PSG Registers R11 - R13 - Revision history

Mr z: Protected "PSG Registers R11 - R13" ([edit=autoconfirmed] (indefinite) [move=autoconfirmed] (indefinite))

2010-12-04T09:03:45Z

Protected "PSG Registers R11 - R13" ([edit=autoconfirmed] (indefinite) [move=autoconfirmed] (indefinite))

Mr z at 00:40, 21 January 2005

2005-01-21T00:40:38Z

Mr z at 00:31, 21 January 2005

2005-01-21T00:31:48Z

Mr z at 00:31, 21 January 2005

2005-01-21T00:31:01Z

Mr z at 00:30, 21 January 2005

2005-01-21T00:30:20Z

Mr z at 00:29, 21 January 2005

2005-01-21T00:29:14Z

New page

Volume levels and envelope selects for channels A, B and C. Channel A uses R11, channel B uses R12 and channel C uses R13. See [[PSG#Channels|PSG Channels]] and [[PSG#Envelope Generator|PSG Envelope Generator]] for more details.

0000:0000:00ee:vvvv
where:
ee selects the envelope magnitude
00 No envelope selected. PSG uses the flat volume in 'vvvv' instead.
01 Use envelope volume, shifted right by 2
10 Use envelope volume, shifted right by 1
11 Use envelope volume as-is
vvvv indicates the flat volume to use if no envelope selected (ee is 00).

Some variants of the AY-3-891x family do not implement both envelope select bits. Those devices only allow selecting the unmodified envelope or a flat volume. On those devices, bit 5 always reads as 0. To ensure compatibility across both variants of the PSG, programs should always writes 1s to both 'e' bits, and also should not rely on a 1 written to bit 5 reading back as 1 or 0. (Writing 0 to bit 5 and subsequently reading it always gives 0 in bit 5.)

← Older revision		Revision as of 00:31, 21 January 2005
Line 10:		Line 10:
	vvvv indicates the flat volume to use if no envelope selected (ee is 00).		vvvv indicates the flat volume to use if no envelope selected (ee is 00).

−	Some variants of the AY-3-891x family do not implement both envelope select bits. Those devices only allow selecting the unmodified envelope or a flat volume. On those devices, bit 5 always reads as zero (0). To ensure compatibility across both variants of the PSG, programs should always ~~writes~~ ones (1) to both 'e' bits, and also should not rely on a one (1) written to bit 5 reading back as one (1) or zero (0). (Writing zero (0) to bit 5 and subsequently reading it always gives zero (0).)	+	Some variants of the AY-3-891x family do not implement both envelope select bits. Those devices only allow selecting the unmodified envelope or a flat volume. On those devices, bit 5 always reads as zero (0). To ensure compatibility across both variants of the PSG, programs should always write ones (1) to both 'e' bits, and also should not rely on a one (1) written to bit 5 reading back as one (1) or zero (0). (Writing zero (0) to bit 5 and subsequently reading it always gives zero (0).)

← Older revision		Revision as of 00:31, 21 January 2005
Line 10:		Line 10:
	vvvv indicates the flat volume to use if no envelope selected (ee is 00).		vvvv indicates the flat volume to use if no envelope selected (ee is 00).

−	Some variants of the AY-3-891x family do not implement both envelope select bits. Those devices only allow selecting the unmodified envelope or a flat volume. On those devices, bit 5 always reads as 0. To ensure compatibility across both variants of the PSG, programs should always writes ones (1) to both 'e' bits, and also should not rely on a one (1) written to bit 5 reading back as one (1) or zero (0). (Writing zero (0) to bit 5 and subsequently reading it always gives zero (0).)	+	Some variants of the AY-3-891x family do not implement both envelope select bits. Those devices only allow selecting the unmodified envelope or a flat volume. On those devices, bit 5 always reads as zero (0). To ensure compatibility across both variants of the PSG, programs should always writes ones (1) to both 'e' bits, and also should not rely on a one (1) written to bit 5 reading back as one (1) or zero (0). (Writing zero (0) to bit 5 and subsequently reading it always gives zero (0).)

← Older revision		Revision as of 00:30, 21 January 2005
Line 10:		Line 10:
	vvvv indicates the flat volume to use if no envelope selected (ee is 00).		vvvv indicates the flat volume to use if no envelope selected (ee is 00).

−	Some variants of the AY-3-891x family do not implement both envelope select bits. Those devices only allow selecting the unmodified envelope or a flat volume. On those devices, bit 5 always reads as 0. To ensure compatibility across both variants of the PSG, programs should always writes 1s to both 'e' bits, and also should not rely on a 1 written to bit 5 reading back as 1 or 0. (Writing 0 to bit 5 and subsequently reading it always gives 0 ~~in bit 5~~.)	+	Some variants of the AY-3-891x family do not implement both envelope select bits. Those devices only allow selecting the unmodified envelope or a flat volume. On those devices, bit 5 always reads as 0. To ensure compatibility across both variants of the PSG, programs should always writes ones (1) to both 'e' bits, and also should not rely on a one (1) written to bit 5 reading back as one (1) or zero (0). (Writing zero (0) to bit 5 and subsequently reading it always gives zero (0).)

← Older revision	Revision as of 09:03, 4 December 2010
(No difference)

@@ Line 5: / Line 5: @@
          ee          selects the envelope magnitude
   No envelope selected.  PSG uses the flat volume in 'vvvv' instead.
-  Use envelope volume, shifted right by 2
+  Use envelope volume shifted right by 2
-  Use envelope volume, shifted right by 1
+  Use envelope volume shifted right by 1
   Use envelope volume as-is
          vvvv        indicates the flat volume to use if no envelope selected (ee is 00).
 Some variants of the AY-3-891x family do not implement both envelope select bits.  Those devices only allow selecting the unmodified envelope or a flat volume.  On those devices, bit 5 always reads as zero (0).  To ensure compatibility across both variants of the PSG, programs should always write ones (1) to both 'e' bits, and also should not rely on a one (1) written to bit 5 reading back as one (1) or zero (0).  (Writing zero (0) to bit 5 and subsequently reading it always gives zero (0).)