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ym3802: added preliminary MIDI clock timer and click counter, gets Mahou Daisakusen (x68k) to play MIDI music.

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This commit is contained in:
mahlemiut 2017-06-24 12:45:01 +12:00
parent 97889a232f
commit 478e222886
2 changed files with 68 additions and 9 deletions
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68
src/devices/machine/ym3802.cpp
View File

@ -8,8 +8,8 @@
* - Transmit Idle detection
* - IRx/ITx (used for MIDI system messages)
* - FSK modulation
* - Timers
* - Interrupts (except for Tx Buffer Empty)
* - Timers (MIDI clock timer and Click counter are working but not guaranteed to be perfectly accurate)
* - Interrupts (except for Tx Buffer Empty, MIDI clock detect, Click Counter)
*/
#include "emu.h"
@ -39,7 +39,8 @@ void ym3802_device::device_start()
m_txd_handler.resolve_safe();
m_rxd_handler.resolve_safe(0xff);
m_clock_timer = timer_alloc(TIMER_SYSTEM_CLOCK);
m_midi_timer = timer_alloc(TIMER_MIDI_CLOCK);
m_midi_timer = timer_alloc(TIMER_TX_CLOCK);
m_midi_counter_timer = timer_alloc(TIMER_MIDI_CLOCK);
save_item(NAME(m_reg));
}
@ -58,9 +59,12 @@ void ym3802_device::device_timer(emu_timer &timer, device_timer_id id, int param
// TODO: support clock and timers
switch(id)
{
case TIMER_MIDI_CLOCK:
case TIMER_TX_CLOCK:
transmit_clk();
break;
case TIMER_MIDI_CLOCK:
midi_clk();
break;
}
}
@ -112,10 +116,35 @@ void ym3802_device::transmit_clk()
}
}
void ym3802_device::midi_clk()
{
if(m_midi_counter_base > 1) // counter is not guaranteed to work if set to 0 or 1.
{
if(m_midi_counter == 0)
{
m_midi_counter = m_midi_counter_base; // reload timer
if(m_reg[REG_IMR] & 0x08) // if IRQ1 is set to MIDI clock detect
set_irq(IRQ_MIDI_CLK);
if(m_click_counter_base != 0)
{
m_click_counter--;
if(m_click_counter == 0)
{
m_click_counter = m_click_counter_base;
if(!(m_reg[REG_IMR] & 0x08)) // if IRQ1 is set to click counter
set_irq(IRQ_CLICK);
}
}
}
else
m_midi_counter--;
}
}
void ym3802_device::reset_midi_timer()
{
uint64_t rate;
uint8_t divisor = m_reg[REG_RRR] & 0x1f;
uint8_t divisor = m_reg[REG_TRR] & 0x1f;
if(!(divisor & 0x10))
{
@ -221,11 +250,28 @@ WRITE8_MEMBER(ym3802_device::write)
switch(offset + (bank * 10))
{
case REG_IOR:
popmessage("IOR vector write %02\n",data);
logerror("IOR vector write %02\n",data);
break;
case REG_IER:
logerror("IER set to %02x\n",data);
break;
case REG_DCR:
if(data & 0x20)
{
if((data & 0x07) == 2)
{
uint64_t rate = (m_reg[REG_CCR] & 0x02) ? m_clkm_rate / 4 : m_clkm_rate / 8;
// start message to click counter
m_midi_counter_timer->adjust(attotime::from_hz(rate),0,attotime::from_hz(rate));
}
if((data & 0x07) == 3)
{
// stop message to click counter
m_midi_counter_timer->adjust(attotime::zero,0,attotime::never);
}
}
break;
case REG_TMR:
set_comms_mode();
break;
@ -246,13 +292,19 @@ WRITE8_MEMBER(ym3802_device::write)
//popmessage("General counter set to %i\n",m_general_counter);
break;
case REG_MTR_LOW:
m_midi_counter = (m_midi_counter & 0xff00) | data;
m_midi_counter_base = (m_midi_counter & 0xff00) | data;
m_midi_counter = m_midi_counter_base;
//popmessage("MIDI counter set to %i\n",m_midi_counter);
break;
case REG_MTR_HIGH:
m_midi_counter = (m_midi_counter & 0x00ff) | ((data & 0x3f) << 8);
m_midi_counter_base = (m_midi_counter & 0x00ff) | ((data & 0x3f) << 8);
m_midi_counter = m_midi_counter_base;
//popmessage("MIDI counter set to %i\n",m_midi_counter);
break;
case REG_CDR:
m_click_counter_base = data & 0x7f;
m_click_counter = m_click_counter_base;
break;
}
}
}

9
src/devices/machine/ym3802.h
View File

@ -126,10 +126,12 @@ private:
enum
{
TIMER_SYSTEM_CLOCK = 0x200, // CLK input - anywhere from 1MHz up to 4MHz
TIMER_MIDI_CLOCK, // CLKM input - usually either 1MHz or 0.5MHz, or CLKF input - usually 614.4kHz
TIMER_TX_CLOCK,
TIMER_MIDI_CLOCK // CLKM input - usually either 1MHz or 0.5MHz, or CLKF input - usually 614.4kHz
};
void transmit_clk();
void midi_clk();
void reset_midi_timer();
void set_comms_mode();
void set_irq(uint8_t irq);
@ -140,6 +142,7 @@ private:
devcb_read_line m_rxd_handler;
emu_timer* m_clock_timer;
emu_timer* m_midi_timer;
emu_timer* m_midi_counter_timer;
std::vector<uint8_t> m_reg;
uint8_t m_wdr;
@ -147,6 +150,10 @@ private:
uint8_t m_irq_status;
uint16_t m_general_counter;
uint16_t m_midi_counter;
uint16_t m_midi_counter_base;
uint8_t m_midi_counter_divider;
uint8_t m_click_counter;
uint8_t m_click_counter_base;
uint8_t m_vector;
std::queue<uint8_t> m_tx_fifo;