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bus/nes: Simplified NES-EVENT board. (#9122)
- IRQ timer now counts up and no longer latches DIP setting when initialized, i.e. DIP switches are always live. - Removed deprecated hold_irq_line().
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0kmg
GitHub
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@ -27196,6 +27196,7 @@ license:CC0
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<description>Nintendo World Championships 1990 (USA)</description>
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<year>1990</year>
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<publisher>Nintendo</publisher>
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<info name="usage" value="To play, press start on controller 2."/>
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<part name="cart" interface="nes_cart">
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<feature name="slot" value="nes_event" />
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<feature name="pcb" value="NES-EVENT" />
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@ -33,7 +33,7 @@
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DEFINE_DEVICE_TYPE(NES_EVENT, nes_event_device, "nes_event", "NES Cart Event PCB")
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nes_event_device::nes_event_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
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nes_event_device::nes_event_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
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: nes_sxrom_device(mconfig, NES_EVENT, tag, owner, clock)
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, m_dsw(*this, "DIPSW")
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, m_nwc_init(0)
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@ -47,15 +47,11 @@ nes_event_device::nes_event_device(const machine_config &mconfig, const char *ta
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void nes_event_device::device_start()
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{
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common_start();
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nes_sxrom_device::device_start();
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event_timer = timer_alloc(TIMER_EVENT);
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event_timer->adjust(attotime::never);
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timer_freq = clocks_to_attotime(1);
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save_item(NAME(m_latch));
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save_item(NAME(m_count));
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save_item(NAME(m_reg));
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save_item(NAME(m_reg_write_enable));
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save_item(NAME(m_nwc_init));
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save_item(NAME(m_timer_count));
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@ -65,16 +61,11 @@ void nes_event_device::device_start()
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void nes_event_device::pcb_reset()
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{
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m_latch = 0;
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m_count = 0;
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m_reg[0] = 0x0f;
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m_reg[1] = m_reg[2] = m_reg[3] = 0;
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m_reg_write_enable = 1;
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nes_sxrom_device::pcb_reset();
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prg32(0);
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m_nwc_init = 2;
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set_nt_mirroring(PPU_MIRROR_HORZ);
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chr8(0, CHRRAM);
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prg32(0);
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m_timer_count = 0;
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m_timer_enabled = 0;
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m_timer_on = 0;
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@ -92,7 +83,7 @@ void nes_event_device::pcb_reset()
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Games: Nintento World Championships
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MMC-1 variant with repurposed register at $a000 and a
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MMC1 variant with repurposed register at $a000 and a
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lot of discrete components
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iNES: mapper 105
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@ -109,87 +100,41 @@ void nes_event_device::set_chr()
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void nes_event_device::set_prg()
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{
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// printf("enter with %d and reg1 0x%x - reg3 0x%x\n", m_nwc_init, m_reg[1], m_reg[3]);
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// reg[1] is different from base MMC-1!
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// reg[1] is different from base MMC1!
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// bit 0 is ignored, bit1/bit3 are used for PRG switch, bit4 is used for the timer
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uint8_t temp = (m_reg[1] >> 1) & 7;
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// initially PRG is fixed, until bit4 of reg1 is set to 1 and then to 0
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switch (m_nwc_init)
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{
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case 2:
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if (m_reg[1] & 0x10) m_nwc_init--;
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if (BIT(m_reg[1], 4)) m_nwc_init--;
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return;
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case 1:
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if (~m_reg[1] & 0x10) m_nwc_init--;
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if (!BIT(m_reg[1], 4)) m_nwc_init--;
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return;
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}
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if (temp < 4)
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prg32(temp);
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// PRG mode 1 works similarly to base MMC1, but only acts on the higher 128KB (2nd PRG ROM)
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if (BIT(m_reg[1], 3))
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nes_sxrom_device::set_prg(0x08, 0x07);
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else
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{
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// else PRG works similarly to base MMC-1, but only acts on the higher 128KB (2nd PRG ROM)
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switch (m_reg[0] & 0x0c)
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{
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case 0x00:
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case 0x04:
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prg32(0x04 | ((m_reg[3] >> 1) & 0x03));
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break;
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case 0x08:
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prg16_89ab(0x08 | 0x00);
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prg16_cdef(0x08 | (m_reg[3] & 0x07));
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break;
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case 0x0c:
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prg16_89ab(0x08 | (m_reg[3] & 0x07));
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prg16_cdef(0x08 | 0x07);
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break;
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}
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}
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prg32(BIT(m_reg[1], 1, 2));
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// after the init procedure above, bit4 of m_reg[1] is used to init IRQ, by setting and then clearing the bit
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// however, there are (bankswitch related?) writes with bit4 cleared before the one 'enabling' the timer, so
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// we need the additional m_timer_enabled variable, to avoid starting the timer before its time...
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if (m_reg[1] & 0x10)
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if (BIT(m_reg[1], 4))
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{
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m_timer_count = 0;
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m_timer_enabled = 1;
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set_irq_line(CLEAR_LINE);
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}
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else
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else if (!m_timer_on && m_timer_enabled)
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{
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if (!m_timer_on && m_timer_enabled)
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{
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m_timer_count = 0x20000000 | ((m_dsw->read() & 0x0f) << 25);
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event_timer->adjust(attotime::zero, 0, timer_freq);
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m_timer_on = 1;
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}
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event_timer->adjust(attotime::zero, 0, clocks_to_attotime(1));
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m_timer_on = 1;
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}
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}
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void nes_event_device::update_regs(int reg)
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{
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switch (reg)
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{
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case 0:
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switch (m_reg[0] & 0x03)
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{
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case 0: set_nt_mirroring(PPU_MIRROR_LOW); break;
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case 1: set_nt_mirroring(PPU_MIRROR_HIGH); break;
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case 2: set_nt_mirroring(PPU_MIRROR_VERT); break;
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case 3: set_nt_mirroring(PPU_MIRROR_HORZ); break;
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}
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set_prg();
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break;
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case 1:
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set_prg();
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break;
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case 2:
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set_chr();
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break;
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case 3:
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set_prg();
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break;
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}
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}
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//-------------------------------------------------
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// Dipswitch
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@ -230,12 +175,11 @@ ioport_constructor nes_event_device::device_input_ports() const
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void nes_event_device::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr)
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{
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if (id == TIMER_EVENT)
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if (id == TIMER_EVENT && m_timer_on)
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{
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m_timer_count--;
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if (!m_timer_count)
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if (++m_timer_count >= (0x10 | m_dsw->read()) << 25)
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{
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hold_irq_line();
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set_irq_line(ASSERT_LINE);
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event_timer->reset();
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}
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}
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@ -14,20 +14,16 @@ class nes_event_device : public nes_sxrom_device
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{
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public:
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// construction/destruction
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nes_event_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
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virtual ioport_constructor device_input_ports() const override;
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nes_event_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock);
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virtual void pcb_reset() override;
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protected:
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static constexpr device_timer_id TIMER_EVENT = 0;
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// device-level overrides
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virtual void device_start() override;
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virtual void device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr) override;
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virtual ioport_constructor device_input_ports() const override;
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virtual void update_regs(int reg) override;
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virtual void set_prg() override;
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virtual void set_chr() override;
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@ -35,10 +31,10 @@ protected:
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int m_nwc_init;
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static constexpr device_timer_id TIMER_EVENT = 0;
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emu_timer *event_timer;
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attotime timer_freq;
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uint32_t m_timer_count;
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u32 m_timer_count;
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int m_timer_on, m_timer_enabled;
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};
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@ -184,7 +184,7 @@ void nes_sxrom_device::set_chr(int chr_base, int chr_mask)
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chr8((chr_base | (m_reg[1] & chr_mask)) >> 1, m_chr_source);
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}
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// this allows for easier implementation of the NES-EVENT board used for Nintento World Championships
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// this allows for easier implementation of MMC1 subclasses
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void nes_sxrom_device::update_regs(int reg)
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{
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switch (reg)
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