Sprinter/mame
2
0
Fork 0
mirror of https://github.com/holub/mame synced 2025-07-03 17:08:39 +03:00
Code Issues Actions 1 Packages Projects Releases Wiki Activity

ay8910.c:

Browse Source 
* Fixes mantis bugs 01767, 01769
* Corrected some comments
This commit is contained in:
Couriersud 2008-05-02 10:58:11 +00:00
parent 128bfcc4e0
commit b7880b33fa
1 changed files with 32 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
src/emu/sound/ay8910.c
View File

@ -39,8 +39,8 @@
This is backed by oscilloscope pictures from the datasheet. If a fixed volume This is backed by oscilloscope pictures from the datasheet. If a fixed volume
is set, i.e. enveloppe is disabled, the output voltage is set to 0V. Recordings is set, i.e. enveloppe is disabled, the output voltage is set to 0V. Recordings
I found on the web for gyruss indicate, that the AY-3-8910 offset should I found on the web for gyruss indicate, that the AY-3-8910 offset should
be around 1.5V. This will also make sound levels more compatible with be around 0.2V. This will also make sound levels more compatible with
user descriptions. user observations for scramble.
The Model: The Model:
5V 5V 5V 5V
@ -66,8 +66,9 @@ where used to calibrate channel mixing for the YM2149. This was done using
a least square approach using a fixed RL of 1K Ohm. a least square approach using a fixed RL of 1K Ohm.
For the AY measurements cited in e.g. openmsx as "Hacker Kay" for a single For the AY measurements cited in e.g. openmsx as "Hacker Kay" for a single
channel were taken. These were normalized to 0 ... 65535 and adapted to on channel were taken. These were normalized to 0 ... 65535 and consequently
offset of 1.5V and a VPP of 1.3V. adapted to an offset of 0.2V and a VPP of 1.3V. These measurements are in
line e.g. with the formula used by pcmenc for the volume: vol(i) = exp(i/2-7.5).
The following is documentation from the code moved here and amended to reflect The following is documentation from the code moved here and amended to reflect
the changes done: the changes done:
@ -310,7 +311,7 @@ INLINE void build_3D_table(double rl, const ay_ym_param *par, const ay_ym_param
if (normalize) if (normalize)
{ {
for (j=0; j < 32*32*32*8; j++) for (j=0; j < 32*32*32*8; j++)
tab[j] = MAX_OUTPUT * (((temp[j] - min)/(max-min)) - 0.25) * factor; tab[j] = MAX_OUTPUT * (((temp[j] - min)/(max-min))) * factor;
} }
else else
{ {