From c2dc813c4acc136039ec42c314bb8923d054df6a Mon Sep 17 00:00:00 2001 From: Lord-Nightmare Date: Thu, 31 Aug 2017 16:29:06 -0400 Subject: update ay8910/ym2203 notes (nw) --- src/devices/sound/ay8910.cpp | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'src') 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 -- cgit v1.2.3-70-g09d2