! issue 38, July 1983]] and is Copyrighted 1983 by Jim Butterfield//
+//This article appeared in [[https://archive.org/stream/1983-07-compute-magazine/Compute_Issue_038_1983_Jul#page/n179/mode/2up|Compute! issue 38, July 1983]] and is Copyrighted 1983 by Jim Butterfield. This wiki rendition was done by Eek/Retrograde.//
 ====== HOW THE VIC/64 SERIAL BUS WORKS ======
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 ===== GROUND RULES =====
 To understand the workings of this bus, you must work through a few concepts. Later, we'll get
-technical for this who want it.
+technical for those who want it.
 The bus, like the IEEE, has two modes of operation: Select mode, in which the computer calls all devices and asks for a specific device to remain connected after the call ("Jones, would you stay in my office after the meeting?"); and Data mode, in which actual
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 Normally, the computer is the only device that will pull ATN true. When it does so, all other devices drop what they are doing and become listeners.
-Signals sent by the computer during an ATN period look like ordinary characters - eight bits with the usual handshake - but they are not data. They are "Talk," "Listen," "Untalk," and "Unlisten" commands telling a specific device that it will become (or cease to be) a talker or listener. The commands go to all devices, and all devices acknowledge them, but only the ones with the suitable device numbers will switch into talk and listen mode. These commands are sometimes followed by a secondary address, and after ATN is released, perhaps by a file name.
+Signals sent by the computer during an ATN period look like ordinary characters - eight bits with the usual handshake - but they are not data. They are "Talk," "Listen," "Untalk," and "Unlisten" commands telling a specific device that it will become (or cease to be) a talker or listener. The commands go to all devices, and all devices acknowledge them, //but only the ones with the suitable device numbers will switch into talk and listen mode//. These commands are sometimes followed by a secondary address, and after ATN is released, perhaps by a file name.
 An example might help give an idea of the nature of the communications that take place. To open for writing a sequential disk file called "XX," the following sequence would be sent with ATN on:DEVICE-8-LISTEN;SECONDARY-ADDRESS-2-OPEN. When ATN switches off, the computer will be waiting as a talker, holding the Clock line true; and the disk will be the listener, holding the Data line true. That's good, because the computer has more to send, and it will transmit: X;X;comma;s;comma;W - the W will be accompanied with an EOI