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/* Datasheets */
µPD765 - Floppy Disc Controller (used in CPC 664, CPC 6128, 6128 Plus and [[DDI-1]] expansion).
Besides the Amstrad CPC, this chip equipped the [[PCW|Amstrad PCW]], the [[ZX Spectrum|ZX Spectrum +3]] , the [[SC-3000|Sega SC-3000]], and the [[PC|IBM PC]] (including [[Amstrad PC]]).
The recommended ports used by Amstrad and compatible interfaces are:
* Result Phase: Returns up to 7 result bytes (depending on the command) that are containing status information. During the result phase, all the result bytes must be read. The FDC will not accept a new command until all the result bytes are read.
Note: The Recalibrate and Seek Track commands do not return result bytes directly. Instead, instead the program must wait until the Main Status Register signalizes that the command has been completed, and . And then it must (!) send a Sense Interrupt State command to 'terminate' the Seek/Recalibrate command.
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== Chip Variants == === IC Models used in CPC ===
More than one manufacturer made 765 compatible ICs. These are the ones known to be used in the CPC by looking at pictures of CPC mainboards. All should operate almost identically.
All the floppy disk drive models used by Amstrad are referenced here: [https://www.cpcwiki.eu/index.php/Amstrad_FDD_part Amstrad FDD part]
Intel has also produced successors of the 8272, such as the 82072, 82077 and 82078.
The КР1810ВГ72А is a Soviet clone of the Intel i8272. It is used in the [[Aleste 520EX]] clone of the Amstrad CPC computer.
The [https://map.grauw.nl/resources/disk/toshiba_tc8566af.pdf Toshiba TC8566AF] is also a variant of the FDC765.
=== Competitors ===
The main competitor of the µPD765 FDC chip on the market was the WD179x FDC chip family. Its main differences are:
* the 765 only does standard track formats (preamble, marks and data fields), while the 179x will write anything you tell it in the write track (formatting a track) mode.
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* [[Media:UPD765_App_Note_Mar79.pdf| NEC uPD765 Datasheet preliminary (1979)]] [[Media:D765 NEC.pdf]] [[Media:UPD765-NEC.pdf]] [[Media:Z765A datasheet.pdf]] - uPD765 disc controller
* [[Media:Intel 8272A Datasheet preliminary (1982).pdf]] [[Media:Datasheet.hk_d8272a_2873060.pdf|Intel 8272A Datasheet (1986)]] [[Media:Floppy Disk Controller(FDC) UM8272A UM8272A-4.pdf]] - Licensed clone of the uPD765
* [[Media:TN6-1 9216 Floppy Disk Data Separator Jun82.pdf]] [[Media:FDC9216 datasheet.PDF]] [[Media:SED9420.pdf]] - Data separators
* [[Media:DDI Schematic.png]] - DDI-1 Schematic (disc interface for CPC464)
*[http://quasar.cpcscene.net/doku.php?id=assem:fdc Quasar FDC documentation (in french)]
*[https://64nops.wordpress.com/2021/07/04/a-la-decouverte-du-fdc/ FDC blog articles (in french)]
*[https://en.wikipedia.org/wiki/History_of_the_floppy_disk History of the floppy disk] Wikipedia article
*[https://www.cpc-power.com/cpcarchives/index.php?page=articles&num=92 Floppy disk formats (in french)]
*[https://www.fvempel.nl/3bible.html The 3inch bible]
*[https://info-coach.fr/atari/hardware/FD-Hard.php Atari ST Floppy Drive hardware analysis]
*[https://map.grauw.nl/articles/low-level-disk/ MSX low-level disk storage article]
*[https://youtu.be/aoXr7Anr5DY Réparation de lecteurs Amstrad CPC] by [[Rodrik Studio]]*[https://youtu.be/-A-USMg9xvE Un Gotek dans un CPC 6128 et du 5.25 aussi] by [[Rodrik Studio]]*[https://youtu.be/QPFVfgaMv68 Les disquettes : Le fonctionnement] by [[Rodrik Studio]]*[https://youtu.be/RMTYevdGH6I Les protections et bien plus] by [[Rodrik Studio]]*[https://github.com/dbalsom/fluxfox FluxFox] A floppy disk image library in Rust
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[[Category:CPC Internal Components]][[Category:Programming]][[Category:DATA Storage]][[Category:Electronic Component]]
