/*************************************************************************** Z80 CTC (Z8430) implementation based on original version (c) 1997, Tatsuyuki Satoh Copyright Nicola Salmoria and the MAME Team. Visit http://mamedev.org for licensing and usage restrictions. ***************************************************************************/ #include "emu.h" #include "z80ctc.h" #include "cpu/z80/z80.h" #include "cpu/z80/z80daisy.h" //************************************************************************** // DEBUGGING //************************************************************************** #define VERBOSE 0 #define VPRINTF(x) do { if (VERBOSE) logerror x; } while (0) //************************************************************************** // CONSTANTS //************************************************************************** // these are the bits of the incoming commands to the CTC const int INTERRUPT = 0x80; const int INTERRUPT_ON = 0x80; const int INTERRUPT_OFF = 0x00; const int MODE = 0x40; const int MODE_TIMER = 0x00; const int MODE_COUNTER = 0x40; const int PRESCALER = 0x20; const int PRESCALER_256 = 0x20; const int PRESCALER_16 = 0x00; const int EDGE = 0x10; const int EDGE_FALLING = 0x00; const int EDGE_RISING = 0x10; const int TRIGGER = 0x08; const int TRIGGER_AUTO = 0x00; const int TRIGGER_CLOCK = 0x08; const int CONSTANT = 0x04; const int CONSTANT_LOAD = 0x04; const int CONSTANT_NONE = 0x00; const int RESET = 0x02; const int RESET_CONTINUE = 0x00; const int RESET_ACTIVE = 0x02; const int CONTROL = 0x01; const int CONTROL_VECTOR = 0x00; const int CONTROL_WORD = 0x01; // these extra bits help us keep things accurate const int WAITING_FOR_TRIG = 0x100; //************************************************************************** // LIVE DEVICE //************************************************************************** // device type definition const device_type Z80CTC = &device_creator; //------------------------------------------------- // z80ctc_device - constructor //------------------------------------------------- z80ctc_device::z80ctc_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) : device_t(mconfig, Z80CTC, "Zilog Z80 CTC", tag, owner, clock), device_z80daisy_interface(mconfig, *this) { } //------------------------------------------------- // read - standard handler for reading //------------------------------------------------- READ8_MEMBER( z80ctc_device::read ) { return read(offset & 3); } //------------------------------------------------- // write - standard handler for writing //------------------------------------------------- WRITE8_MEMBER( z80ctc_device::write ) { write(offset & 3, data); } //------------------------------------------------- // trg0-3 - standard write line handlers for each // trigger //------------------------------------------------- WRITE_LINE_MEMBER( z80ctc_device::trg0 ) { trigger(0, state); } WRITE_LINE_MEMBER( z80ctc_device::trg1 ) { trigger(1, state); } WRITE_LINE_MEMBER( z80ctc_device::trg2 ) { trigger(2, state); } WRITE_LINE_MEMBER( z80ctc_device::trg3 ) { trigger(3, state); } //------------------------------------------------- // device_config_complete - perform any // operations now that the configuration is // complete //------------------------------------------------- void z80ctc_device::device_config_complete() { // inherit a copy of the static data const z80ctc_interface *intf = reinterpret_cast(static_config()); if (intf != NULL) *static_cast(this) = *intf; // or initialize to defaults if none provided else { memset(&m_intr_cb, 0, sizeof(m_intr_cb)); memset(&m_zc0_cb, 0, sizeof(m_zc0_cb)); memset(&m_zc1_cb, 0, sizeof(m_zc1_cb)); memset(&m_zc2_cb, 0, sizeof(m_zc2_cb)); } } //------------------------------------------------- // device_start - device-specific startup //------------------------------------------------- void z80ctc_device::device_start() { m_period16 = attotime::from_hz(m_clock) * 16; m_period256 = attotime::from_hz(m_clock) * 256; // resolve callbacks m_intr.resolve(m_intr_cb, *this); // start each channel devcb_write_line nullcb = DEVCB_NULL; m_channel[0].start(this, 0, m_zc0_cb); m_channel[1].start(this, 1, m_zc1_cb); m_channel[2].start(this, 2, m_zc2_cb); m_channel[3].start(this, 3, nullcb); // register for save states save_item(NAME(m_vector)); } //------------------------------------------------- // device_reset - device-specific reset //------------------------------------------------- void z80ctc_device::device_reset() { // reset each channel m_channel[0].reset(); m_channel[1].reset(); m_channel[2].reset(); m_channel[3].reset(); // check for interrupts interrupt_check(); VPRINTF(("CTC Reset\n")); } //************************************************************************** // DAISY CHAIN INTERFACE //************************************************************************** //------------------------------------------------- // z80daisy_irq_state - return the overall IRQ // state for this device //------------------------------------------------- int z80ctc_device::z80daisy_irq_state() { VPRINTF(("CTC IRQ state = %d%d%d%d\n", m_channel[0].m_int_state, m_channel[1].m_int_state, m_channel[2].m_int_state, m_channel[3].m_int_state)); // loop over all channels int state = 0; for (int ch = 0; ch < 4; ch++) { ctc_channel &channel = m_channel[ch]; // if we're servicing a request, don't indicate more interrupts if (channel.m_int_state & Z80_DAISY_IEO) { state |= Z80_DAISY_IEO; break; } state |= channel.m_int_state; } return state; } //------------------------------------------------- // z80daisy_irq_ack - acknowledge an IRQ and // return the appropriate vector //------------------------------------------------- int z80ctc_device::z80daisy_irq_ack() { // loop over all channels for (int ch = 0; ch < 4; ch++) { ctc_channel &channel = m_channel[ch]; // find the first channel with an interrupt requested if (channel.m_int_state & Z80_DAISY_INT) { VPRINTF(("CTC IRQAck ch%d\n", ch)); // clear interrupt, switch to the IEO state, and update the IRQs channel.m_int_state = Z80_DAISY_IEO; interrupt_check(); return m_vector + ch * 2; } } logerror("z80ctc_irq_ack: failed to find an interrupt to ack!\n"); return m_vector; } //------------------------------------------------- // z80daisy_irq_reti - clear the interrupt // pending state to allow other interrupts through //------------------------------------------------- void z80ctc_device::z80daisy_irq_reti() { // loop over all channels for (int ch = 0; ch < 4; ch++) { ctc_channel &channel = m_channel[ch]; // find the first channel with an IEO pending if (channel.m_int_state & Z80_DAISY_IEO) { VPRINTF(("CTC IRQReti ch%d\n", ch)); // clear the IEO state and update the IRQs channel.m_int_state &= ~Z80_DAISY_IEO; interrupt_check(); return; } } logerror("z80ctc_irq_reti: failed to find an interrupt to clear IEO on!\n"); } //************************************************************************** // INTERNAL STATE MANAGEMENT //************************************************************************** //------------------------------------------------- // interrupt_check - look for pending interrupts // and update the line //------------------------------------------------- void z80ctc_device::interrupt_check() { int state = (z80daisy_irq_state() & Z80_DAISY_INT) ? ASSERT_LINE : CLEAR_LINE; m_intr(state); } //************************************************************************* // CTC CHANNELS //************************************************************************** //------------------------------------------------- // ctc_channel - constructor //------------------------------------------------- z80ctc_device::ctc_channel::ctc_channel() : m_mode(0), m_tconst(0), m_down(0), m_extclk(0), m_timer(NULL), m_int_state(0) { memset(&m_zc, 0, sizeof(m_zc)); } //------------------------------------------------- // start - set up at device start time //------------------------------------------------- void z80ctc_device::ctc_channel::start(z80ctc_device *device, int index, const devcb_write_line &write_line) { // initialize state m_device = device; m_index = index; m_zc.resolve(write_line, *m_device); m_timer = m_device->machine().scheduler().timer_alloc(FUNC(static_timer_callback), this); // register for save states m_device->save_item(NAME(m_mode), m_index); m_device->save_item(NAME(m_tconst), m_index); m_device->save_item(NAME(m_down), m_index); m_device->save_item(NAME(m_extclk), m_index); m_device->save_item(NAME(m_int_state), m_index); } //------------------------------------------------- // reset - reset the channel //------------------------------------------------- void z80ctc_device::ctc_channel::reset() { m_mode = RESET_ACTIVE; m_tconst = 0x100; m_timer->adjust(attotime::never); m_int_state = 0; } //------------------------------------------------- // period - return the current channel's period //------------------------------------------------- attotime z80ctc_device::ctc_channel::period() const { // if reset active, no period if ((m_mode & RESET) == RESET_ACTIVE) return attotime::zero; // if counter mode, no real period if ((m_mode & MODE) == MODE_COUNTER) { logerror("CTC %d is CounterMode : Can't calculate period\n", m_index); return attotime::zero; } // compute the period attotime period = ((m_mode & PRESCALER) == PRESCALER_16) ? m_device->m_period16 : m_device->m_period256; return period * m_tconst; } //------------------------------------------------- // read - read the channel's state //------------------------------------------------- UINT8 z80ctc_device::ctc_channel::read() { // if we're in counter mode, just return the count if ((m_mode & MODE) == MODE_COUNTER || (m_mode & WAITING_FOR_TRIG)) return m_down; // else compute the down counter value else { attotime period = ((m_mode & PRESCALER) == PRESCALER_16) ? m_device->m_period16 : m_device->m_period256; VPRINTF(("CTC clock %f\n",ATTOSECONDS_TO_HZ(period.attoseconds))); if (m_timer != NULL) return ((int)(m_timer->remaining().as_double() / period.as_double()) + 1) & 0xff; else return 0; } } //------------------------------------------------- // write - handle writes to a channel //------------------------------------------------- void z80ctc_device::ctc_channel::write(UINT8 data) { // if we're waiting for a time constant, this is it if ((m_mode & CONSTANT) == CONSTANT_LOAD) { VPRINTF(("CTC ch.%d constant = %02x\n", m_index, data)); // set the time constant (0 -> 0x100) m_tconst = data ? data : 0x100; // clear the internal mode -- we're no longer waiting m_mode &= ~CONSTANT; // also clear the reset, since the constant gets it going again m_mode &= ~RESET; // if we're in timer mode.... if ((m_mode & MODE) == MODE_TIMER) { // if we're triggering on the time constant, reset the down counter now if ((m_mode & TRIGGER) == TRIGGER_AUTO) { attotime curperiod = period(); m_timer->adjust(curperiod, m_index, curperiod); } // else set the bit indicating that we're waiting for the appropriate trigger else m_mode |= WAITING_FOR_TRIG; } // also set the down counter in case we're clocking externally m_down = m_tconst; } // if we're writing the interrupt vector, handle it specially #if 0 /* Tatsuyuki Satoh changes */ // The 'Z80family handbook' wrote, // interrupt vector is able to set for even channel (0 or 2) else if ((data & CONTROL) == CONTROL_VECTOR && (m_index & 1) == 0) #else else if ((data & CONTROL) == CONTROL_VECTOR && m_index == 0) #endif { m_device->m_vector = data & 0xf8; logerror("CTC Vector = %02x\n", m_device->m_vector); } // this must be a control word else if ((data & CONTROL) == CONTROL_WORD) { // set the new mode m_mode = data; VPRINTF(("CTC ch.%d mode = %02x\n", m_index, data)); // if we're being reset, clear out any pending timers for this channel if ((data & RESET) == RESET_ACTIVE) { m_timer->adjust(attotime::never); // note that we don't clear the interrupt state here! } } } //------------------------------------------------- // trigger - clock this channel and handle any // side-effects //------------------------------------------------- void z80ctc_device::ctc_channel::trigger(UINT8 data) { // normalize data data = data ? 1 : 0; // see if the trigger value has changed if (data != m_extclk) { m_extclk = data; // see if this is the active edge of the trigger if (((m_mode & EDGE) == EDGE_RISING && data) || ((m_mode & EDGE) == EDGE_FALLING && !data)) { // if we're waiting for a trigger, start the timer if ((m_mode & WAITING_FOR_TRIG) && (m_mode & MODE) == MODE_TIMER) { attotime curperiod = period(); VPRINTF(("CTC period %s\n", curperiod.as_string())); m_timer->adjust(curperiod, m_index, curperiod); } // we're no longer waiting m_mode &= ~WAITING_FOR_TRIG; // if we're clocking externally, decrement the count if ((m_mode & MODE) == MODE_COUNTER) { // if we hit zero, do the same thing as for a timer interrupt if (--m_down == 0) timer_callback(); } } } } //------------------------------------------------- // trigger - clock this channel and handle any // side-effects //------------------------------------------------- void z80ctc_device::ctc_channel::timer_callback() { // down counter has reached zero - see if we should interrupt if ((m_mode & INTERRUPT) == INTERRUPT_ON) { m_int_state |= Z80_DAISY_INT; VPRINTF(("CTC timer ch%d\n", m_index)); m_device->interrupt_check(); } // generate the clock pulse m_zc(1); m_zc(0); // reset the down counter m_down = m_tconst; }