From 0646440c51fbe2db6bd7dd93c4fc859106a70666 Mon Sep 17 00:00:00 2001 From: Jonathan Gevaryahu Date: Tue, 6 Jul 2010 07:15:36 +0000 Subject: [PATCH] fix an error in the new documentation comment, no whatsnew --- src/emu/sound/tms5220.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/src/emu/sound/tms5220.c b/src/emu/sound/tms5220.c index 5a4898bd36b..89ff8e894ca 100644 --- a/src/emu/sound/tms5220.c +++ b/src/emu/sound/tms5220.c @@ -106,14 +106,17 @@ Patent notes (important timing info for interpolation): 6 = >>1 (/2) (NOTE: this value may actually be >>2 (/4), the patent has an error on it and is unclear) 7 = >>1 (/2) 0 = >>0 (/1, forcing current values to equal target values) - Every IP full count, a new frame is parsed, but ONLY on the 0->* transition. - NOTE: on TMS5220C ONLY, the rate setting is implied by the datasheet to - determines what IP is reloaded to upon overflow; depending on the rate - setting it will be 0, 2, 4 or 6; other chips always reload to 0. + Every IP full count, a new frame is parsed, but ONLY on the 0->* + transition. + NOTE: on TMS5220C ONLY, the datasheet IMPLIES the following: + Upon new frame parse (end of IP=0), the IP is forced to a value depending + on the TMS5220C-specific rate setting. For rate settings 0, 1, 2, 3, it + will be forced to 1, 3, 5 or 7 respectively. On non-TMS5220 chips, it + counts as expected (IP=1 follows IP=0) always. This means, the tms5220c with rates set to n counts IP as follows: (new frame parse is indicated with a #) Rate IP Count - 00 7 0#1 2 3 4 5 6 7 0#1 2 3 4 5 6 7 + 00 7 0#1 2 3 4 5 6 7 0#1 2 3 4 5 6 7 <- non-tms5220c chips always follow this pattern 01 7 0#3 4 5 6 7 0#3 4 5 6 7 0#3 4 5 10 7 0#5 6 7 0#5 6 7 0#5 6 7 0#5 6 7 11 7 0#7 0#7 0#7 0#7 0#7 0#7 0#7 0#7