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Diffstat (limited to 'src/devices/bus/spectrum/vtx5000.cpp')
-rw-r--r-- | src/devices/bus/spectrum/vtx5000.cpp | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/src/devices/bus/spectrum/vtx5000.cpp b/src/devices/bus/spectrum/vtx5000.cpp new file mode 100644 index 00000000000..2c2aa36b4eb --- /dev/null +++ b/src/devices/bus/spectrum/vtx5000.cpp @@ -0,0 +1,170 @@ +// license:BSD-3-Clause +// copyright-holders:Nigel Barnes +/********************************************************************** + + Prism VTX 5000 Modem + +**********************************************************************/ + +#include "emu.h" +#include "vtx5000.h" +#include "machine/clock.h" +#include "machine/i8251.h" +#include "bus/rs232/rs232.h" + + +namespace { + +class spectrum_vtx5000_device : public device_t, public device_spectrum_expansion_interface +{ +public: + spectrum_vtx5000_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) + : device_t(mconfig, SPECTRUM_VTX5000, tag, owner, clock) + , device_spectrum_expansion_interface(mconfig, *this) + , m_exp(*this, "exp") + , m_usart(*this, "i8251") + , m_rom(*this, "rom") + { + } + +protected: + virtual void device_start() override ATTR_COLD; + virtual void device_reset() override ATTR_COLD; + + virtual void device_add_mconfig(machine_config &config) override ATTR_COLD; + virtual const tiny_rom_entry *device_rom_region() const override ATTR_COLD; + + virtual uint8_t mreq_r(offs_t offset) override; + virtual uint8_t iorq_r(offs_t offset) override; + virtual void iorq_w(offs_t offset, uint8_t data) override; + virtual bool romcs() override; + + // passthru + virtual void pre_opcode_fetch(offs_t offset) override { m_exp->pre_opcode_fetch(offset); } + virtual void post_opcode_fetch(offs_t offset) override { m_exp->post_opcode_fetch(offset); } + virtual void pre_data_fetch(offs_t offset) override { m_exp->pre_data_fetch(offset); } + virtual void post_data_fetch(offs_t offset) override { m_exp->post_data_fetch(offset); } + virtual void mreq_w(offs_t offset, uint8_t data) override { if (m_exp->romcs()) m_exp->mreq_w(offset, data); } + +private: + required_device<spectrum_expansion_slot_device> m_exp; + required_device<i8251_device> m_usart; + required_memory_region m_rom; + + bool m_romcs; +}; + + +ROM_START(vtx5000) + ROM_REGION( 0x2000, "rom", 0 ) + ROM_SYSTEM_BIOS(0, "v31mnet", "V3.1 Micronet") + ROMX_LOAD("vtx5000-3-1.rom", 0x0000, 0x2000, CRC(1431505c) SHA1(42ae2b47c44d8c0d6a6c6a2b39a4a25a6d3a4bda), ROM_BIOS(0)) + + ROM_SYSTEM_BIOS(1, "v31hlink", "V3.1 Homelink") + ROMX_LOAD("homelink.rom", 0x0000, 0x2000, CRC(527d7f32) SHA1(4490186845b198ca9191dd711bd38274cba6f04b), ROM_BIOS(1)) +ROM_END + + +const tiny_rom_entry *spectrum_vtx5000_device::device_rom_region() const +{ + return ROM_NAME(vtx5000); +} + + +//------------------------------------------------- +// device_add_mconfig - add device configuration +//------------------------------------------------- + +void spectrum_vtx5000_device::device_add_mconfig(machine_config &config) +{ + I8251(config, m_usart, 2.4576_MHz_XTAL); + m_usart->txd_handler().set("modem", FUNC(rs232_port_device::write_txd)); + m_usart->dtr_handler().set("modem", FUNC(rs232_port_device::write_dtr)); + m_usart->rts_handler().set([this](int state) { m_romcs = state; }); + + clock_device &rx_clock(CLOCK(config, "rx_clock", 2.4576_MHz_XTAL / 16 / 2)); // 1200 baud + rx_clock.signal_handler().set(m_usart, FUNC(i8251_device::write_rxc)); + + clock_device &tx_clock(CLOCK(config, "tx_clock", 2.4576_MHz_XTAL / 16 / 32)); // 75 baud + tx_clock.signal_handler().set(m_usart, FUNC(i8251_device::write_txc)); + + rs232_port_device &rs232(RS232_PORT(config, "modem", default_rs232_devices, nullptr)); // TCM3101 (internal modem) + rs232.rxd_handler().set(m_usart, FUNC(i8251_device::write_rxd)); + rs232.dcd_handler().set(m_usart, FUNC(i8251_device::write_dsr)).invert(); + + // passthru + SPECTRUM_EXPANSION_SLOT(config, m_exp, spectrum_expansion_devices, nullptr); + m_exp->irq_handler().set(DEVICE_SELF_OWNER, FUNC(spectrum_expansion_slot_device::irq_w)); + m_exp->nmi_handler().set(DEVICE_SELF_OWNER, FUNC(spectrum_expansion_slot_device::nmi_w)); + m_exp->fb_r_handler().set(DEVICE_SELF_OWNER, FUNC(spectrum_expansion_slot_device::fb_r)); +} + + +//------------------------------------------------- +// device_start - device-specific startup +//------------------------------------------------- + +void spectrum_vtx5000_device::device_start() +{ + // CTS grounded + m_usart->write_cts(0); + + save_item(NAME(m_romcs)); +} + +//------------------------------------------------- +// device_reset - device-specific reset +//------------------------------------------------- + +void spectrum_vtx5000_device::device_reset() +{ + m_romcs = 1; +} + + +//************************************************************************** +// IMPLEMENTATION +//************************************************************************** + +bool spectrum_vtx5000_device::romcs() +{ + return m_romcs || m_exp->romcs(); +} + + +uint8_t spectrum_vtx5000_device::mreq_r(offs_t offset) +{ + uint8_t data = 0xff; + + if (m_romcs) + data = m_rom->base()[offset & 0x1fff]; + + if (m_exp->romcs()) + data &= m_exp->mreq_r(offset); + + return data; +} + + +uint8_t spectrum_vtx5000_device::iorq_r(offs_t offset) +{ + uint8_t data = m_exp->iorq_r(offset); + + if ((offset & 0x7f) == 0x7f) + data = m_usart->read(BIT(offset, 7)); + + return data; +} + +void spectrum_vtx5000_device::iorq_w(offs_t offset, uint8_t data) +{ + if ((offset & 0x7f) == 0x7f) + m_usart->write(BIT(offset, 7), data); + + m_exp->iorq_w(offset, data); +} + +} // anonymous namespace + + +DEFINE_DEVICE_TYPE_PRIVATE(SPECTRUM_VTX5000, device_spectrum_expansion_interface, spectrum_vtx5000_device, "spectrum_vtx5000", "Prism VTX 5000 Modem") |