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// 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")
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