src/serial/MSXRS232.cc at main · doomsdayone/openmsx

◆ main openmsx / src / serial / MSXRS232.cc

12.1 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw

#include "MSXRS232.hh"

#include "RS232Device.hh"

#include "BooleanSetting.hh"
#include "CacheLine.hh"
#include "MSXException.hh"
#include "Ram.hh"
#include "Rom.hh"
#include "serialize.hh"

#include "one_of.hh"
#include "outer.hh"
#include "unreachable.hh"

#include <cassert>
#include <memory>

namespace openmsx {

const unsigned RAM_OFFSET = 0x2000;
const unsigned RAM_SIZE = 0x800;

MSXRS232::MSXRS232(DeviceConfig& config)
	: MSXDevice(config)
	, RS232Connector(MSXDevice::getPluggingController(), "msx-rs232")
	, i8254(getScheduler(), &cntr0, &cntr1, nullptr, getCurrentTime())
	, i8251(getScheduler(), interface, getCurrentTime())
	, rom(config.findChild("rom")
		? std::make_unique<Rom>(
			MSXDevice::getName() + " ROM", "rom", config)
		: nullptr) // when the ROM is already mapped, you don't want to specify it again here
	, ram(config.getChildDataAsBool("ram", false)
		? std::make_unique<Ram>(
			config, MSXDevice::getName() + " RAM",
	                "RS232 RAM", RAM_SIZE)
		: nullptr)
	, rxrdyIRQ(getMotherBoard(), MSXDevice::getName() + ".IRQrxrdy")
	, hasMemoryBasedIo(config.getChildDataAsBool("memorybasedio", false))
	, hasRIPin(config.getChildDataAsBool("has_ri_pin", true))
	, inputsPullup(config.getChildDataAsBool("rs232_pullup",false))
	, ioAccessEnabled(!hasMemoryBasedIo)
	, switchSetting(config.getChildDataAsBool("toshiba_rs232c_switch",
		false) ? std::make_unique<BooleanSetting>(getCommandController(),
		"toshiba_rs232c_switch", "status of the RS-232C enable switch",
		true) : nullptr)
{
	if (rom && (rom->size() != one_of(0x2000u, 0x4000u))) {
		throw MSXException("RS232C only supports 8kB or 16kB ROMs.");
	}

	EmuDuration total = EmuDuration::hz(1.8432e6); // 1.8432MHz
	EmuDuration hi    = EmuDuration::hz(3.6864e6); //   half clock period
	EmuTime time = getCurrentTime();
	i8254.getClockPin(0).setPeriodicState(total, hi, time);
	i8254.getClockPin(1).setPeriodicState(total, hi, time);
	i8254.getClockPin(2).setPeriodicState(total, hi, time);

	powerUp(time);
}

MSXRS232::~MSXRS232() = default;

void MSXRS232::notifyBaudRate()
{
	auto& dev = getPluggedRS232Dev();
	const ClockPin& clk = i8251.getClockPin();
	if (clk.isPeriodic()) {
		auto period = clk.getTotalDuration().toUint64();
		if (period > 0) {
			unsigned factor = i8251.getBaudRateFactor();
			auto baud = static_cast<unsigned>(MAIN_FREQ / (period * factor));
			dev.setBaudRate(baud);
		}
	}
}

void MSXRS232::powerUp(EmuTime time)
{
	if (ram) ram->clear();
	reset(time);
}

void MSXRS232::reset(EmuTime /*time*/)
{
	rxrdyIRQlatch = false;
	rxrdyIRQenabled = false;
	rxrdyIRQ.reset();

	ioAccessEnabled = !hasMemoryBasedIo;

	if (ram) ram->clear();
}

uint8_t MSXRS232::readMem(uint16_t address, EmuTime time)
{
	if (hasMemoryBasedIo && (0xBFF8 <= address) && (address <= 0xBFFF)) {
		return readIOImpl(address & 0x07, time);
	}
	uint16_t addr = address & 0x3FFF;
	if (ram && ((RAM_OFFSET <= addr) && (addr < (RAM_OFFSET + RAM_SIZE)))) {
		return (*ram)[addr - RAM_OFFSET];
	} else if (rom && (0x4000 <= address) && (address < 0x8000)) {
		return (*rom)[addr & (rom->size() - 1)];
	} else {
		return 0xFF;
	}
}

const uint8_t* MSXRS232::getReadCacheLine(uint16_t start) const
{
	if (hasMemoryBasedIo && (start == (0xBFF8 & CacheLine::HIGH))) {
		return nullptr;
	}
	uint16_t addr = start & 0x3FFF;
	if (ram && ((RAM_OFFSET <= addr) && (addr < (RAM_OFFSET + RAM_SIZE)))) {
		return &(*ram)[addr - RAM_OFFSET];
	} else if (rom && (0x4000 <= start) && (start < 0x8000)) {
		return &(*rom)[addr & (rom->size() - 1)];
	} else {
		return unmappedRead.data();
	}
}

void MSXRS232::writeMem(uint16_t address, uint8_t value, EmuTime time)
{

	if (hasMemoryBasedIo && (0xBFF8 <= address) && (address <= 0xBFFF)) {
		// when the interface has memory based I/O, the I/O port
		// based I/O is disabled, but it can be enabled by writing
		// bit 4 to 0xBFFA. It is disabled again at reset.
		// Source: Sony HB-G900P and Sony HB-G900AP service manuals.
		// We assume here you can also disable it by writing 0 to it.
		if (address == 0xBFFA) {
			ioAccessEnabled = (value & (1 << 4))!=0;
		}
		writeIOImpl(address & 0x07, value, time);
		return;
	}
	uint16_t addr = address & 0x3FFF;
	if (ram && ((RAM_OFFSET <= addr) && (addr < (RAM_OFFSET + RAM_SIZE)))) {
		(*ram)[addr - RAM_OFFSET] = value;
	}
}

uint8_t* MSXRS232::getWriteCacheLine(uint16_t start)
{
	if (hasMemoryBasedIo && (start == (0xBFF8 & CacheLine::HIGH))) {
		return nullptr;
	}
	uint16_t addr = start & 0x3FFF;
	if (ram && ((RAM_OFFSET <= addr) && (addr < (RAM_OFFSET + RAM_SIZE)))) {
		return &(*ram)[addr - RAM_OFFSET];
	} else {
		return unmappedWrite.data();
	}
}

bool MSXRS232::allowUnaligned() const
{
	// OK, because this device doesn't call any 'fillDeviceXXXCache()'functions.
	return true;
}

uint8_t MSXRS232::readIO(uint16_t port, EmuTime time)
{
	if (ioAccessEnabled) {
		return readIOImpl(port & 0x07, time);
	}
	return 0xFF;
}

uint8_t MSXRS232::readIOImpl(uint16_t port, EmuTime time)
{
	switch (port) {
		case 0: // UART data register
		case 1: // UART status register
			return i8251.readIO(port, time);
		case 2: // Status sense port
			return readStatus(time);
		case 3: // no function
			return 0xFF;
		case 4: // counter 0 data port
		case 5: // counter 1 data port
		case 6: // counter 2 data port
		case 7: // timer command register
			return i8254.readIO(port - 4, time);
		default:
			UNREACHABLE;
	}
}

uint8_t MSXRS232::peekIO(uint16_t port, EmuTime time) const
{
	if (hasMemoryBasedIo && !ioAccessEnabled) return 0xFF;
	port &= 0x07;
	switch (port) {
		case 0: // UART data register
		case 1: // UART status register
			return i8251.peekIO(port, time);
		case 2: // Status sense port
			return 0; // TODO not implemented
		case 3: // no function
			return 0xFF;
		case 4: // counter 0 data port
		case 5: // counter 1 data port
		case 6: // counter 2 data port
		case 7: // timer command register
			return i8254.peekIO(port - 4, time);
		default:
			UNREACHABLE;
	}
}

void MSXRS232::writeIO(uint16_t port, uint8_t value, EmuTime time)
{
	if (ioAccessEnabled) writeIOImpl(port & 0x07, value, time);
}

void MSXRS232::writeIOImpl(uint16_t port, uint8_t value, EmuTime time)
{
	switch (port) {
		case 0: // UART data register
		case 1: // UART command register
			i8251.writeIO(port, value, time);
			break;
		case 2: // interrupt mask register
			setIRQMask(value);
			break;
		case 3: // no function
			break;
		case 4: // counter 0 data port
		case 5: // counter 1 data port
		case 6: // counter 2 data port
		case 7: // timer command register
			i8254.writeIO(port - 4, value, time);
			break;
	}
}

uint8_t MSXRS232::readStatus(EmuTime time)
{

	// Info from http://nocash.emubase.de/portar.htm
	//
	//  Bit Name  Expl.
	//  0   CD    Carrier Detect   (0=Active, 1=Not active)
	//  1   RI    Ring Indicator   (0=Active, 1=Not active)
	//            (Not connected on many RS232 BIOS v1 implementations)
	//  6         Timer Output from i8253 Counter 2
	//  7   CTS   Clear to Send    (0=Active, 1=Not active)
	//
	// On Toshiba HX-22, see
	//   http://www.msx.org/forum/msx-talk/hardware/toshiba-hx-22?page=3
	//   RetroTechie's post of 20-09-2012, 08:08
	//   ... The "RS-232 interrupt disable" bit can be read back via bit 3
	//   on this I/O port, if CN1 is open. If CN1 is closed, it always
	//   reads back as "0". ...

	uint8_t result = 0xFF; // Start with 0xFF, open lines on the data bus pull to 1
	const auto& dev = getPluggedRS232Dev();

	// Mask out (active low) bits
	if (dev.getDCD(time).value_or(inputsPullup)) result &= ~0x01;
	if (hasRIPin && (dev.getRI(time).value_or(inputsPullup))) result &= ~0x02;
	if (rxrdyIRQenabled && switchSetting && switchSetting->getBoolean()) result &= ~0x08;
	if (i8254.getOutputPin(2).getState(time)) result &= ~0x40;
	if (interface.getCTS(time)) result &= ~0x80;

	return result;
}

void MSXRS232::setIRQMask(uint8_t value)
{
	enableRxRDYIRQ(!(value & 1));
}

void MSXRS232::setRxRDYIRQ(bool status)
{
	if (rxrdyIRQlatch != status) {
		rxrdyIRQlatch = status;
		if (rxrdyIRQenabled) {
			if (rxrdyIRQlatch) {
				rxrdyIRQ.set();
			} else {
				rxrdyIRQ.reset();
			}
		}
	}
}

void MSXRS232::enableRxRDYIRQ(bool enabled)
{
	if (rxrdyIRQenabled != enabled) {
		rxrdyIRQenabled = enabled;
		if (!rxrdyIRQenabled && rxrdyIRQlatch) {
			rxrdyIRQ.reset();
		}
	}
}


// I8251Interface  (pass calls from I8251 to outConnector)

void MSXRS232::Interface::setRxRDY(bool status, EmuTime /*time*/)
{
	auto& rs232 = OUTER(MSXRS232, interface);
	rs232.setRxRDYIRQ(status);
}

void MSXRS232::Interface::setDTR(bool status, EmuTime time)
{
	const auto& rs232 = OUTER(MSXRS232, interface);
	rs232.getPluggedRS232Dev().setDTR(status, time);
}

void MSXRS232::Interface::setRTS(bool status, EmuTime time)
{
	const auto& rs232 = OUTER(MSXRS232, interface);
	rs232.getPluggedRS232Dev().setRTS(status, time);
}

bool MSXRS232::Interface::getDSR(EmuTime time)
{
	const auto& rs232 = OUTER(MSXRS232, interface);
	return rs232.getPluggedRS232Dev().getDSR(time).value_or(rs232.inputsPullup);
}

bool MSXRS232::Interface::getCTS(EmuTime time)
{
	const auto& rs232 = OUTER(MSXRS232, interface);
	return rs232.getPluggedRS232Dev().getCTS(time).value_or(rs232.inputsPullup);
}

void MSXRS232::Interface::setDataBits(DataBits bits)
{
	const auto& rs232 = OUTER(MSXRS232, interface);
	rs232.getPluggedRS232Dev().setDataBits(bits);
}

void MSXRS232::Interface::setStopBits(StopBits bits)
{
	const auto& rs232 = OUTER(MSXRS232, interface);
	rs232.getPluggedRS232Dev().setStopBits(bits);
}

void MSXRS232::Interface::setParityBit(bool enable, Parity parity)
{
	const auto& rs232 = OUTER(MSXRS232, interface);
	rs232.getPluggedRS232Dev().setParityBit(enable, parity);
}

void MSXRS232::Interface::recvByte(uint8_t value, EmuTime time)
{
	const auto& rs232 = OUTER(MSXRS232, interface);
	rs232.getPluggedRS232Dev().recvByte(value, time);
}

void MSXRS232::Interface::signal(EmuTime time)
{
	const auto& rs232 = OUTER(MSXRS232, interface);
	rs232.getPluggedRS232Dev().signal(time); // for input
}


// Counter 0 output

void MSXRS232::Counter0::signal(ClockPin& pin, EmuTime time)
{
	auto& rs232 = OUTER(MSXRS232, cntr0);
	ClockPin& clk = rs232.i8251.getClockPin();
	if (pin.isPeriodic()) {
		clk.setPeriodicState(pin.getTotalDuration(),
		                     pin.getHighDuration(), time);
	} else {
		clk.setState(pin.getState(time), time);
	}
	rs232.notifyBaudRate();
}

void MSXRS232::Counter0::signalPosEdge(ClockPin& /*pin*/, EmuTime /*time*/)
{
	UNREACHABLE;
}


// Counter 1 output // TODO split rx tx

void MSXRS232::Counter1::signal(ClockPin& pin, EmuTime time)
{
	auto& rs232 = OUTER(MSXRS232, cntr1);
	ClockPin& clk = rs232.i8251.getClockPin();
	if (pin.isPeriodic()) {
		clk.setPeriodicState(pin.getTotalDuration(),
		                     pin.getHighDuration(), time);
	} else {
		clk.setState(pin.getState(time), time);
	}
	rs232.notifyBaudRate();
}

void MSXRS232::Counter1::signalPosEdge(ClockPin& /*pin*/, EmuTime /*time*/)
{
	UNREACHABLE;
}


// RS232Connector input

bool MSXRS232::ready()
{
	return i8251.isRecvReady() && !i8251.isRecvFull();
}

bool MSXRS232::acceptsData()
{
	return i8251.isRecvEnabled();
}

void MSXRS232::setDataBits(DataBits bits)
{
	i8251.setDataBits(bits);
}

void MSXRS232::setStopBits(StopBits bits)
{
	i8251.setStopBits(bits);
}

void MSXRS232::setParityBit(bool enable, Parity parity)
{
	i8251.setParityBit(enable, parity);
}

void MSXRS232::recvByte(uint8_t value, EmuTime time)
{
	i8251.recvByte(value, time);
}

// version 1: initial version
// version 2: added ioAccessEnabled
// TODO: serialize switch status?
template<typename Archive>
void MSXRS232::serialize(Archive& ar, unsigned version)
{
	ar.template serializeBase<MSXDevice>(*this);
	ar.template serializeBase<RS232Connector>(*this);

	ar.serialize("I8254", i8254,
	             "I8251", i8251);
	if (ram) ar.serialize("ram", *ram);
	ar.serialize("rxrdyIRQ",        rxrdyIRQ,
	             "rxrdyIRQlatch",   rxrdyIRQlatch,
	             "rxrdyIRQenabled", rxrdyIRQenabled);
	if (ar.versionAtLeast(version, 2)) {
		ar.serialize("ioAccessEnabled", ioAccessEnabled);
	} else {
		assert(Archive::IS_LOADER);
		ioAccessEnabled = !hasMemoryBasedIo; // we can't know the
					// actual value, but this is probably
					// safest
	}

	// don't serialize cntr0, cntr1, interface
}
INSTANTIATE_SERIALIZE_METHODS(MSXRS232);
REGISTER_MSXDEVICE(MSXRS232, "RS232");

} // namespace openmsx

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e8555c89 Andy McCall 1 month ago	1	#include "MSXRS232.hh"
	2
	3	#include "RS232Device.hh"
	4
	5	#include "BooleanSetting.hh"
	6	#include "CacheLine.hh"
	7	#include "MSXException.hh"
	8	#include "Ram.hh"
	9	#include "Rom.hh"
	10	#include "serialize.hh"
	11
	12	#include "one_of.hh"
	13	#include "outer.hh"
	14	#include "unreachable.hh"
	15
	16	#include <cassert>
	17	#include <memory>
	18
	19	namespace openmsx {
	20
	21	const unsigned RAM_OFFSET = 0x2000;
	22	const unsigned RAM_SIZE = 0x800;
	23
	24	MSXRS232::MSXRS232(DeviceConfig& config)
	25	: MSXDevice(config)
	26	, RS232Connector(MSXDevice::getPluggingController(), "msx-rs232")
	27	, i8254(getScheduler(), &cntr0, &cntr1, nullptr, getCurrentTime())
	28	, i8251(getScheduler(), interface, getCurrentTime())
	29	, rom(config.findChild("rom")
	30	? std::make_unique<Rom>(
	31	MSXDevice::getName() + " ROM", "rom", config)
	32	: nullptr) // when the ROM is already mapped, you don't want to specify it again here
	33	, ram(config.getChildDataAsBool("ram", false)
	34	? std::make_unique<Ram>(
	35	config, MSXDevice::getName() + " RAM",
	36	"RS232 RAM", RAM_SIZE)
	37	: nullptr)
	38	, rxrdyIRQ(getMotherBoard(), MSXDevice::getName() + ".IRQrxrdy")
	39	, hasMemoryBasedIo(config.getChildDataAsBool("memorybasedio", false))
	40	, hasRIPin(config.getChildDataAsBool("has_ri_pin", true))
	41	, inputsPullup(config.getChildDataAsBool("rs232_pullup",false))
	42	, ioAccessEnabled(!hasMemoryBasedIo)
	43	, switchSetting(config.getChildDataAsBool("toshiba_rs232c_switch",
	44	false) ? std::make_unique<BooleanSetting>(getCommandController(),
	45	"toshiba_rs232c_switch", "status of the RS-232C enable switch",
	46	true) : nullptr)
	47	{
	48	if (rom && (rom->size() != one_of(0x2000u, 0x4000u))) {
	49	throw MSXException("RS232C only supports 8kB or 16kB ROMs.");
	50	}
	51
	52	EmuDuration total = EmuDuration::hz(1.8432e6); // 1.8432MHz
	53	EmuDuration hi = EmuDuration::hz(3.6864e6); // half clock period
	54	EmuTime time = getCurrentTime();
	55	i8254.getClockPin(0).setPeriodicState(total, hi, time);
	56	i8254.getClockPin(1).setPeriodicState(total, hi, time);
	57	i8254.getClockPin(2).setPeriodicState(total, hi, time);
	58
	59	powerUp(time);
	60	}
	61
	62	MSXRS232::~MSXRS232() = default;
	63
	64	void MSXRS232::notifyBaudRate()
65	{
66	auto& dev = getPluggedRS232Dev();
67	const ClockPin& clk = i8251.getClockPin();
68	if (clk.isPeriodic()) {
69	auto period = clk.getTotalDuration().toUint64();
70	if (period > 0) {
71	unsigned factor = i8251.getBaudRateFactor();
72	auto baud = static_cast<unsigned>(MAIN_FREQ / (period * factor));
73	dev.setBaudRate(baud);
74	}
75	}
76	}
77
78	void MSXRS232::powerUp(EmuTime time)
79	{
80	if (ram) ram->clear();
81	reset(time);
82	}
83
84	void MSXRS232::reset(EmuTime /time/)
85	{
86	rxrdyIRQlatch = false;
87	rxrdyIRQenabled = false;
88	rxrdyIRQ.reset();
89
90	ioAccessEnabled = !hasMemoryBasedIo;
91
92	if (ram) ram->clear();
93	}
94
95	uint8_t MSXRS232::readMem(uint16_t address, EmuTime time)
96	{
97	if (hasMemoryBasedIo && (0xBFF8 <= address) && (address <= 0xBFFF)) {
98	return readIOImpl(address & 0x07, time);
99	}
100	uint16_t addr = address & 0x3FFF;
101	if (ram && ((RAM_OFFSET <= addr) && (addr < (RAM_OFFSET + RAM_SIZE)))) {
102	return (*ram)[addr - RAM_OFFSET];
103	} else if (rom && (0x4000 <= address) && (address < 0x8000)) {
104	return (*rom)[addr & (rom->size() - 1)];
105	} else {
106	return 0xFF;
107	}
108	}
109
110	const uint8_t* MSXRS232::getReadCacheLine(uint16_t start) const
111	{
112	if (hasMemoryBasedIo && (start == (0xBFF8 & CacheLine::HIGH))) {
113	return nullptr;
114	}
115	uint16_t addr = start & 0x3FFF;
116	if (ram && ((RAM_OFFSET <= addr) && (addr < (RAM_OFFSET + RAM_SIZE)))) {
117	return &(*ram)[addr - RAM_OFFSET];
118	} else if (rom && (0x4000 <= start) && (start < 0x8000)) {
119	return &(*rom)[addr & (rom->size() - 1)];
120	} else {
121	return unmappedRead.data();
122	}
123	}
124
125	void MSXRS232::writeMem(uint16_t address, uint8_t value, EmuTime time)
126	{
127
128	if (hasMemoryBasedIo && (0xBFF8 <= address) && (address <= 0xBFFF)) {
129	// when the interface has memory based I/O, the I/O port
130	// based I/O is disabled, but it can be enabled by writing
131	// bit 4 to 0xBFFA. It is disabled again at reset.
132	// Source: Sony HB-G900P and Sony HB-G900AP service manuals.
133	// We assume here you can also disable it by writing 0 to it.
134	if (address == 0xBFFA) {
135	ioAccessEnabled = (value & (1 << 4))!=0;
136	}
137	writeIOImpl(address & 0x07, value, time);
138	return;
139	}
140	uint16_t addr = address & 0x3FFF;
141	if (ram && ((RAM_OFFSET <= addr) && (addr < (RAM_OFFSET + RAM_SIZE)))) {
142	(*ram)[addr - RAM_OFFSET] = value;
143	}
144	}
145
146	uint8_t* MSXRS232::getWriteCacheLine(uint16_t start)
147	{
148	if (hasMemoryBasedIo && (start == (0xBFF8 & CacheLine::HIGH))) {
149	return nullptr;
150	}
151	uint16_t addr = start & 0x3FFF;
152	if (ram && ((RAM_OFFSET <= addr) && (addr < (RAM_OFFSET + RAM_SIZE)))) {
153	return &(*ram)[addr - RAM_OFFSET];
154	} else {
155	return unmappedWrite.data();
156	}
157	}
158
159	bool MSXRS232::allowUnaligned() const
160	{
161	// OK, because this device doesn't call any 'fillDeviceXXXCache()'functions.
162	return true;
163	}
164
165	uint8_t MSXRS232::readIO(uint16_t port, EmuTime time)
166	{
167	if (ioAccessEnabled) {
168	return readIOImpl(port & 0x07, time);
169	}
170	return 0xFF;
171	}
172
173	uint8_t MSXRS232::readIOImpl(uint16_t port, EmuTime time)
174	{
175	switch (port) {
176	case 0: // UART data register
177	case 1: // UART status register
178	return i8251.readIO(port, time);
179	case 2: // Status sense port
180	return readStatus(time);
181	case 3: // no function
182	return 0xFF;
183	case 4: // counter 0 data port
184	case 5: // counter 1 data port
185	case 6: // counter 2 data port
186	case 7: // timer command register
187	return i8254.readIO(port - 4, time);
188	default:
189	UNREACHABLE;
190	}
191	}
192
193	uint8_t MSXRS232::peekIO(uint16_t port, EmuTime time) const
194	{
195	if (hasMemoryBasedIo && !ioAccessEnabled) return 0xFF;
196	port &= 0x07;
197	switch (port) {
198	case 0: // UART data register
199	case 1: // UART status register
200	return i8251.peekIO(port, time);
201	case 2: // Status sense port
202	return 0; // TODO not implemented
203	case 3: // no function
204	return 0xFF;
205	case 4: // counter 0 data port
206	case 5: // counter 1 data port
207	case 6: // counter 2 data port
208	case 7: // timer command register
209	return i8254.peekIO(port - 4, time);
210	default:
211	UNREACHABLE;
212	}
213	}
214
215	void MSXRS232::writeIO(uint16_t port, uint8_t value, EmuTime time)
216	{
217	if (ioAccessEnabled) writeIOImpl(port & 0x07, value, time);
218	}
219
220	void MSXRS232::writeIOImpl(uint16_t port, uint8_t value, EmuTime time)
221	{
222	switch (port) {
223	case 0: // UART data register
224	case 1: // UART command register
225	i8251.writeIO(port, value, time);
226	break;
227	case 2: // interrupt mask register
228	setIRQMask(value);
229	break;
230	case 3: // no function
231	break;
232	case 4: // counter 0 data port
233	case 5: // counter 1 data port
234	case 6: // counter 2 data port
235	case 7: // timer command register
236	i8254.writeIO(port - 4, value, time);
237	break;
238	}
239	}
240
241	uint8_t MSXRS232::readStatus(EmuTime time)
242	{
243
244	// Info from http://nocash.emubase.de/portar.htm
245	//
246	// Bit Name Expl.
247	// 0 CD Carrier Detect (0=Active, 1=Not active)
248	// 1 RI Ring Indicator (0=Active, 1=Not active)
249	// (Not connected on many RS232 BIOS v1 implementations)
250	// 6 Timer Output from i8253 Counter 2
251	// 7 CTS Clear to Send (0=Active, 1=Not active)
252	//
253	// On Toshiba HX-22, see
254	// http://www.msx.org/forum/msx-talk/hardware/toshiba-hx-22?page=3
255	// RetroTechie's post of 20-09-2012, 08:08
256	// ... The "RS-232 interrupt disable" bit can be read back via bit 3
257	// on this I/O port, if CN1 is open. If CN1 is closed, it always
258	// reads back as "0". ...
259
260	uint8_t result = 0xFF; // Start with 0xFF, open lines on the data bus pull to 1
261	const auto& dev = getPluggedRS232Dev();
262
263	// Mask out (active low) bits
264	if (dev.getDCD(time).value_or(inputsPullup)) result &= ~0x01;
265	if (hasRIPin && (dev.getRI(time).value_or(inputsPullup))) result &= ~0x02;
266	if (rxrdyIRQenabled && switchSetting && switchSetting->getBoolean()) result &= ~0x08;
267	if (i8254.getOutputPin(2).getState(time)) result &= ~0x40;
268	if (interface.getCTS(time)) result &= ~0x80;
269
270	return result;
271	}
272
273	void MSXRS232::setIRQMask(uint8_t value)
274	{
275	enableRxRDYIRQ(!(value & 1));
276	}
277
278	void MSXRS232::setRxRDYIRQ(bool status)
279	{
280	if (rxrdyIRQlatch != status) {
281	rxrdyIRQlatch = status;
282	if (rxrdyIRQenabled) {
283	if (rxrdyIRQlatch) {
284	rxrdyIRQ.set();
285	} else {
286	rxrdyIRQ.reset();
287	}
288	}
289	}
290	}
291
292	void MSXRS232::enableRxRDYIRQ(bool enabled)
293	{
294	if (rxrdyIRQenabled != enabled) {
295	rxrdyIRQenabled = enabled;
296	if (!rxrdyIRQenabled && rxrdyIRQlatch) {
297	rxrdyIRQ.reset();
298	}
299	}
300	}
301
302
303	// I8251Interface (pass calls from I8251 to outConnector)
304
305	void MSXRS232::Interface::setRxRDY(bool status, EmuTime /time/)
306	{
307	auto& rs232 = OUTER(MSXRS232, interface);
308	rs232.setRxRDYIRQ(status);
309	}
310
311	void MSXRS232::Interface::setDTR(bool status, EmuTime time)
312	{
313	const auto& rs232 = OUTER(MSXRS232, interface);
314	rs232.getPluggedRS232Dev().setDTR(status, time);
315	}
316
317	void MSXRS232::Interface::setRTS(bool status, EmuTime time)
318	{
319	const auto& rs232 = OUTER(MSXRS232, interface);
320	rs232.getPluggedRS232Dev().setRTS(status, time);
321	}
322
323	bool MSXRS232::Interface::getDSR(EmuTime time)
324	{
325	const auto& rs232 = OUTER(MSXRS232, interface);
326	return rs232.getPluggedRS232Dev().getDSR(time).value_or(rs232.inputsPullup);
327	}
328
329	bool MSXRS232::Interface::getCTS(EmuTime time)
330	{
331	const auto& rs232 = OUTER(MSXRS232, interface);
332	return rs232.getPluggedRS232Dev().getCTS(time).value_or(rs232.inputsPullup);
333	}
334
335	void MSXRS232::Interface::setDataBits(DataBits bits)
336	{
337	const auto& rs232 = OUTER(MSXRS232, interface);
338	rs232.getPluggedRS232Dev().setDataBits(bits);
339	}
340
341	void MSXRS232::Interface::setStopBits(StopBits bits)
342	{
343	const auto& rs232 = OUTER(MSXRS232, interface);
344	rs232.getPluggedRS232Dev().setStopBits(bits);
345	}
346
347	void MSXRS232::Interface::setParityBit(bool enable, Parity parity)
348	{
349	const auto& rs232 = OUTER(MSXRS232, interface);
350	rs232.getPluggedRS232Dev().setParityBit(enable, parity);
351	}
352
353	void MSXRS232::Interface::recvByte(uint8_t value, EmuTime time)
354	{
355	const auto& rs232 = OUTER(MSXRS232, interface);
356	rs232.getPluggedRS232Dev().recvByte(value, time);
357	}
358
359	void MSXRS232::Interface::signal(EmuTime time)
360	{
361	const auto& rs232 = OUTER(MSXRS232, interface);
362	rs232.getPluggedRS232Dev().signal(time); // for input
363	}
364
365
366	// Counter 0 output
367
368	void MSXRS232::Counter0::signal(ClockPin& pin, EmuTime time)
369	{
370	auto& rs232 = OUTER(MSXRS232, cntr0);
371	ClockPin& clk = rs232.i8251.getClockPin();
372	if (pin.isPeriodic()) {
373	clk.setPeriodicState(pin.getTotalDuration(),
374	pin.getHighDuration(), time);
375	} else {
376	clk.setState(pin.getState(time), time);
377	}
378	rs232.notifyBaudRate();
379	}
380
381	void MSXRS232::Counter0::signalPosEdge(ClockPin& /pin/, EmuTime /time/)
382	{
383	UNREACHABLE;
384	}
385
386
387	// Counter 1 output // TODO split rx tx
388
389	void MSXRS232::Counter1::signal(ClockPin& pin, EmuTime time)
390	{
391	auto& rs232 = OUTER(MSXRS232, cntr1);
392	ClockPin& clk = rs232.i8251.getClockPin();
393	if (pin.isPeriodic()) {
394	clk.setPeriodicState(pin.getTotalDuration(),
395	pin.getHighDuration(), time);
396	} else {
397	clk.setState(pin.getState(time), time);
398	}
399	rs232.notifyBaudRate();
400	}
401
402	void MSXRS232::Counter1::signalPosEdge(ClockPin& /pin/, EmuTime /time/)
403	{
404	UNREACHABLE;
405	}
406
407
408	// RS232Connector input
409
410	bool MSXRS232::ready()
411	{
412	return i8251.isRecvReady() && !i8251.isRecvFull();
413	}
414
415	bool MSXRS232::acceptsData()
416	{
417	return i8251.isRecvEnabled();
418	}
419
420	void MSXRS232::setDataBits(DataBits bits)
421	{
422	i8251.setDataBits(bits);
423	}
424
425	void MSXRS232::setStopBits(StopBits bits)
426	{
427	i8251.setStopBits(bits);
428	}
429
430	void MSXRS232::setParityBit(bool enable, Parity parity)
431	{
432	i8251.setParityBit(enable, parity);
433	}
434
435	void MSXRS232::recvByte(uint8_t value, EmuTime time)
436	{
437	i8251.recvByte(value, time);
438	}
439
440	// version 1: initial version
441	// version 2: added ioAccessEnabled
442	// TODO: serialize switch status?
443	template<typename Archive>
444	void MSXRS232::serialize(Archive& ar, unsigned version)
445	{
446	ar.template serializeBase<MSXDevice>(*this);
447	ar.template serializeBase<RS232Connector>(*this);
448
449	ar.serialize("I8254", i8254,
450	"I8251", i8251);
451	if (ram) ar.serialize("ram", *ram);
452	ar.serialize("rxrdyIRQ", rxrdyIRQ,
453	"rxrdyIRQlatch", rxrdyIRQlatch,
454	"rxrdyIRQenabled", rxrdyIRQenabled);
455	if (ar.versionAtLeast(version, 2)) {
456	ar.serialize("ioAccessEnabled", ioAccessEnabled);
457	} else {
458	assert(Archive::IS_LOADER);
459	ioAccessEnabled = !hasMemoryBasedIo; // we can't know the
460	// actual value, but this is probably
461	// safest
462	}
463
464	// don't serialize cntr0, cntr1, interface
465	}
466	INSTANTIATE_SERIALIZE_METHODS(MSXRS232);
467	REGISTER_MSXDEVICE(MSXRS232, "RS232");
468
469	} // namespace openmsx

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