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pc9801_86.cpp : Fix pcm timer rate, Add notes [cam900]

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cam900 2018-04-13 23:22:00 +09:00 committed by cracyc
parent 3376e628e1
commit 6e63cc41f3
1 changed files with 3 additions and 2 deletions
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5
src/devices/bus/cbus/pc9801_86.cpp
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@ -252,7 +252,8 @@ READ8_MEMBER(pc9801_86_device::pcm_r)
WRITE8_MEMBER(pc9801_86_device::pcm_w) WRITE8_MEMBER(pc9801_86_device::pcm_w)
{ {
const int rates[] = {44100, 33075, 22050, 16538, 11025, 8268, 5513, 4134}; const int rate = 44100*3; // TODO : unknown clock / divider
const int divs[8] = {3, 4, 6, 8, 12, 16, 24, 32};
if((offset & 1) == 0) if((offset & 1) == 0)
{ {
switch(offset >> 1) switch(offset >> 1)
@ -263,7 +264,7 @@ WRITE8_MEMBER(pc9801_86_device::pcm_w)
case 2: case 2:
m_pcm_ctrl = data & ~0x10; m_pcm_ctrl = data & ~0x10;
if(data & 0x80) if(data & 0x80)
m_dac_timer->adjust(attotime::from_hz(rates[data & 7]), 0, attotime::from_hz(rates[data & 7])); m_dac_timer->adjust(attotime::from_ticks(divs[data & 7], rate), 0, attotime::from_ticks(divs[data & 7], rate));
else else
m_dac_timer->adjust(attotime::never); m_dac_timer->adjust(attotime::never);
if(data & 8) if(data & 8)