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author Lord-Nightmare <Lord-Nightmare@users.noreply.github.com>2017-08-31 16:29:06 -0400
committer Lord-Nightmare <Lord-Nightmare@users.noreply.github.com>2017-08-31 16:29:06 -0400
commitc2dc813c4acc136039ec42c314bb8923d054df6a (patch)
treecbfa30598110286b3e98612b6477a99788e0565f /src
parente72b503c195f33e48ea8d2d88045de07df3ba9a5 (diff)
update ay8910/ym2203 notes (nw)
Diffstat (limited to 'src')
-rw-r--r--src/devices/sound/ay8910.cpp10
1 files changed, 6 insertions, 4 deletions
diff --git a/src/devices/sound/ay8910.cpp b/src/devices/sound/ay8910.cpp
index f5456163398..10c29f88eed 100644
--- a/src/devices/sound/ay8910.cpp
+++ b/src/devices/sound/ay8910.cpp
@@ -494,10 +494,12 @@ Yamaha YM2203: 2 I/O ports
The first 16 registers are the same(?) as the YM2149.
YM2203: Unused bits in registers have unknown behavior.
I/O current source/sink behavior is unknown.
- YM2203 die is unknown; two die revisions, 'F' and 'H', have been observed
- from Yamaha chip/datecode silkscreen surface markings. It is unknown
- what behavioral differences exist between these two revisions.
- The 'F' revision only appears during the first year of production.
+ YM2203 die is unknown; three die revisions, 'D', 'F' and 'H', have been
+ observed from Yamaha chip/datecode silkscreen surface markings. It is
+ unknown what behavioral differences exist between these revisions.
+ The 'D' revision only appears during the first year of production, 1984, on chips marked 'YM2203B'
+ The 'F' revision exists from 1984?-1991, chips are marked 'YM2203C'
+ The 'H' revision exists from 1991 onward, chips are marked 'YM2203C'
Yamaha YM3439: limited info: CMOS version of YM2149?
Yamaha YMZ284: limited info: 0 I/O port, different clock divider
The chip selection logic is again simplified here: pin 1 is /WR, pin 2 is