diff options
Diffstat (limited to 'src/devices/bus/pc8801/pcg8100.cpp')
-rw-r--r-- | src/devices/bus/pc8801/pcg8100.cpp | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/src/devices/bus/pc8801/pcg8100.cpp b/src/devices/bus/pc8801/pcg8100.cpp new file mode 100644 index 00000000000..c2bf07c7f73 --- /dev/null +++ b/src/devices/bus/pc8801/pcg8100.cpp @@ -0,0 +1,109 @@ +// license:BSD-3-Clause +// copyright-holders:Angelo Salese +/************************************************************************************************** + + HAL PCG-8100 + + Used on a bunch of PC-8001 games, adds a Programmable Character Generator overlay, + a write-only 8253 with channels tied to three DAC1BIT + +**************************************************************************************************/ + +#include "emu.h" +#include "pcg8100.h" + + +DEFINE_DEVICE_TYPE(PCG8100, pcg8100_device, "pcg8100", "HAL Laboratory PCG-8100") + +pcg8100_device::pcg8100_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) + : pc8801_exp_device(mconfig, PCG8100, tag, owner, clock) + , m_pit(*this, "pit") + , m_dac1bit(*this, "dac1bit%u", 0L) + , m_cg_rom(*this, "^^cgrom") +{ +} + +void pcg8100_device::io_map(address_map &map) +{ + map(0x00, 0x00).lw8(NAME([this] (u8 data) { m_pcg_data = data; })); + map(0x01, 0x01).lw8(NAME([this] (u8 data) { m_pcg_address = (m_pcg_address & 0x300) | data; })); + map(0x02, 0x02).w(FUNC(pcg8100_device::pcg_latch_w)); + map(0x0c, 0x0f).w(m_pit, FUNC(pit8253_device::write)); +} + +void pcg8100_device::device_add_mconfig(machine_config &config) +{ + constexpr XTAL pcg_clock = XTAL(31'948'800) / 8; + + PIT8253(config, m_pit, 0); + m_pit->set_clk<0>(pcg_clock); + m_pit->out_handler<0>().set(m_dac1bit[0], FUNC(speaker_sound_device::level_w)); + m_pit->set_clk<1>(pcg_clock); + m_pit->out_handler<1>().set(m_dac1bit[1], FUNC(speaker_sound_device::level_w)); + m_pit->set_clk<2>(pcg_clock); + m_pit->out_handler<2>().set(m_dac1bit[2], FUNC(speaker_sound_device::level_w)); + + for (auto &dac1bit : m_dac1bit) + { + SPEAKER_SOUND(config, dac1bit); + dac1bit->add_route(ALL_OUTPUTS, "^^lspeaker", 0.25); + dac1bit->add_route(ALL_OUTPUTS, "^^rspeaker", 0.25); + } +} + +void pcg8100_device::device_start() +{ + save_item(NAME(m_pcg_data)); + save_item(NAME(m_pcg_address)); + + // PCG overlays directly to the internal PC-8001 3301 CG ROM base. + // Save a local copy of the original data here, card can eventually restore data at later time. + for (int i = 0x000; i < 0x400; i++) + m_original_rom[i] = m_cg_rom[i | 0x400]; + + save_item(NAME(m_original_rom)); +} + +void pcg8100_device::device_reset() +{ + int i; + m_pcg_data = 0; + m_pcg_address = 0; + m_pcg_latch = 0; + + for (i = 0x000; i < 0x400; i++) + m_cg_rom[i | 0x400] = m_original_rom[i]; + + for (i = 0; i < 3; i++) + audio_channel(i, false); +} + +void pcg8100_device::audio_channel(u8 ch, bool keyon) +{ + m_dac1bit[ch]->set_output_gain(0, keyon ? 1.0 : 0.0); +} + +/* + * x--- ---- DAC1BIT #2 + * -x-- ---- DAC1BIT #1 + * --x- ---- (0) select overlay on latch (1) select PC-8001/PC-8801 original CG ROM + * ---x ---- latch data into current PCG address RAM + * ---- x--- DAC1BIT #0 + * ---- --xx upper PCG address + */ +void pcg8100_device::pcg_latch_w(u8 data) +{ + if (BIT(m_pcg_latch, 4) && !(BIT(data, 4))) + { + if (BIT(m_pcg_latch, 5)) + m_cg_rom[0x400 | m_pcg_address] = m_original_rom[m_pcg_address]; + else + m_cg_rom[0x400 | m_pcg_address] = m_pcg_data; + } + m_pcg_address = (m_pcg_address & 0xff) | ((data & 0x3) << 8); + m_pcg_latch = data; + + audio_channel(0, bool(BIT(data, 3))); + audio_channel(1, bool(BIT(data, 6))); + audio_channel(2, bool(BIT(data, 7))); +} |