Arnold4 - Revision history

Arnoldemu at 10:40, 11 March 2018

2018-03-11T10:40:16Z

← Older revision		Revision as of 10:40, 11 March 2018
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	[[File:Enable6128modeOn464PreAsic.jpg]]		[[File:Enable6128modeOn464PreAsic.jpg]]

			[[Category:Hardware]]

Gerald: Undo revision 95016 by TFM (talk)

2016-10-29T10:05:07Z

Undo revision 95016 by TFM (talk)

← Older revision		Revision as of 10:05, 29 October 2016
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	==ROM7 and ROMDIS in 6128 mode==		==ROM7 and ROMDIS in 6128 mode==
	* ROMDIS does not prevent internal ROM7 to be selected, as on ~~some~~ 6128, unlike plus range.		* ROMDIS does not prevent internal ROM7 to be selected, as on regular 6128, unlike plus range.
	* ROMDIS act as an output when ROM7 is selected (TBC : only on ROM7/0 ?)		* ROMDIS act as an output when ROM7 is selected (TBC : only on ROM7/0 ?)
	* ROMDIS act as the DDI1 ROMDIS as it is active even during ram accesses.		* ROMDIS act as the DDI1 ROMDIS as it is active even during ram accesses.

TFM: /* ROM7 and ROMDIS in 6128 mode */

2016-01-28T15:45:25Z

ROM7 and ROMDIS in 6128 mode

← Older revision		Revision as of 15:45, 28 January 2016
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	==ROM7 and ROMDIS in 6128 mode==		==ROM7 and ROMDIS in 6128 mode==
	* ROMDIS does not prevent internal ROM7 to be selected, as on ~~regular~~ 6128, unlike plus range.		* ROMDIS does not prevent internal ROM7 to be selected, as on some 6128, unlike plus range.
	* ROMDIS act as an output when ROM7 is selected (TBC : only on ROM7/0 ?)		* ROMDIS act as an output when ROM7 is selected (TBC : only on ROM7/0 ?)
	* ROMDIS act as the DDI1 ROMDIS as it is active even during ram accesses.		* ROMDIS act as the DDI1 ROMDIS as it is active even during ram accesses.

Gerald at 10:09, 4 September 2014

2014-09-04T10:09:52Z

← Older revision		Revision as of 10:09, 4 September 2014
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	[[File:6128 PreAsic PCB.png]]		[[File:6128 PreAsic PCB.png]]
			<br /><br />
	= Enabling 6128 mode on 464 =		= Enabling 6128 mode on 464 =
	Enabling the 6128 mode has two main advantages :		Enabling the 6128 mode has two main advantages :
	* Being fully compatible with 6128 memory modes, mainly C3 mode when upper ROM is enabled.		* Being fully compatible with 6128 memory modes, mainly C3 mode when upper ROM is enabled.
	* On board memory can be increased to 128kb.		* On board memory can be increased to 128kb.
			<br />
	The compatibility modification, which is reversible, is achieved by soldering two wires:		The compatibility modification, which is reversible, is achieved by soldering two wires:
	* one connecting IC101 pin 97 (L6N4) to ground, which configure the asic to work as a 6128		* one connecting IC101 pin 97 (L6N4) to ground, which configure the asic to work as a 6128
	* one connecting expansion port pin 48 (EXT/) to ground, preventing the asic to map the missing AMSDOS ROM in place of BASIC one.		* one connecting expansion port pin 48 (EXT/) to ground, preventing the asic to map the missing AMSDOS ROM in place of BASIC one.
			<br />
			The modifications are visible on the picture below

	~~The modifications are visible on the picture below~~
	[[File:Enable6128modeOn464PreAsic.jpg]]		[[File:Enable6128modeOn464PreAsic.jpg]]

Gerald: Added 464 to 6128 compatibility modification

2014-09-04T10:06:53Z

Added 464 to 6128 compatibility modification

← Older revision		Revision as of 10:06, 4 September 2014
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	[[File:6128 PreAsic PCB.png]]		[[File:6128 PreAsic PCB.png]]

			= Enabling 6128 mode on 464 =
			Enabling the 6128 mode has two main advantages :
			* Being fully compatible with 6128 memory modes, mainly C3 mode when upper ROM is enabled.
			* On board memory can be increased to 128kb.

			The compatibility modification, which is reversible, is achieved by soldering two wires:
			* one connecting IC101 pin 97 (L6N4) to ground, which configure the asic to work as a 6128
			* one connecting expansion port pin 48 (EXT/) to ground, preventing the asic to map the missing AMSDOS ROM in place of BASIC one.

			The modifications are visible on the picture below
			[[File:Enable6128modeOn464PreAsic.jpg]]

Gerald at 10:05, 3 December 2013

2013-12-03T10:05:27Z

← Older revision		Revision as of 10:05, 3 December 2013
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	In 464 mode :		In 464 mode :
	* the /ROM2 signal is always high : ROM7 selection is not handled on board.		* the /ROM2 signal is always high : ROM7 selection is not handled on board.
	* the /CAS1 signal is always high : RAM extension is not handled on board.		* the /CAS1 signal is always high : RAM extension is not handled on board.

	In 6128 mode :		In 6128 mode :
	* the /ROM2 signal is handled on board.		* the /ROM2 signal is handled on board like AMSDOS ROM is handled on 6128/DDI1. When /EXT tied low, /ROM2 will be active when ROM7 is selected. When /EXT is floating (ie pulled up), /ROM2 will be active when ROM0 is selected.
	* the /CAS1 is handled on board, ~~with the expected result of getting~~ garbage instead of base RAM when using RAM selection other than C0		* 464 will get stuck after displaying the copyright message and before the "BASIC 1.0" message as nothing is connected to /ROM2.
	* CPC does get stuck after displaying the copyright message and ~~before the "BASIC 1.0" message~~.		* the /CAS1 is handled on board. On 464, expect garbage instead of base RAM when using RAM selection other than C0 and no RAM extension connected.

	==Extension RAM management==		==Extension RAM management==
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	In 6128 mode :		In 6128 mode :
	* ~~Garbage~~ all the way on extension RAM with no extension connected, as expected as no ram is there ;D		* On a 464, garbage all the way on extension RAM with no extension connected, as expected as no ram is there.
			* adding 41464 in the alternate footprint and connected to CAS1 instead of CAS0 may transform the 464 in 4128
	* With an extension, C3 is working as expected		* With an extension, C3 is working as expected
	* adding 41464 in the alternate footprint and connected to CAS1 instead of CAS0 may transform the 464 in 4128 ;)

	==ROM7 and ROMDIS in 6128 mode==		==ROM7 and ROMDIS in 6128 mode==
	* ~~Well, no luck.~~ ROMDIS does not prevent internal ROM7 to be selected		* ROMDIS does not prevent internal ROM7 to be selected, as on regular 6128, unlike plus range.
	* ROMDIS act as an output when ROM7 is selected (~~However I need to re-check that it is~~ only ~~happening~~ on ~~ROM 7~~)		* ROMDIS act as an output when ROM7 is selected (TBC : only on ROM7/0 ?)
	* ROMDIS act as the ~~DDI~~ ROMDIS as it is active even during ram ~~access 10943-0~~		* ROMDIS act as the DDI1 ROMDIS as it is active even during ram accesses.
			<br />
			The following picture shows the ROM detection routine : Selection of ROM7, followed by a read at 0xC000 where ROMDIS is active as well as /ROM2
	[[File:CPC464PREASIC 6128mode ROM7.png]]		[[File:CPC464PREASIC 6128mode ROM7.png]]

	==/EXP==		==/EXP==

	~~When the~~ DDI1 extension is ~~not~~ plugged, /EXP is pulled high~~, and~~ /ROM2 signal is ~~in fact~~ ROM0 and replace the BASIC. As no ROM is connected, it just crash !		On a 464, when no DDI1 extension is plugged, /EXP is pulled high. /ROM2 signal is active as ROM0 and replace the BASIC. As no ROM is connected, it just crash !<br />
			On a 6128, /EXP is permanently tied to GND.

	==Bonus==		==Bonus==
	* on the ~~following page~~, ~~Gate Array and ASIC Pin-Outs - CPCWiki, pin~~ 35 and 36 are undocumented.		* In the amendment service manual, pins 35 and 36 are undocumented. However, according to the PCB mask, these pins goes to the FDC through links : pin 35 to DATA, pin 36 to WINDOW
	* on the PCB ~~in the amendment service manual~~, these to pins goes to the FDC ~~thru~~ links : pin 35 to DATA, pin 36 to WINDOW ~~10945-1~~		* Amstrad was designing its own data separator and planned to use it on this version of the CPC. But As hinted in [[Arnold_V_specs]], it was not ready.

	[[File:6128 PreAsic PCB.png]]		[[File:6128 PreAsic PCB.png]]

	* Looks like amstrad was designing its own data separator and planned to use it on this version of the CPC. But As hinted in Arnold V specs - CPCWiki, it was not ready.

Arnoldemu at 09:09, 3 December 2013

2013-12-03T09:09:08Z

← Older revision		Revision as of 09:09, 3 December 2013
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	The final cost down models came just before the release of the Amstrad plus.		The final cost down models came just before the release of the Amstrad plus.
	The same chip was used within ~~the~~ CPC464 and CPC6128.		The same chip was used within late CPC464 and CPC6128. It performs the operations of the PAL used in the CPC6128, the Gate-Array used in older CPCs and the CRTC.

			=CRTC=

	In CRTC terms it operates almost the same as the CRTC within the Plus ASIC.		In CRTC terms it operates almost the same as the CRTC within the Plus ASIC.

Arnoldemu: /* Bonus */

2013-12-03T09:07:10Z

Bonus

← Older revision		Revision as of 09:07, 3 December 2013
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	* on the following page, Gate Array and ASIC Pin-Outs - CPCWiki, pin 35 and 36 are undocumented.		* on the following page, Gate Array and ASIC Pin-Outs - CPCWiki, pin 35 and 36 are undocumented.
	* on the PCB in the amendment service manual, these to pins goes to the FDC thru links : pin 35 to DATA, pin 36 to WINDOW 10945-1		* on the PCB in the amendment service manual, these to pins goes to the FDC thru links : pin 35 to DATA, pin 36 to WINDOW 10945-1

			[[File:6128 PreAsic PCB.png]]

	* Looks like amstrad was designing its own data separator and planned to use it on this version of the CPC. But As hinted in Arnold V specs - CPCWiki, it was not ready.		* Looks like amstrad was designing its own data separator and planned to use it on this version of the CPC. But As hinted in Arnold V specs - CPCWiki, it was not ready.

Arnoldemu at 09:06, 3 December 2013

2013-12-03T09:06:41Z

← Older revision		Revision as of 09:06, 3 December 2013
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	In CRTC terms it operates almost the same as the CRTC within the Plus ASIC.		In CRTC terms it operates almost the same as the CRTC within the Plus ASIC.

			=Costdown IC pinout information=

	The following information relating to the pins of the IC was tested and verified by Gerald:		The following information relating to the pins of the IC was tested and verified by Gerald:

Arnoldemu: /* ROM7 and ROMDIS in 6128 mode */

2013-12-03T09:06:24Z

ROM7 and ROMDIS in 6128 mode

← Older revision		Revision as of 09:06, 3 December 2013
Line 35:		Line 35:
	* ROMDIS act as the DDI ROMDIS as it is active even during ram access 10943-0		* ROMDIS act as the DDI ROMDIS as it is active even during ram access 10943-0

	[File:CPC464PREASIC 6128mode ROM7.png]		[[File:CPC464PREASIC 6128mode ROM7.png]]

	==/EXP==		==/EXP==