Four floppy drives with Amstrad disc interface - Revision history

Ygdrazil at 08:56, 1 September 2014

2014-09-01T08:56:51Z

← Older revision		Revision as of 08:56, 1 September 2014
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	2 drives (A1 and A2) are in the collection for drive A. A switch chooses which A1 or A2 is drive A.		2 drives (A1 and A2) are in the collection for drive A. A switch chooses which A1 or A2 is drive A.
	2 drives (B1 and B2) are in the collection for drive B. A switch chooses which B1 or B2 is drive B.		2 drives (B1 and B2) are in the collection for drive B. A switch chooses which B1 or B2 is drive B.

			[[Category:Peripherals]][[Category:DIY]][[Category:DATA Storage]]

Arnoldemu: /* Four drives hardware modification */

2010-12-22T17:30:50Z

Four drives hardware modification

← Older revision		Revision as of 17:30, 22 December 2010
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	The NEC765 floppy disc controller used by Amstrad can support up to 4 drives. However, in the Amstrad disc interface, only the US0 output is connected. This then decodes into two drive selects (/DRIVE SELECT 0 and /DRIVE SELECT 1).		The NEC765 floppy disc controller used by Amstrad can support up to 4 drives. However, in the Amstrad disc interface, only the US0 output is connected. This then decodes into two drive selects (/DRIVE SELECT 0 and /DRIVE SELECT 1).

			The CPC6128 uses a 74LS38 (Quad 2-input NAND) to generate the select for drive 1, the select for drive 0 is generated from this using VCC, resistor and KTC1815.

	With a hardware modification, internal in the CPC664, CPC6128 or 6128+, or internal to the DDI-1, the US1 output can also be connected, and now four drives can be accessed using the NEC765 directly.		With a hardware modification, internal in the CPC664, CPC6128 or 6128+, or internal to the DDI-1, the US1 output can also be connected, and now four drives can be accessed using the NEC765 directly.

	~~Note that most Amstrad software, including AMSDOS, supports only~~ 2 ~~drives~~.		To do this a 2-to-4 decoder should be used instead. (i.e. 74LS139)

	~~FutureOS however~~, ~~can support~~ 4 drives ~~with a hardware modification like this~~.		Note that most Amstrad software, including AMSDOS supports only 2 drives. So to use the 4 drives you need to access the NEC765 directly.

			FutureOS supports this hardware modification and can use the 4 floppy drives.
			(As a side note, FutureOS supports 8 floppy drives, but the other 4 are provided by adding a Vortex Disc Interface in addition to an Amstrad Disc interface).

	==Alternatives==		==Alternatives==

Arnoldemu: Created page with "==Four floppy drives with Amstrad disc interface== The Amstrad disc interface (DDI-1 or the disc hardware within CPC664, CPC6128 and 6128+) supports a maximum of 2 drives, altho..."

2010-12-22T12:51:43Z

Created page with "==Four floppy drives with Amstrad disc interface== The Amstrad disc interface (DDI-1 or the disc hardware within CPC664, CPC6128 and 6128+) supports a maximum of 2 drives, altho..."

New page

==Four floppy drives with Amstrad disc interface==

The Amstrad disc interface (DDI-1 or the disc hardware within CPC664, CPC6128 and 6128+) supports a maximum of 2 drives, although the NEC765 used within the interface supports up to 4 drives.

NOTE: The Vortex disc interface, the version which contains the NEC765 can access up to 4 drives directly.

==Four drives hardware modification==

The NEC765 floppy disc controller used by Amstrad can support up to 4 drives. However, in the Amstrad disc interface, only the US0 output is connected. This then decodes into two drive selects (/DRIVE SELECT 0 and /DRIVE SELECT 1).

With a hardware modification, internal in the CPC664, CPC6128 or 6128+, or internal to the DDI-1, the US1 output can also be connected, and now four drives can be accessed using the NEC765 directly.

Note that most Amstrad software, including AMSDOS, supports only 2 drives.

FutureOS however, can support 4 drives with a hardware modification like this.

==Alternatives==

It is possible to use 4 drives without any internal modifications. The NEC765 will still see 2 drives and this method is compatible with all existing software.
Using switches you can choose 1 drive out of a collection of drives to act as A, and with a second switch choose 1 drive out of another collection to act as B.

e.g.
2 drives (A1 and A2) are in the collection for drive A. A switch chooses which A1 or A2 is drive A.
2 drives (B1 and B2) are in the collection for drive B. A switch chooses which B1 or B2 is drive B.