SYMBiFACE II:Rewriteable roms - Revision history

Arnoldemu at 15:38, 6 February 2016

2016-02-06T15:38:04Z

← Older revision		Revision as of 15:38, 6 February 2016
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	When J2 is connected and all switches are off then no roms are visible. This now allows you to program the ROMs safely.		When J2 is connected and all switches are off then no roms are visible. This now allows you to program the ROMs safely.

	~~NOTE~~: Symbiface 2 does a partial decode of the current rom written to #df00. It only processes the lower 5 bits. This means the roms will repeat 4 times through the entire 256 ROM range. This also means they will override Plus cartridge pages.		Selecting the ROM is done by writing the number to i/o port dfxx. Symbiface decodes the upper 8-bit of the address completely. It looks for the following pattern:

			11011111xxxxxxxx -> dfxx

			Other expansions do a partial decode of the i/o address only testing bit 13 of the address.

			Symbiface 2 also does a partial decode of the current rom number written to #df00. It only processes the lower 5 bits. This means the roms will repeat 4 times through the entire 256 ROM range. This also means they will override Plus cartridge pages.

	Symbiface 2 also has the potential to override rom 7 (AMSDOS). On some CPCs this is 100% reliable, on others it is not possible and on some it is unreliable.		Symbiface 2 also has the potential to override rom 7 (AMSDOS). On some CPCs this is 100% reliable, on others it is not possible and on some it is unreliable.



	== Mechanisms ==		== Mechanisms ==

Arnoldemu at 10:39, 31 January 2016

2016-01-31T10:39:23Z

← Older revision		Revision as of 10:39, 31 January 2016
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	NOTE: Symbiface 2 does a partial decode of the current rom written to #df00. It only processes the lower 5 bits. This means the roms will repeat 4 times through the entire 256 ROM range. This also means they will override Plus cartridge pages.		NOTE: Symbiface 2 does a partial decode of the current rom written to #df00. It only processes the lower 5 bits. This means the roms will repeat 4 times through the entire 256 ROM range. This also means they will override Plus cartridge pages.

			Symbiface 2 also has the potential to override rom 7 (AMSDOS). On some CPCs this is 100% reliable, on others it is not possible and on some it is unreliable.

	== Mechanisms ==		== Mechanisms ==

Arnoldemu at 10:38, 31 January 2016

2016-01-31T10:38:02Z

← Older revision		Revision as of 10:38, 31 January 2016
Line 9:		Line 9:
	When J2 is connected and all switches are off then no roms are visible. This now allows you to program the ROMs safely.		When J2 is connected and all switches are off then no roms are visible. This now allows you to program the ROMs safely.

	NOTE: Symbiface 2 does a partial decode of the current rom written to #df00. It only processes the lower 5 bits. This means the roms will repeat 4 times through the entire 256 ROM range. This also means they will ~~clash with C4CPC and~~ Plus cartridge ~~roms~~.		NOTE: Symbiface 2 does a partial decode of the current rom written to #df00. It only processes the lower 5 bits. This means the roms will repeat 4 times through the entire 256 ROM range. This also means they will override Plus cartridge pages.

	== Mechanisms ==		== Mechanisms ==

Arnoldemu at 10:36, 31 January 2016

2016-01-31T10:36:11Z

← Older revision		Revision as of 10:36, 31 January 2016
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	When J2 is connected and all switches are off then no roms are visible. This now allows you to program the ROMs safely.		When J2 is connected and all switches are off then no roms are visible. This now allows you to program the ROMs safely.

			NOTE: Symbiface 2 does a partial decode of the current rom written to #df00. It only processes the lower 5 bits. This means the roms will repeat 4 times through the entire 256 ROM range. This also means they will clash with C4CPC and Plus cartridge roms.

	== Mechanisms ==		== Mechanisms ==

Arnoldemu at 10:34, 31 January 2016

2016-01-31T10:34:46Z

← Older revision		Revision as of 10:34, 31 January 2016
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	The re-writeable ROMs are stored on a static RAM. The static RAM is powered by a CR2032 battery to remember it's contents when the symbiface 2 is powered down.		The re-writeable ROMs are stored on a static RAM. The static RAM is powered by a CR2032 battery to remember it's contents when the symbiface 2 is powered down.

			J2 on the Symbiface 2 controls visibility of roms 8-31 to the CPC. J2 when connected stops them being visible, when disconnected roms 8-31 are visible.

			There are 8 switches which control visibility of roms 0-7 to the CPC.

			When J2 is connected and all switches are off then no roms are visible. This now allows you to program the ROMs safely.

	== Mechanisms ==		== Mechanisms ==
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	{\|{{Prettytable\|width: 700px; font-size: 2em;}}		{\|{{Prettytable\|width: 700px; font-size: 2em;}}
	\|'''INP &FD17''' \|\| show the current ROM (selected by #df00) between #4000 and #7fff. Now it can be read and ~~rewritten~~. You do not need to enable the upper rom using port #7fxx ~~and all roms can be read/written regardless of J2 state or rom enable/disable state~~.		\|'''INP &FD17''' \|\| show the current ROM (selected by #df00) between #4000 and #7fff. Now it can be read and written. All roms on the Symbiface 2 can be accessed this way regardless of J2 or dipswitches state. You also do not need to enable the upper rom using port #7fxx.
	\|-		\|-
	\|'''OUT &FD17''' \|\| disable the ~~previouse~~ mentioned ROM write mode.		\|'''OUT &FD17''' \|\| disable the previously mentioned ROM write mode. Any value can be written.
	\|-		\|-
	\|'''OUT &FD11''' \|\| disable all SYMBiFACE II Roms. ~~You won't see any additional ROMS anymore~~, only ~~the CPCs~~' inbuilt ones.		\|'''OUT &FD11''' \|\| disable all SYMBiFACE II Roms. The roms will not be visible to the CPC, you will only see CPC's inbuilt ones or ROMs from other rom-boards.
	\|-		\|-
	\|'''INP &FD11''' \|\| enable the SYMBiFACE II roms.		\|'''INP &FD11''' \|\| enable the SYMBiFACE II roms. Symbiface 2 roms will be visible if enabled through J2 or switches.
	\|}		\|}

Arnoldemu: /* Mechanisms */

2016-01-31T10:07:13Z

Mechanisms

← Older revision		Revision as of 10:07, 31 January 2016
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	{\|{{Prettytable\|width: 700px; font-size: 2em;}}		{\|{{Prettytable\|width: 700px; font-size: 2em;}}
	\|'''INP &FD17''' \|\| show the current ROM (selected by #df00) between #4000 and #7fff. Now it can be read and rewritten.		\|'''INP &FD17''' \|\| show the current ROM (selected by #df00) between #4000 and #7fff. Now it can be read and rewritten. You do not need to enable the upper rom using port #7fxx and all roms can be read/written regardless of J2 state or rom enable/disable state.
	\|-		\|-
	\|'''OUT &FD17''' \|\| disable the previouse mentioned ROM write mode.		\|'''OUT &FD17''' \|\| disable the previouse mentioned ROM write mode.

Arnoldemu at 10:04, 31 January 2016

2016-01-31T10:04:54Z

← Older revision		Revision as of 10:04, 31 January 2016
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	This article decribes, how to map the '''rewriteable ROMs''' of the [[SYMBiFACE II]] card into the ram area, so that you can change its content.		This article decribes, how to map the '''rewriteable ROMs''' of the [[SYMBiFACE II]] card into the ram area so that you can change its content.

			The re-writeable ROMs are stored on a static RAM. The static RAM is powered by a CR2032 battery to remember it's contents when the symbiface 2 is powered down.

	== Mechanisms ==		== Mechanisms ==

Prodatron: /* Mechanisms */

2007-01-21T08:17:56Z

Mechanisms

← Older revision		Revision as of 08:17, 21 January 2007
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	== Mechanisms ==		== Mechanisms ==

	Please note, that the following commands ignore all values. So it doesn't matter, what you "out". When you "inp" you won't get any ~~senseless~~ numbers.		Please note, that the following commands ignore all values. So it doesn't matter, what you "out". When you "inp" you won't get any meaningful numbers.

	{\|{{Prettytable\|width: 700px; font-size: 2em;}}		{\|{{Prettytable\|width: 700px; font-size: 2em;}}

83.26.251.89: /* Mechanisms */

2007-01-14T14:21:09Z

Mechanisms

← Older revision		Revision as of 14:21, 14 January 2007
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	{\|{{Prettytable\|width: 700px; font-size: 2em;}}		{\|{{Prettytable\|width: 700px; font-size: 2em;}}
	\|'''INP &FD17''' \|\| show the current ROM (selected by #df00) between #4000 and #7fff. No it can be read and rewritten.		\|'''INP &FD17''' \|\| show the current ROM (selected by #df00) between #4000 and #7fff. Now it can be read and rewritten.
	\|-		\|-
	\|'''OUT &FD17''' \|\| disable the previouse mentioned ROM write mode.		\|'''OUT &FD17''' \|\| disable the previouse mentioned ROM write mode.

Prodatron: added category

2006-08-28T00:10:27Z

added category

← Older revision		Revision as of 00:10, 28 August 2006
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	* [[Programming:SYMBiFACE_II\|SYMBiFACE II documentations]]		* [[Programming:SYMBiFACE_II\|SYMBiFACE II documentations]]

			[[Category:Programming]]