Peripheral Soft Reset - Revision history

OffseT at 08:26, 10 September 2022

2022-09-10T08:26:40Z

OffseT: /* Known Hardware */

2022-09-06T15:43:05Z

‎Known Hardware

OffseT: /* Known Hardware */

2022-09-06T11:46:20Z

‎Known Hardware

Arnoldemu at 10:55, 11 March 2018

2018-03-11T10:55:43Z

SyX at 16:44, 12 July 2014

2014-07-12T16:44:55Z

Nocash at 12:55, 29 April 2010

2010-04-29T12:55:05Z

Nocash at 12:54, 29 April 2010

2010-04-29T12:54:37Z

Nocash at 12:42, 29 April 2010

2010-04-29T12:42:04Z

Nocash at 20:58, 20 April 2010

2010-04-20T20:58:05Z

Nocash at 20:56, 20 April 2010

2010-04-20T20:56:02Z

@@ Line 15: / Line 15: @@
 == Known Hardware ==
-The Soft Reset feature is useful (initialize hardware expansions), but no used a lot; the [[PlayCity]], [[Nova]] and [[CPCISA by Yarek|CPCISA]] are the only hardware expansion using intentionally this feature (though when reverse engineering things by only examining the software drivers one may easily miss its presence, since the OUT [F8FFh] is issued by the BIOS, not by the driver).
+The Soft Reset feature is useful (initialize hardware expansions), but no used a lot; the [[PlayCity]], [[Nova]] and [[CPCISA]] are the only hardware expansion using intentionally this feature (though when reverse engineering things by only examining the software drivers one may easily miss its presence, since the OUT [F8FFh] is issued by the BIOS, not by the driver).
 Moreover, there are probably various devices that do not directly use Port F8FFh, but that do react to the OUT because of incomplete port decoding. For example, the [[ACU Real Time Clock (DIY)]] decodes only A10,A4,A3 of its Port FBFFh, and so, it will also react to OUT [F8FFh],FFh.

@@ Line 15: / Line 15: @@
 == Known Hardware ==
-The Soft Reset feature is useful (initialize hardware expansions), but no used a lot, the [[PlayCity]] and [[Nova]] are the only hardware expansion using intentionally this feature (though when reverse engineering things by only examining the software drivers one may easily miss its presence, since the OUT [F8FFh] is issued by the BIOS, not by the driver).
+The Soft Reset feature is useful (initialize hardware expansions), but no used a lot; the [[PlayCity]], [[Nova]] and [[CPCISA by Yarek|CPCISA]] are the only hardware expansion using intentionally this feature (though when reverse engineering things by only examining the software drivers one may easily miss its presence, since the OUT [F8FFh] is issued by the BIOS, not by the driver).
-−
-Aside the [[PlayCity]], the other known hardware that is (maybe unintentionally) using Port F8FFh is [[CPCISA by Yarek]].
 Moreover, there are probably various devices that do not directly use Port F8FFh, but that do react to the OUT because of incomplete port decoding. For example, the [[ACU Real Time Clock (DIY)]] decodes only A10,A4,A3 of its Port FBFFh, and so, it will also react to OUT [F8FFh],FFh.

@@ Line 15: / Line 15: @@
 == Known Hardware ==
-The Soft Reset feature is useful (initialize hardware expansions), but no used a lot, the [[PlayCity]] is the only hardware expansion using intentionally this feature (though when reverse engineering things by only examining the software drivers one may easily miss its presence, since the OUT [F8FFh] is issued by the BIOS, not by the driver).
+The Soft Reset feature is useful (initialize hardware expansions), but no used a lot, the [[PlayCity]] and [[Nova]] are the only hardware expansion using intentionally this feature (though when reverse engineering things by only examining the software drivers one may easily miss its presence, since the OUT [F8FFh] is issued by the BIOS, not by the driver).
 Aside the [[PlayCity]], the other known hardware that is (maybe unintentionally) using Port F8FFh is [[CPCISA by Yarek]].

← Older revision		Revision as of 10:55, 11 March 2018
Line 25:		Line 25:
	* [[Media:S158ap12.pdf\|SOFT 158 Appendix 12 (XII) (The Hardware)]] - general info on Port F8FFh (page 3)		* [[Media:S158ap12.pdf\|SOFT 158 Appendix 12 (XII) (The Hardware)]] - general info on Port F8FFh (page 3)
	* [[Media:S968ap13.pdf\|SOFT 968 Appendix 13 (XIII) (Hints Tips and Workarounds)]] - info on Port F8FFh and interrupts (page 7)		* [[Media:S968ap13.pdf\|SOFT 968 Appendix 13 (XIII) (Hints Tips and Workarounds)]] - info on Port F8FFh and interrupts (page 7)
		+
		+	[[Category:Hardware]]

@@ Line 15: / Line 15: @@
 == Known Hardware ==
-The Soft Reset feature isn't too useful, and there's no hardware known to be (intentionally) using that feature (though when reverse engineering things by only examining the software drivers one may easily miss its presence, since the OUT [F8FFh] is issued by the BIOS, not by the driver).
+The Soft Reset feature is useful (initialize hardware expansions), but no used a lot, the [[PlayCity]] is the only hardware expansion using intentionally this feature (though when reverse engineering things by only examining the software drivers one may easily miss its presence, since the OUT [F8FFh] is issued by the BIOS, not by the driver).
-The only known hardware that is (maybe unintentionally) using Port F8FFh is [[CPCISA by Yarek]].
+Aside the [[PlayCity]], the other known hardware that is (maybe unintentionally) using Port F8FFh is [[CPCISA by Yarek]].
 Moreover, there are probably various devices that do not directly use Port F8FFh, but that do react to the OUT because of incomplete port decoding. For example, the [[ACU Real Time Clock (DIY)]] decodes only A10,A4,A3 of its Port FBFFh, and so, it will also react to OUT [F8FFh],FFh.

@@ Line 1: / Line 1: @@
 Port F8FFh is a documented, but rarely known I/O address, used by the standard BIOS functions MC_BOOT_PROGRAM and MC_START_PROGRAM (vector BD13h and BD16h). These functions are usually executed when starting a binary program with RUN"FILENAME.BIN", both functions do issue an "OUT [F8FFh],FFh". This feature is intended to allow Peripherals to re-initialize themselves when needed. From the official [[SOFT158]] specs:
-:All expansion peripherals should be reset when an output is performed to I/O channel #F8FF. In particular a peripheral that generates interrupts must not generate an interrupt until it is re-initialised after such an output has been performed.
+:"All expansion peripherals should be reset when an output is performed to I/O channel #F8FF. In particular a peripheral that generates interrupts must not generate an interrupt until it is re-initialised after such an output has been performed."
 Most or all peripherals (including Amstrad's own [[DDI-1]]) aren't following that suggestion, and usually there is no need to do so. There may be a few special cases there hardware could take use of it, such like interrupt generating devices, especially if they do access formerly allocated memory.

← Older revision		Revision as of 12:54, 29 April 2010
Line 1:		Line 1:
−	Port F8FFh is a documented, but rarely known I/O address, used by the standard BIOS functions MC_BOOT_PROGRAM and MC_START_PROGRAM (vector BD13h and BD16h). These functions are usually executed when starting a binary program with RUN"FILENAME.BIN", both functions do issue an "OUT [F8FFh],FFh". This feature is ~~apparently~~ intended to allow Peripherals to re-initialize themselves when needed.	+	Port F8FFh is a documented, but rarely known I/O address, used by the standard BIOS functions MC_BOOT_PROGRAM and MC_START_PROGRAM (vector BD13h and BD16h). These functions are usually executed when starting a binary program with RUN"FILENAME.BIN", both functions do issue an "OUT [F8FFh],FFh". This feature is intended to allow Peripherals to re-initialize themselves when needed. From the official [[SOFT158]] specs:
		+
		+	:All expansion peripherals should be reset when an output is performed to I/O channel #F8FF. In particular a peripheral that generates interrupts must not generate an interrupt until it is re-initialised after such an output has been performed.
		+
		+	Most or all peripherals (including Amstrad's own [[DDI-1]]) aren't following that suggestion, and usually there is no need to do so. There may be a few special cases there hardware could take use of it, such like interrupt generating devices, especially if they do access formerly allocated memory.

	== Avoid this ==		== Avoid this ==

← Older revision		Revision as of 12:42, 29 April 2010
Line 19:		Line 19:
	== Offical Specs ==		== Offical Specs ==

−	* [[Media:S968ap13.pdf\|SOFT 968 Appendix 13 (XIII) (Hints Tips and Workarounds)]] - ~~includes~~ info on Port F8FFh	+	* [[Media:S158ap12.pdf\|SOFT 158 Appendix 12 (XII) (The Hardware)]] - general info on Port F8FFh (page 3)
		+	* [[Media:S968ap13.pdf\|SOFT 968 Appendix 13 (XIII) (Hints Tips and Workarounds)]] - info on Port F8FFh and interrupts (page 7)

← Older revision		Revision as of 20:58, 20 April 2010
Line 1:		Line 1:
−	Port F8FFh is ~~an undocumented and~~ rarely known I/O address, used by the standard BIOS functions MC_BOOT_PROGRAM and MC_START_PROGRAM (vector BD13h and BD16h). These functions are usually executed when starting a binary program with RUN"FILENAME.BIN", both functions do issue an "OUT [F8FFh],FFh". This feature is apparently intended to allow Peripherals to re-initialize themselves when needed.	+	Port F8FFh is a documented, but rarely known I/O address, used by the standard BIOS functions MC_BOOT_PROGRAM and MC_START_PROGRAM (vector BD13h and BD16h). These functions are usually executed when starting a binary program with RUN"FILENAME.BIN", both functions do issue an "OUT [F8FFh],FFh". This feature is apparently intended to allow Peripherals to re-initialize themselves when needed.

	== Avoid this ==		== Avoid this ==

← Older revision		Revision as of 20:56, 20 April 2010
Line 16:		Line 16:

	Moreover, there are probably various devices that do not directly use Port F8FFh, but that do react to the OUT because of incomplete port decoding. For example, the [[ACU Real Time Clock (DIY)]] decodes only A10,A4,A3 of its Port FBFFh, and so, it will also react to OUT [F8FFh],FFh.		Moreover, there are probably various devices that do not directly use Port F8FFh, but that do react to the OUT because of incomplete port decoding. For example, the [[ACU Real Time Clock (DIY)]] decodes only A10,A4,A3 of its Port FBFFh, and so, it will also react to OUT [F8FFh],FFh.
		+
		+	== Offical Specs ==
		+
		+	* [[Media:S968ap13.pdf\|SOFT 968 Appendix 13 (XIII) (Hints Tips and Workarounds)]] - includes info on Port F8FFh