From b43a647b92c9f373b8ff7c10ea01dd35c9a5a723 Mon Sep 17 00:00:00 2001 From: Brian Troha Date: Sun, 29 Jul 2012 20:03:32 +0000 Subject: [PATCH] msm5205.c: Preserve the documentation differences between MSM6585 & MSM5205 now that support has been added to the msm5205.c driver. --- src/emu/sound/msm5205.c | 46 +++++++++++++++++++++++++++++------------ 1 file changed, 33 insertions(+), 13 deletions(-) diff --git a/src/emu/sound/msm5205.c b/src/emu/sound/msm5205.c index 6857bb97dff..6ff6ffef440 100644 --- a/src/emu/sound/msm5205.c +++ b/src/emu/sound/msm5205.c @@ -11,25 +11,45 @@ * for the current sample rate * * 01/06/99 - * separate MSM5205 emulator form adpcm.c and some fix + * separate MSM5205 emulator form adpcm.c and some fix + * + * 07/29/12 + * added basic support for the MSM6585 */ #include "emu.h" #include "msm5205.h" /* - * - * MSM 5205 ADPCM chip: - * - * Data is streamed from a CPU by means of a clock generated on the chip. - * - * A reset signal is set high or low to determine whether playback (and interrupts) are occuring - * - * - * TODO: - * - convert to modern - * - lowpass filter for MSM6585 - * + + MSM 5205 ADPCM chip: + + Data is streamed from a CPU by means of a clock generated on the chip. + + A reset signal is set high or low to determine whether playback (and interrupts) are occuring. + + MSM6585: is an upgraded MSM5205 voice synth IC. + Improvements: + More precise internal DA converter + Built in low-pass filter + Expanded sampling frequency + + Differences between MSM6585 & MSM5205: + + MSM6586 MSM5205 + Master clock frequency 640kHz 384kHz + Sampling frequency 4k/8k/16k/32kHz 4k/6k/8kHz + ADPCM bit length 4-bit 3-bit/4-bit + DA converter 12-bit 10-bit + Low-pass filter -40dB/oct N/A + Overflow prevent circuit Included N/A + + Timer callback at VCLK low edge on MSM5205 (at rising edge on MSM6585) + + TODO: + - convert to modern + - lowpass filter for MSM6585 + */ typedef struct _msm5205_state msm5205_state;