diff options
Diffstat (limited to 'src/devices/cpu/m6502/gew7.cpp')
-rw-r--r-- | src/devices/cpu/m6502/gew7.cpp | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/src/devices/cpu/m6502/gew7.cpp b/src/devices/cpu/m6502/gew7.cpp new file mode 100644 index 00000000000..76e1378d9e8 --- /dev/null +++ b/src/devices/cpu/m6502/gew7.cpp @@ -0,0 +1,216 @@ +// license:BSD-3-Clause +// copyright-holders:Devin Acker +/*************************************************************************** + + gew7.cpp + + Yamaha GEW7, GEW7I, GEW7S (65c02-based) + +***************************************************************************/ + +#include "emu.h" +#include "gew7.h" + +#include "m6502mcu.ipp" + +#include "bus/generic/slot.h" + + +DEFINE_DEVICE_TYPE(GEW7, gew7_device, "gew7", "Yamaha YMW270-F (GEW7)") + +gew7_device::gew7_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) + : m6502_mcu_device_base<w65c02_device>(mconfig, GEW7, tag, owner, clock) + , device_mixer_interface(mconfig, *this) + , m_in_cb(*this, 0xff), m_out_cb(*this) + , m_rom(*this, DEVICE_SELF) + , m_bank(*this, "bank%u", 0U) + , m_pcm(*this, "pcm") +{ + program_config.m_internal_map = address_map_constructor(FUNC(gew7_device::internal_map), this); + + std::fill(std::begin(m_port_force_bits), std::end(m_port_force_bits), 0); + std::fill(std::begin(m_port_force_mask), std::end(m_port_force_mask), 0); +} + + +void gew7_device::device_add_mconfig(machine_config &config) +{ + GEW7_PCM(config, m_pcm, DERIVED_CLOCK(1, 1)); + m_pcm->set_device_rom_tag(m_rom); + m_pcm->add_route(0, *this, 1.0, 0); + m_pcm->add_route(1, *this, 1.0, 1); +} + +void gew7_device::device_start() +{ + m6502_mcu_device_base<w65c02_device>::device_start(); + + m_bank_mask = device_generic_cart_interface::map_non_power_of_two( + unsigned(m_rom->bytes() >> 14), + [this, base = &m_rom->as_u8()] (unsigned entry, unsigned page) + { + m_bank[0]->configure_entry(entry, &base[page << 14]); + m_bank[1]->configure_entry(entry, &base[page << 14]); + }); + + m_timer_base[0] = m_timer_base[1] = 0; + + std::fill(std::begin(m_port_data), std::end(m_port_data), 0); + std::fill(std::begin(m_port_ddr), std::end(m_port_ddr), 0); + + save_item(NAME(m_timer_stat)); + save_item(NAME(m_timer_en)); + save_item(NAME(m_timer_count)); + save_item(NAME(m_timer_base)); + save_item(NAME(m_port_data)); + save_item(NAME(m_port_ddr)); +} + +void gew7_device::device_reset() +{ + m6502_mcu_device_base<w65c02_device>::device_reset(); + + internal_update(); + m_timer_stat = m_timer_en = 0; + m_timer_count[0] = m_timer_count[1] = 0; + internal_update(); +} + + +void gew7_device::internal_map(address_map &map) +{ + map(0x0000, 0x005f).rw(m_pcm, FUNC(gew7_pcm_device::read), FUNC(gew7_pcm_device::write)); + map(0x0060, 0x00ff).mirror(0x0100).ram(); + map(0x0200, 0x022f).rw(m_pcm, FUNC(gew7_pcm_device::read_hi), FUNC(gew7_pcm_device::write_hi)); + map(0x0230, 0x023f).ram(); + + map(0x0400, 0x0400).rw(FUNC(gew7_device::timer_stat_r), FUNC(gew7_device::timer_stat_w)); + map(0x0401, 0x0401).w(FUNC(gew7_device::timer_en_w)); + map(0x0402, 0x0405).rw(FUNC(gew7_device::timer_count_r), FUNC(gew7_device::timer_count_w)); + map(0x0408, 0x0409).w(FUNC(gew7_device::bank_w)); + map(0x040a, 0x040f).rw(FUNC(gew7_device::port_r), FUNC(gew7_device::port_w)); + map(0x0410, 0x0415).rw(FUNC(gew7_device::port_ddr_r), FUNC(gew7_device::port_ddr_w)); + + map(0x4000, 0x7fff).bankr(m_bank[0]); + map(0x8000, 0xbfff).bankr(m_bank[1]); + map(0xc000, 0xffff).rom().region(DEVICE_SELF, 0); +} + + +void gew7_device::internal_update(u64 current_time) +{ + u64 event_time(0U); + add_event(event_time, timer_update(0, current_time)); + add_event(event_time, timer_update(1, current_time)); + recompute_bcount(event_time); +} + +u8 gew7_device::timer_stat_r() +{ + internal_update(); + return m_timer_stat; +} + +void gew7_device::timer_stat_w(u8 data) +{ + internal_update(); + m_timer_stat &= ~data; + + if (!(m_timer_stat & 3)) + set_input_line(W65C02_IRQ_LINE, CLEAR_LINE); + internal_update(); +} + +void gew7_device::timer_en_w(u8 data) +{ + internal_update(); + m_timer_en = data; + internal_update(); +} + +u8 gew7_device::timer_count_r(offs_t offset) +{ + const unsigned timer = offset >> 1; + + internal_update(); + if (!BIT(offset, 0)) + return m_timer_count[timer]; + else + return m_timer_count[timer] >> 8; +} + +void gew7_device::timer_count_w(offs_t offset, u8 data) +{ + const unsigned timer = offset >> 1; + + internal_update(); + if (!BIT(offset, 0)) + m_timer_count[timer] = (m_timer_count[timer] & 0xff00) | data; + else + m_timer_count[timer] = (m_timer_count[timer] & 0x00ff) | (data << 8); + internal_update(); +} + +u64 gew7_device::timer_update(int num, u64 current_time) +{ + static constexpr unsigned tick_rate = 48; + + const u64 ticks = current_time / tick_rate; + const u64 elapsed = ticks - m_timer_base[num]; + m_timer_base[num] = ticks; + + if (!BIT(m_timer_en, num)) + return 0; // timer disabled + + if (elapsed > m_timer_count[num]) + { + m_timer_stat |= (1 << num); + set_input_line(W65C02_IRQ_LINE, ASSERT_LINE); + } + + m_timer_count[num] -= elapsed; + + return (m_timer_base[num] + m_timer_count[num] + 1) * tick_rate; +} + + +void gew7_device::bank_w(offs_t offset, u8 data) +{ + m_bank[offset]->set_entry(data & m_bank_mask); +} + + +void gew7_device::port_force_bits(offs_t num, u8 bits, u8 mask) +{ + // Evidently (at least on the original YMW270F), tying a port pin to +5V or ground is expected + // to affect the value read from the port even when the pin is configured as output. + // PSS-11, PSS-21, PSS-31, and PSR-75 (which all use the same ROM) all rely on this in order to + // correctly detect what model they are. + m_port_force_bits[num] = bits; + m_port_force_mask[num] = mask; +} + +u8 gew7_device::port_r(offs_t offset) +{ + const u8 out_data = m_port_data[offset] & m_port_ddr[offset]; + const u8 in_data = m_in_cb[offset]() & ~m_port_ddr[offset]; + + return ((out_data | in_data) & ~m_port_force_mask[offset]) | m_port_force_bits[offset]; +} + +void gew7_device::port_w(offs_t offset, u8 data) +{ + m_port_data[offset] = data; + m_out_cb[offset](0, m_port_data[offset], m_port_ddr[offset]); +} + +u8 gew7_device::port_ddr_r(offs_t offset) +{ + return m_port_ddr[offset]; +} + +void gew7_device::port_ddr_w(offs_t offset, u8 data) +{ + m_port_ddr[offset] = data; + m_out_cb[offset](0, m_port_data[offset], m_port_ddr[offset]); +} |