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Diffstat (limited to 'src/devices/bus/electron/elksd128.cpp')
-rw-r--r-- | src/devices/bus/electron/elksd128.cpp | 333 |
1 files changed, 333 insertions, 0 deletions
diff --git a/src/devices/bus/electron/elksd128.cpp b/src/devices/bus/electron/elksd128.cpp new file mode 100644 index 00000000000..d82186318ce --- /dev/null +++ b/src/devices/bus/electron/elksd128.cpp @@ -0,0 +1,333 @@ +// license:BSD-3-Clause +// copyright-holders:Nigel Barnes +/********************************************************************** + + ElkSD128 Electron SD Interface + + SD Card Interface, 128K Memory Expansion & Joystick Adapter + + http://ramtop-retro.uk/elksd128.html + +**********************************************************************/ + +#include "emu.h" +#include "elksd128.h" + +#include "bus/vcs_ctrl/ctrl.h" +#include "machine/spi_sdcard.h" + + +namespace { + +class electron_elksd128_device + : public device_t + , public device_electron_expansion_interface +{ +public: + electron_elksd128_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) + : device_t(mconfig, ELECTRON_ELKSD128, tag, owner, clock) + , device_electron_expansion_interface(mconfig, *this) + , m_flash(*this, "flash") + , m_sdcard(*this, "sdcard") + , m_joy(*this, "joy") + , m_romsel(0) + , m_adc_channel(0) + , m_swr_lock(0) + , m_spi_clock_state(false) + , m_spi_clock_sysclk(false) + , m_spi_clock_cycles(0) + { + } + +protected: + // device_t overrides + virtual void device_start() override ATTR_COLD; + virtual void device_reset() override ATTR_COLD; + + // optional information overrides + 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 expbus_r(offs_t offset) override; + virtual void expbus_w(offs_t offset, uint8_t data) override; + +private: + required_memory_region m_flash; + required_device<spi_sdcard_device> m_sdcard; + required_device<vcs_control_port_device> m_joy; + + uint8_t m_romsel; + uint8_t m_adc_channel; + uint8_t m_swr_lock; + + TIMER_CALLBACK_MEMBER(spi_clock); + + emu_timer *m_spi_clock; + bool m_spi_clock_state; + bool m_spi_clock_sysclk; + int m_spi_clock_cycles; + int m_in_bit; + uint8_t m_in_latch; + uint8_t m_out_latch; + + std::unique_ptr<uint8_t[]> m_ram; +}; + + +//------------------------------------------------- +// rom_region - device-specific ROM region +//------------------------------------------------- + +ROM_START( elksd128 ) + ROM_REGION(0x80000, "flash", 0) + ROM_LOAD("esd12815.rom", 0x0000, 0x80000, CRC(3ecf23ce) SHA1(d552149fec6a1deec2b75c740092bd311d67046f)) +ROM_END + +const tiny_rom_entry *electron_elksd128_device::device_rom_region() const +{ + return ROM_NAME( elksd128 ); +} + + +//------------------------------------------------- +// device_add_mconfig - add device configuration +//------------------------------------------------- + +void electron_elksd128_device::device_add_mconfig(machine_config &config) +{ + SPI_SDCARD(config, m_sdcard, 0); + m_sdcard->set_prefer_sdhc(); + m_sdcard->spi_miso_callback().set([this](int state) { m_in_bit = state; }); + + VCS_CONTROL_PORT(config, m_joy, vcs_control_port_devices, "joy"); +} + + +//------------------------------------------------- +// device_start - device-specific startup +//------------------------------------------------- + +void electron_elksd128_device::device_start() +{ + m_ram = make_unique_clear<uint8_t[]>(0x20000); + + m_spi_clock = timer_alloc(FUNC(electron_elksd128_device::spi_clock), this); + + save_item(NAME(m_romsel)); + save_item(NAME(m_adc_channel)); + save_item(NAME(m_swr_lock)); + save_pointer(NAME(m_ram), 0x20000); + save_item(NAME(m_spi_clock_state)); + save_item(NAME(m_spi_clock_sysclk)); + save_item(NAME(m_spi_clock_cycles)); + save_item(NAME(m_in_bit)); + save_item(NAME(m_in_latch)); + save_item(NAME(m_out_latch)); +} + +//------------------------------------------------- +// device_reset - device-specific startup +//------------------------------------------------- + +void electron_elksd128_device::device_reset() +{ + m_spi_clock->adjust(attotime::never); + m_spi_clock_cycles = 0; + m_spi_clock_state = false; +} + + +//------------------------------------------------- +// expbus_r - expansion data read +//------------------------------------------------- + +uint8_t electron_elksd128_device::expbus_r(offs_t offset) +{ + uint8_t data = 0xff; + + switch (offset >> 12) + { + case 0x8: case 0x9: case 0xa: case 0xb: + switch (m_romsel) + { + case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: + data = m_ram[(m_romsel) << 14 | (offset & 0x3fff)]; + break; + + case 12: + data = m_flash->base()[(m_romsel - 10) << 14 | (offset & 0x3fff)]; + break; + + case 14: case 15: + data = m_flash->base()[(m_romsel - 14) << 14 | (offset & 0x3fff)]; + break; + } + break; + + case 0xf: + switch (offset >> 8) + { + case 0xfc: + switch (offset) + { + case 0xfc70: // Plus 1 analogue/digital converter + switch (m_adc_channel) + { + case 0x04: + if (!BIT(m_joy->read_joy(), 3)) + data = 0x00; + else if (!BIT(m_joy->read_joy(), 2)) + data = 0xff; + else + data = 0x80; + break; + case 0x05: + if (!BIT(m_joy->read_joy(), 1)) + data = 0x00; + else if (!BIT(m_joy->read_joy(), 0)) + data = 0xff; + else + data = 0x80; + break; + case 0x06: + case 0x07: + data = 0x80; + break; + } + break; + + case 0xfc72: // Plus 1 joystick and ADC status + data = 0xaf | (BIT(m_joy->read_joy(), 5) << 4); + break; + + case 0xfc80: // SPI controller data port + data = m_in_latch; + break; + + case 0xfc81: // SPI controller status register + data = m_spi_clock_cycles > 0 ? 0x01 : 0x00; + break; + + case 0xfc83: // Device ID + data = 0x80; // ElkSD128 rev 1.0 + break; + + case 0xfcc0: // First Byte interface + data = bitswap<8>(m_joy->read_joy(), 7, 6, 4, 5, 3, 2, 1, 0); + break; + + case 0xfcd0: // Slogger interface + data = bitswap<8>(m_joy->read_joy(), 7, 6, 4, 5, 3, 2, 1, 0); + break; + } + break; + } + } + + return data; +} + + +//------------------------------------------------- +// expbus_w - expansion data write +//------------------------------------------------- + +void electron_elksd128_device::expbus_w(offs_t offset, uint8_t data) +{ + switch (offset >> 12) + { + case 0x8: case 0x9: case 0xa: case 0xb: + switch (m_romsel) + { + case 0: case 1: case 2: case 3: case 4: case 5: + m_ram[(m_romsel) << 14 | (offset & 0x3fff)] = data; + break; + case 6: + if (!BIT(m_swr_lock, 6) || (offset & 0x3fff) > 0x3600) + m_ram[(m_romsel) << 14 | (offset & 0x3fff)] = data; + break; + case 7: + if (BIT(m_swr_lock, 7) || (offset & 0x3fff) > 0x3600) + m_ram[(m_romsel) << 14 | (offset & 0x3fff)] = data; + break; + } + break; + + case 0xf: + switch (offset >> 8) + { + case 0xfc: + switch (offset) + { + case 0xfc70: // Plus 1 analogue/digital converter + m_adc_channel = data; + break; + + case 0xfc80: // SPI controller data port + m_out_latch = data; + m_spi_clock_cycles = 8; + + if (m_spi_clock_sysclk) // TODO: confirm fast/slow clock dividers + m_spi_clock->adjust(attotime::from_hz(16_MHz_XTAL / 2), 0, attotime::from_hz(16_MHz_XTAL / 2)); + else + m_spi_clock->adjust(attotime::from_hz(16_MHz_XTAL / 32), 0, attotime::from_hz(16_MHz_XTAL / 32)); + break; + + case 0xfc81: // SPI controller clock register + m_spi_clock_sysclk = bool(BIT(data, 0)); + break; + + case 0xfc82: // Sideways RAM lock + m_swr_lock = data; + break; + } + break; + + case 0xfe: + if ((offset == 0xfe05) && !(data & 0xf0)) + { + m_romsel = data & 0x0f; + } + break; + } + } +} + + +TIMER_CALLBACK_MEMBER(electron_elksd128_device::spi_clock) +{ + if (m_spi_clock_cycles > 0) + { + m_sdcard->spi_ss_w(1); + + if (m_spi_clock_state) + { + m_in_latch <<= 1; + m_in_latch &= ~0x01; + m_in_latch |= m_in_bit; + + m_sdcard->spi_clock_w(1); + + m_spi_clock_cycles--; + } + else + { + m_sdcard->spi_mosi_w(BIT(m_out_latch, 7)); + m_sdcard->spi_clock_w(0); + + m_out_latch <<= 1; + } + + m_spi_clock_state = !m_spi_clock_state; + } + else + { + m_spi_clock_state = false; + m_spi_clock->adjust(attotime::never); + } +} + +} // anonymous namespace + + +DEFINE_DEVICE_TYPE_PRIVATE(ELECTRON_ELKSD128, device_electron_expansion_interface, electron_elksd128_device, "electron_elksd128", "ElkSD128 Electron SD Interface") |