SC3000PPI.cc

Go to the documentation of this file.

#include "SC3000PPI.hh"
#include "MSXMotherBoard.hh"
#include "Reactor.hh"
#include "CassettePort.hh"
#include "JoystickPort.hh"
#include "XMLElement.hh"
#include "GlobalSettings.hh"
#include "narrow.hh"
#include "serialize.hh"
 
namespace openmsx {
 
// MSXDevice
 
SC3000PPI::SC3000PPI(const DeviceConfig& config)
        : MSXDevice(config)
        , cassettePort(getMotherBoard().getCassettePort())
        , i8255(*this, getCurrentTime(), config.getGlobalSettings().getInvalidPpiModeSetting())
        , keyboard(
                config.getMotherBoard(),
                config.getMotherBoard().getScheduler(),
                config.getMotherBoard().getCommandController(),
                config.getMotherBoard().getReactor().getEventDistributor(),
                config.getMotherBoard().getMSXEventDistributor(),
                config.getMotherBoard().getStateChangeDistributor(),
                Keyboard::Matrix::SEGA, config)
{
        MSXMotherBoard& motherBoard = getMotherBoard();
        auto time = getCurrentTime();
 
        for (unsigned i = 0; i < 2; i++) {
                ports[i] = &motherBoard.getJoystickPort(i);
                // Clear strobe bit, or MSX joysticks will stay silent.
                ports[i]->write(0xFB, time);
        }
 
        reset(time);
}
 
void SC3000PPI::reset(EmuTime::param time)
{
        i8255.reset(time);
}
 
byte SC3000PPI::readIO(word port, EmuTime::param time)
{
        return i8255.read(port & 0x03, time);
}
 
byte SC3000PPI::peekIO(word port, EmuTime::param time) const
{
        return i8255.peek(port & 0x03, time);
}
 
void SC3000PPI::writeIO(word port, byte value, EmuTime::param time)
{
        i8255.write(port & 0x03, value, time);
}
 
 
// I8255Interface
 
byte SC3000PPI::readA(EmuTime::param time)
{
        return peekA(time);
}
byte SC3000PPI::peekA(EmuTime::param time) const
{
        if (selectedRow == 7) {
                // Joystick hardware cannot detect when it's being read, so using the
                // read method for peeking should be safe.
                byte joy1 = ports[0]->read(time) & 0x3F;
                byte joy2 = ports[1]->read(time) & 0x3F;
                return narrow_cast<byte>(joy1 | (joy2 << 6));
        } else {
                return keyboard.getKeys()[selectedRow];
        }
}
void SC3000PPI::writeA(byte /*value*/, EmuTime::param /*time*/)
{
}
 
byte SC3000PPI::readB(EmuTime::param time)
{
        return peekB(time);
}
byte SC3000PPI::peekB(EmuTime::param time) const
{
        // TODO: Are bits 4-7 available regardless of which keyboard row is selected?
        //       That would make sense, but check the schematics.
        if (selectedRow == 7) {
                // Joystick hardware cannot detect when it's being read, so using the
                // read method for peeking should be safe.
                byte joy2 = ports[1]->read(time) & 0x3F;
                return 0xF0 | (joy2 >> 2);
        } else {
                /*
                        Signal  Description
 
                        PB0     Keyboard input
                        PB1     Keyboard input
                        PB2     Keyboard input
                        PB3     Keyboard input
                        PB4     /CONT input from cartridge terminal B-11
                        PB5     FAULT input from printer
                        PB6     BUSY input from printer
                        PB7     Cassette tape input
                */
                auto keys = keyboard.getKeys()[selectedRow + 7];
                return 0xF0 | keys;
        }
}
void SC3000PPI::writeB(byte /*value*/, EmuTime::param /*time*/)
{
}
 
nibble SC3000PPI::readC1(EmuTime::param time)
{
        return peekC1(time);
}
nibble SC3000PPI::peekC1(EmuTime::param /*time*/) const
{
        // TODO: Check.
        return 15;
}
nibble SC3000PPI::readC0(EmuTime::param time)
{
        return peekC0(time);
}
nibble SC3000PPI::peekC0(EmuTime::param /*time*/) const
{
        // TODO: Is this selection readable at all? And if so, what is the value
        //       of bit 3?
        return selectedRow;
}
void SC3000PPI::writeC1(nibble value, EmuTime::param time)
{
        if ((prevBits ^ value) & 1) {
                cassettePort.setMotor((value & 1) == 0, time); // 0=0n, 1=Off
        }
        if ((prevBits ^ value) & 2) {
                cassettePort.cassetteOut((value & 2) != 0, time);
        }
        //if ((prevBits ^ value) & 4) {
        //      cassetteDevice.Mute(); // CASAUD, mute case speaker (1=enable, 0=disable)
        //}
        //if ((prevBits ^ value) & 8) {
        //      click.setClick((value & 8) != 0, time);
        //}
        prevBits = value;
}
void SC3000PPI::writeC0(nibble value, EmuTime::param /*time*/)
{
        selectedRow = value & 7;
        //fprintf(stderr, "SC3000PPI: selected row %d\n", selectedRow);
}
 
template<typename Archive>
void SC3000PPI::serialize(Archive& ar, unsigned /*version*/)
{
        ar.template serializeBase<MSXDevice>(*this);
        ar.serialize("i8255", i8255);
 
        // merge prevBits and selectedRow into one byte
        auto portC = byte((prevBits << 4) | (selectedRow << 0));
        ar.serialize("portC", portC);
        if constexpr (Archive::IS_LOADER) {
                selectedRow = (portC >> 0) & 0xF;
                nibble bits = (portC >> 4) & 0xF;
                writeC1(bits, getCurrentTime());
        }
        ar.serialize("keyboard", keyboard);
}
INSTANTIATE_SERIALIZE_METHODS(SC3000PPI);
REGISTER_MSXDEVICE(SC3000PPI, "SC-3000 PPI");
 
} // namespace openmsx