// license:BSD-3-Clause // copyright-holders:Peter Trauner, Mathis Rosenhauer /********************************************************************** Rockwell 6522 VIA interface and emulation This function emulates the functionality of up to 8 6522 versatile interface adapters. This is based on the M6821 emulation in MAME. To do: T2 pulse counting mode Pulse mode handshake output More shift register **********************************************************************/ /* 1999-Dec-22 PeT vc20 random number generation only partly working (reads (uninitialized) timer 1 and timer 2 counter) timer init, reset, read changed */ #include "emu.h" #include "6522via.h" /*************************************************************************** PARAMETERS ***************************************************************************/ #define TRACE_VIA 0 /*************************************************************************** MACROS ***************************************************************************/ /* Macros for PCR */ #define CA1_LOW_TO_HIGH(c) (c & 0x01) #define CA1_HIGH_TO_LOW(c) (!(c & 0x01)) #define CB1_LOW_TO_HIGH(c) (c & 0x10) #define CB1_HIGH_TO_LOW(c) (!(c & 0x10)) #define CA2_INPUT(c) (!(c & 0x08)) #define CA2_LOW_TO_HIGH(c) ((c & 0x0c) == 0x04) #define CA2_HIGH_TO_LOW(c) ((c & 0x0c) == 0x00) #define CA2_IND_IRQ(c) ((c & 0x0a) == 0x02) #define CA2_OUTPUT(c) (c & 0x08) #define CA2_AUTO_HS(c) ((c & 0x0c) == 0x08) #define CA2_HS_OUTPUT(c) ((c & 0x0e) == 0x08) #define CA2_PULSE_OUTPUT(c) ((c & 0x0e) == 0x0a) #define CA2_FIX_OUTPUT(c) ((c & 0x0c) == 0x0c) #define CA2_OUTPUT_LEVEL(c) ((c & 0x02) >> 1) #define CB2_INPUT(c) (!(c & 0x80)) #define CB2_LOW_TO_HIGH(c) ((c & 0xc0) == 0x40) #define CB2_HIGH_TO_LOW(c) ((c & 0xc0) == 0x00) #define CB2_IND_IRQ(c) ((c & 0xa0) == 0x20) #define CB2_OUTPUT(c) (c & 0x80) #define CB2_AUTO_HS(c) ((c & 0xc0) == 0x80) #define CB2_HS_OUTPUT(c) ((c & 0xe0) == 0x80) #define CB2_PULSE_OUTPUT(c) ((c & 0xe0) == 0xa0) #define CB2_FIX_OUTPUT(c) ((c & 0xc0) == 0xc0) #define CB2_OUTPUT_LEVEL(c) ((c & 0x20) >> 5) /* Macros for ACR */ #define PA_LATCH_ENABLE(c) (c & 0x01) #define PB_LATCH_ENABLE(c) (c & 0x02) #define SR_DISABLED(c) (!(c & 0x1c)) #define SI_T2_CONTROL(c) ((c & 0x1c) == 0x04) #define SI_O2_CONTROL(c) ((c & 0x1c) == 0x08) #define SI_EXT_CONTROL(c) ((c & 0x1c) == 0x0c) #define SO_T2_RATE(c) ((c & 0x1c) == 0x10) #define SO_T2_CONTROL(c) ((c & 0x1c) == 0x14) #define SO_O2_CONTROL(c) ((c & 0x1c) == 0x18) #define SO_EXT_CONTROL(c) ((c & 0x1c) == 0x1c) #define T1_SET_PB7(c) (c & 0x80) #define T1_CONTINUOUS(c) (c & 0x40) #define T2_COUNT_PB6(c) (c & 0x20) /* Interrupt flags */ #define INT_CA2 0x01 #define INT_CA1 0x02 #define INT_SR 0x04 #define INT_CB2 0x08 #define INT_CB1 0x10 #define INT_T2 0x20 #define INT_T1 0x40 #define INT_ANY 0x80 #define CLR_PA_INT() clear_int(INT_CA1 | ((!CA2_IND_IRQ(m_pcr)) ? INT_CA2: 0)) #define CLR_PB_INT() clear_int(INT_CB1 | ((!CB2_IND_IRQ(m_pcr)) ? INT_CB2: 0)) #define IFR_DELAY 3 #define TIMER1_VALUE (m_t1ll+(m_t1lh<<8)) #define TIMER2_VALUE (m_t2ll+(m_t2lh<<8)) /*************************************************************************** INLINE FUNCTIONS ***************************************************************************/ UINT16 via6522_device::get_counter1_value() { UINT16 val; if(m_t1_active) { val = attotime_to_clocks(m_t1->remaining()) - IFR_DELAY; } else { val = 0xffff - attotime_to_clocks(machine().time() - m_time1); } return val; } //************************************************************************** // LIVE DEVICE //************************************************************************** // device type definition const device_type VIA6522 = &device_creator; DEVICE_ADDRESS_MAP_START( map, 8, via6522_device ) AM_RANGE(0x00, 0x0f) AM_READWRITE(read, write) ADDRESS_MAP_END //------------------------------------------------- // via6522_device - constructor //------------------------------------------------- via6522_device::via6522_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) : device_t(mconfig, VIA6522, "6522 VIA", tag, owner, clock, "via6522", __FILE__), m_in_a_handler(*this), m_in_b_handler(*this), m_out_a_handler(*this), m_out_b_handler(*this), m_ca2_handler(*this), m_cb1_handler(*this), m_cb2_handler(*this), m_irq_handler(*this), m_in_a(0xff), m_in_ca1(0), m_in_ca2(0), m_out_ca2(0), m_in_b(0), m_in_cb1(0), m_in_cb2(0), m_pcr(0), m_acr(0), m_ier(0), m_ifr(0) { } //------------------------------------------------- // device_start - device-specific startup //------------------------------------------------- void via6522_device::device_start() { m_in_a_handler.resolve(); m_in_b_handler.resolve(); m_out_a_handler.resolve_safe(); m_out_b_handler.resolve_safe(); m_cb1_handler.resolve_safe(); m_ca2_handler.resolve_safe(); m_cb2_handler.resolve_safe(); m_irq_handler.resolve_safe(); m_t1ll = 0xf3; /* via at 0x9110 in vic20 show these values */ m_t1lh = 0xb5; /* ports are not written by kernel! */ m_t2ll = 0xff; /* taken from vice */ m_t2lh = 0xff; m_sr = 0; m_time2 = m_time1 = machine().time(); m_t1 = timer_alloc(TIMER_T1); m_t2 = timer_alloc(TIMER_T2); m_ca2_timer = timer_alloc(TIMER_CA2); m_shift_timer = timer_alloc(TIMER_SHIFT); /* Default clock is from CPU1 */ if (clock() == 0) { set_unscaled_clock(machine().firstcpu->clock()); } /* save state register */ save_item(NAME(m_in_a)); save_item(NAME(m_in_ca1)); save_item(NAME(m_in_ca2)); save_item(NAME(m_out_a)); save_item(NAME(m_out_ca2)); save_item(NAME(m_ddr_a)); save_item(NAME(m_latch_a)); save_item(NAME(m_in_b)); save_item(NAME(m_in_cb1)); save_item(NAME(m_in_cb2)); save_item(NAME(m_out_b)); save_item(NAME(m_out_cb1)); save_item(NAME(m_out_cb2)); save_item(NAME(m_ddr_b)); save_item(NAME(m_latch_b)); save_item(NAME(m_t1cl)); save_item(NAME(m_t1ch)); save_item(NAME(m_t1ll)); save_item(NAME(m_t1lh)); save_item(NAME(m_t2cl)); save_item(NAME(m_t2ch)); save_item(NAME(m_t2ll)); save_item(NAME(m_t2lh)); save_item(NAME(m_sr)); save_item(NAME(m_pcr)); save_item(NAME(m_acr)); save_item(NAME(m_ier)); save_item(NAME(m_ifr)); save_item(NAME(m_time1)); save_item(NAME(m_t1_active)); save_item(NAME(m_t1_pb7)); save_item(NAME(m_time2)); save_item(NAME(m_t2_active)); save_item(NAME(m_shift_counter)); } //------------------------------------------------- // device_reset - device-specific reset //------------------------------------------------- void via6522_device::device_reset() { m_out_a = 0; m_out_ca2 = 1; m_ddr_a = 0; m_latch_a = 0; m_out_b = 0; m_out_cb1 = 1; m_out_cb2 = 1; m_ddr_b = 0; m_latch_b = 0; m_t1cl = 0; m_t1ch = 0; m_t2cl = 0; m_t2ch = 0; m_pcr = 0; m_acr = 0; m_ier = 0; m_ifr = 0; m_t1_active = 0; m_t1_pb7 = 1; m_t2_active = 0; m_shift_counter = 0; output_pa(); output_pb(); m_ca2_handler(m_out_ca2); m_cb1_handler(m_out_cb1); m_cb2_handler(m_out_cb2); } void via6522_device::output_irq() { if (m_ier & m_ifr & 0x7f) { if ((m_ifr & INT_ANY) == 0) { m_ifr |= INT_ANY; m_irq_handler(ASSERT_LINE); } } else { if (m_ifr & INT_ANY) { m_ifr &= ~INT_ANY; m_irq_handler(CLEAR_LINE); } } } /*------------------------------------------------- via_set_int - external interrupt check -------------------------------------------------*/ void via6522_device::set_int(int data) { if (!(m_ifr & data)) { m_ifr |= data; output_irq(); if (TRACE_VIA) { logerror("%s:6522VIA chip %s: IFR = %02X\n", machine().describe_context(), tag(), m_ifr); } } } /*------------------------------------------------- via_clear_int - external interrupt check -------------------------------------------------*/ void via6522_device::clear_int(int data) { if (m_ifr & data) { m_ifr &= ~data; output_irq(); if (TRACE_VIA) { logerror("%s:6522VIA chip %s: IFR = %02X\n", machine().describe_context(), tag(), m_ifr); } } } /*------------------------------------------------- via_shift -------------------------------------------------*/ void via6522_device::shift_out() { m_out_cb2 = (m_sr >> 7) & 1; m_sr = (m_sr << 1) | m_out_cb2; m_cb2_handler(m_out_cb2); if (!SO_T2_RATE(m_acr)) { m_shift_counter = (m_shift_counter + 1) % 8; if (m_shift_counter == 0) { set_int(INT_SR); } } } void via6522_device::shift_in() { m_sr = (m_sr << 1) | (m_in_cb2 & 1); m_shift_counter = (m_shift_counter + 1) % 8; if (m_shift_counter == 0) { set_int(INT_SR); } } void via6522_device::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr) { switch (id) { case TIMER_SHIFT: m_out_cb1 = 0; m_cb1_handler(m_out_cb1); if (SO_T2_RATE(m_acr) || SO_T2_CONTROL(m_acr) || SO_O2_CONTROL(m_acr)) { shift_out(); } m_out_cb1 = 1; m_cb1_handler(m_out_cb1); if (SI_T2_CONTROL(m_acr) || SI_O2_CONTROL(m_acr)) { shift_in(); } if (SO_T2_RATE(m_acr) || m_shift_counter) { if (SI_O2_CONTROL(m_acr) || SO_O2_CONTROL(m_acr)) { m_shift_timer->adjust(clocks_to_attotime(2)); } else { m_shift_timer->adjust(clocks_to_attotime((m_t2ll + 2)*2)); } } break; case TIMER_T1: if (T1_CONTINUOUS (m_acr)) { m_t1_pb7 = !m_t1_pb7; m_t1->adjust(clocks_to_attotime(TIMER1_VALUE + IFR_DELAY)); } else { m_t1_pb7 = 1; m_t1_active = 0; m_time1 = machine().time(); } if (T1_SET_PB7(m_acr)) { output_pb(); } set_int(INT_T1); break; case TIMER_T2: m_t2_active = 0; m_time2 = machine().time(); set_int(INT_T2); break; case TIMER_CA2: m_out_ca2 = 1; m_ca2_handler(m_out_ca2); break; } } UINT8 via6522_device::input_pa() { /// TODO: REMOVE THIS if (!m_in_a_handler.isnull()) { if (m_ddr_a != 0xff) m_in_a = m_in_a_handler(0); return (m_out_a & m_ddr_a) + (m_in_a & ~m_ddr_a); } return m_in_a & (m_out_a | ~m_ddr_a); } void via6522_device::output_pa() { UINT8 pa = (m_out_a & m_ddr_a) | ~m_ddr_a; m_out_a_handler(pa); } UINT8 via6522_device::input_pb() { /// TODO: REMOVE THIS if (m_ddr_b != 0xff && !m_in_b_handler.isnull()) { m_in_b = m_in_b_handler(0); } UINT8 pb = (m_out_b & m_ddr_b) + (m_in_b & ~m_ddr_b); if (T1_SET_PB7(m_acr)) pb = (pb & 0x7f) | (m_t1_pb7 << 7); return pb; } void via6522_device::output_pb() { UINT8 pb = (m_out_b & m_ddr_b) | ~m_ddr_b; if (T1_SET_PB7(m_acr)) pb = (pb & 0x7f) | (m_t1_pb7 << 7); m_out_b_handler(pb); } /*------------------------------------------------- via_r - CPU interface for VIA read -------------------------------------------------*/ READ8_MEMBER( via6522_device::read ) { int val = 0; if (space.debugger_access()) return 0; offset &= 0xf; switch (offset) { case VIA_PB: /* update the input */ if (PB_LATCH_ENABLE(m_acr) == 0) { val = input_pb(); } else { val = m_latch_b; } CLR_PB_INT(); break; case VIA_PA: /* update the input */ if (PA_LATCH_ENABLE(m_acr) == 0) { val = input_pa(); } else { val = m_latch_a; } CLR_PA_INT(); if (m_out_ca2 && (CA2_PULSE_OUTPUT(m_pcr) || CA2_AUTO_HS(m_pcr))) { m_out_ca2 = 0; m_ca2_handler(m_out_ca2); } if (CA2_PULSE_OUTPUT(m_pcr)) m_ca2_timer->adjust(clocks_to_attotime(1)); break; case VIA_PANH: /* update the input */ if (PA_LATCH_ENABLE(m_acr) == 0) { val = input_pa(); } else { val = m_latch_a; } break; case VIA_DDRB: val = m_ddr_b; break; case VIA_DDRA: val = m_ddr_a; break; case VIA_T1CL: clear_int(INT_T1); val = get_counter1_value() & 0xFF; break; case VIA_T1CH: val = get_counter1_value() >> 8; break; case VIA_T1LL: val = m_t1ll; break; case VIA_T1LH: val = m_t1lh; break; case VIA_T2CL: clear_int(INT_T2); if (m_t2_active) { val = attotime_to_clocks(m_t2->remaining()) & 0xff; } else { if (T2_COUNT_PB6(m_acr)) { val = m_t2cl; } else { val = (0x10000 - (attotime_to_clocks(machine().time() - m_time2) & 0xffff) - 1) & 0xff; } } break; case VIA_T2CH: if (m_t2_active) { val = attotime_to_clocks(m_t2->remaining()) >> 8; } else { if (T2_COUNT_PB6(m_acr)) { val = m_t2ch; } else { val = (0x10000 - (attotime_to_clocks(machine().time() - m_time2) & 0xffff) - 1) >> 8; } } break; case VIA_SR: val = m_sr; m_shift_counter=0; clear_int(INT_SR); if (SI_O2_CONTROL(m_acr)) { m_shift_timer->adjust(clocks_to_attotime(2)); } if (SI_T2_CONTROL(m_acr)) { m_shift_timer->adjust(clocks_to_attotime((m_t2ll + 2)*2)); } break; case VIA_PCR: val = m_pcr; break; case VIA_ACR: val = m_acr; break; case VIA_IER: val = m_ier | 0x80; break; case VIA_IFR: val = m_ifr; break; } return val; } /*------------------------------------------------- via_w - CPU interface for VIA write -------------------------------------------------*/ WRITE8_MEMBER( via6522_device::write ) { offset &=0x0f; switch (offset) { case VIA_PB: m_out_b = data; if (m_ddr_b != 0) { output_pb(); } CLR_PB_INT(); if (m_out_cb2 && CB2_AUTO_HS(m_pcr)) { m_out_cb2 = 0; m_cb2_handler(m_out_cb2); } break; case VIA_PA: m_out_a = data; if (m_ddr_a != 0) { output_pa(); } CLR_PA_INT(); if (m_out_ca2 && (CA2_PULSE_OUTPUT(m_pcr) || CA2_AUTO_HS(m_pcr))) { m_out_ca2 = 0; m_ca2_handler(m_out_ca2); } if (CA2_PULSE_OUTPUT(m_pcr)) m_ca2_timer->adjust(clocks_to_attotime(1)); break; case VIA_PANH: m_out_a = data; if (m_ddr_a != 0) { output_pa(); } break; case VIA_DDRB: if ( data != m_ddr_b ) { m_ddr_b = data; output_pb(); } break; case VIA_DDRA: if (m_ddr_a != data) { m_ddr_a = data; output_pa(); } break; case VIA_T1CL: case VIA_T1LL: m_t1ll = data; break; case VIA_T1LH: m_t1lh = data; clear_int(INT_T1); break; case VIA_T1CH: m_t1ch = m_t1lh = data; m_t1cl = m_t1ll; clear_int(INT_T1); m_t1_pb7 = 0; if (T1_SET_PB7(m_acr)) { output_pb(); } m_t1->adjust(clocks_to_attotime(TIMER1_VALUE + IFR_DELAY)); m_t1_active = 1; break; case VIA_T2CL: m_t2ll = data; break; case VIA_T2CH: m_t2ch = m_t2lh = data; m_t2cl = m_t2ll; clear_int(INT_T2); if (!T2_COUNT_PB6(m_acr)) { m_t2->adjust(clocks_to_attotime(TIMER2_VALUE + IFR_DELAY)); m_t2_active = 1; } else { m_t2->adjust(clocks_to_attotime(TIMER2_VALUE)); m_t2_active = 1; m_time2 = machine().time(); } break; case VIA_SR: m_sr = data; m_shift_counter=0; clear_int(INT_SR); if (SO_O2_CONTROL(m_acr)) { m_shift_timer->adjust(clocks_to_attotime(2)); } if (SO_T2_RATE(m_acr) || SO_T2_CONTROL(m_acr)) { m_shift_timer->adjust(clocks_to_attotime((m_t2ll + 2)*2)); } break; case VIA_PCR: m_pcr = data; if (TRACE_VIA) { logerror("%s:6522VIA chip %s: PCR = %02X\n", machine().describe_context(), tag(), data); } if (CA2_FIX_OUTPUT(data) && m_out_ca2 != CA2_OUTPUT_LEVEL(data)) { m_out_ca2 = CA2_OUTPUT_LEVEL(data); m_ca2_handler(m_out_ca2); } if (CB2_FIX_OUTPUT(data) && m_out_cb2 != CB2_OUTPUT_LEVEL(data)) { m_out_cb2 = CB2_OUTPUT_LEVEL(data); m_cb2_handler(m_out_cb2); } break; case VIA_ACR: { UINT16 counter1 = get_counter1_value(); m_acr = data; output_pb(); if (T1_CONTINUOUS(data)) { m_t1->adjust(clocks_to_attotime(counter1 + IFR_DELAY)); m_t1_active = 1; } } break; case VIA_IER: if (data & 0x80) { m_ier |= data & 0x7f; } else { m_ier &= ~(data & 0x7f); } output_irq(); break; case VIA_IFR: if (data & INT_ANY) { data = 0x7f; } clear_int(data); break; } } void via6522_device::write_pa(int line, int state) { if (state) m_in_a |= (1 << line); else m_in_a &= ~(1 << line); } WRITE8_MEMBER( via6522_device::write_pa ) { m_in_a = data; } /*------------------------------------------------- ca1_w - interface setting VIA port CA1 input -------------------------------------------------*/ WRITE_LINE_MEMBER( via6522_device::write_ca1 ) { if (m_in_ca1 != state) { m_in_ca1 = state; if (TRACE_VIA) logerror("%s:6522VIA chip %s: CA1 = %02X\n", machine().describe_context(), tag(), m_in_ca1); if ((m_in_ca1 && CA1_LOW_TO_HIGH(m_pcr)) || (!m_in_ca1 && CA1_HIGH_TO_LOW(m_pcr))) { if (PA_LATCH_ENABLE(m_acr)) { m_latch_a = input_pa(); } set_int(INT_CA1); if (!m_out_ca2 && CA2_AUTO_HS(m_pcr)) { m_out_ca2 = 1; m_ca2_handler(m_out_ca2); } } } } /*------------------------------------------------- ca2_w - interface setting VIA port CA2 input -------------------------------------------------*/ WRITE_LINE_MEMBER( via6522_device::write_ca2 ) { if (m_in_ca2 != state) { m_in_ca2 = state; if (CA2_INPUT(m_pcr)) { if ((m_in_ca2 && CA2_LOW_TO_HIGH(m_pcr)) || (!m_in_ca2 && CA2_HIGH_TO_LOW(m_pcr))) { set_int(INT_CA2); } } } } void via6522_device::write_pb(int line, int state) { if (state) m_in_b |= (1 << line); else m_in_b &= ~(1 << line); } WRITE8_MEMBER( via6522_device::write_pb ) { m_in_b = data; } /*------------------------------------------------- cb1_w - interface setting VIA port CB1 input -------------------------------------------------*/ WRITE_LINE_MEMBER( via6522_device::write_cb1 ) { if (m_in_cb1 != state) { m_in_cb1 = state; if ((m_in_cb1 && CB1_LOW_TO_HIGH(m_pcr)) || (!m_in_cb1 && CB1_HIGH_TO_LOW(m_pcr))) { if (PB_LATCH_ENABLE(m_acr)) { m_latch_b = input_pb(); } if (SO_EXT_CONTROL(m_acr)) { shift_out(); } if (SI_EXT_CONTROL(m_acr)) { shift_in(); } set_int(INT_CB1); if (!m_out_cb2 && CB2_AUTO_HS(m_pcr)) { m_out_cb2 = 1; m_cb2_handler(1); } } } } /*------------------------------------------------- cb2_w - interface setting VIA port CB2 input -------------------------------------------------*/ WRITE_LINE_MEMBER( via6522_device::write_cb2 ) { if (m_in_cb2 != state) { m_in_cb2 = state; if (CB2_INPUT(m_pcr)) { if ((m_in_cb2 && CB2_LOW_TO_HIGH(m_pcr)) || (!m_in_cb2 && CB2_HIGH_TO_LOW(m_pcr))) { set_int(INT_CB2); } } } }