/****************************************************************************** Acorn Electron driver MESS Driver By: Wilbert Pol ******************************************************************************/ #include "emu.h" #include "includes/electron.h" #include "sound/beep.h" #include "imagedev/cassette.h" void electron_state::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr) { switch (id) { case TIMER_TAPE_HANDLER: electron_tape_timer_handler(ptr, param); break; case TIMER_SETUP_BEEP: setup_beep(ptr, param); break; case TIMER_SCANLINE_INTERRUPT: electron_scanline_interrupt(ptr, param); break; default: assert_always(FALSE, "Unknown id in electron_state::device_timer"); } } void electron_state::electron_tape_start() { if (m_ula.tape_running ) { return; } m_ula.tape_steps = 0; m_ula.tape_value = 0x80808080; m_ula.high_tone_set = 0; m_ula.bit_count = 0; m_ula.tape_running = 1; m_tape_timer->adjust(attotime::zero, 0, attotime::from_hz(4800)); } void electron_state::electron_tape_stop() { m_ula.tape_running = 0; m_tape_timer->reset(); } #define TAPE_LOW 0x00; #define TAPE_HIGH 0xFF; TIMER_CALLBACK_MEMBER(electron_state::electron_tape_timer_handler) { if ( m_ula.cassette_motor_mode ) { double tap_val; tap_val = m_cassette->input(); if ( tap_val < -0.5 ) { m_ula.tape_value = ( m_ula.tape_value << 8 ) | TAPE_LOW; m_ula.tape_steps++; } else if ( tap_val > 0.5 ) { m_ula.tape_value = ( m_ula.tape_value << 8 ) | TAPE_HIGH; m_ula.tape_steps++; } else { m_ula.tape_steps = 0; m_ula.bit_count = 0; m_ula.high_tone_set = 0; m_ula.tape_value = 0x80808080; } if ( m_ula.tape_steps > 2 && ( m_ula.tape_value == 0x0000FFFF || m_ula.tape_value == 0x00FF00FF ) ) { m_ula.tape_steps = 0; switch( m_ula.bit_count ) { case 0: /* start bit */ m_ula.start_bit = ( ( m_ula.tape_value == 0x0000FFFF ) ? 0 : 1 ); //logerror( "++ Read start bit: %d\n", m_ula.start_bit ); if ( m_ula.start_bit ) { if ( m_ula.high_tone_set ) { m_ula.bit_count--; } } else { m_ula.high_tone_set = 0; } break; case 1: case 2: case 3: case 4: case 5: case 6: case 7: case 8: //logerror( "++ Read regular bit: %d\n", m_ula.tape_value == 0x0000FFFF ? 0 : 1 ); m_ula.tape_byte = ( m_ula.tape_byte >> 1 ) | ( m_ula.tape_value == 0x0000FFFF ? 0 : 0x80 ); break; case 9: /* stop bit */ m_ula.stop_bit = ( ( m_ula.tape_value == 0x0000FFFF ) ? 0 : 1 ); //logerror( "++ Read stop bit: %d\n", m_ula.stop_bit ); if ( m_ula.start_bit && m_ula.stop_bit && m_ula.tape_byte == 0xFF && ! m_ula.high_tone_set ) { electron_interrupt_handler( INT_SET, INT_HIGH_TONE ); m_ula.high_tone_set = 1; } else if ( ! m_ula.start_bit && m_ula.stop_bit ) { //logerror( "-- Byte read from tape: %02x\n", m_ula.tape_byte ); electron_interrupt_handler( INT_SET, INT_RECEIVE_FULL ); } else { logerror( "Invalid start/stop bit combination detected: %d,%d\n", m_ula.start_bit, m_ula.stop_bit ); } break; } m_ula.bit_count = ( m_ula.bit_count + 1 ) % 10; } } } READ8_MEMBER(electron_state::electron_read_keyboard) { UINT8 data = 0; int i; static const char *const keynames[] = { "LINE0", "LINE1", "LINE2", "LINE3", "LINE4", "LINE5", "LINE6", "LINE7", "LINE8", "LINE9", "LINE10", "LINE11", "LINE12", "LINE13" }; //logerror( "PC=%04x: keyboard read from paged rom area, address: %04x", activecpu_get_pc(), offset ); for( i = 0; i < 14; i++ ) { if( !(offset & 1) ) data |= ioport(keynames[i])->read() & 0x0f; offset = offset >> 1; } //logerror( ", data: %02x\n", data ); return data; } READ8_MEMBER(electron_state::electron_jim_r) { return 0xff; } WRITE8_MEMBER(electron_state::electron_jim_w) { } READ8_MEMBER(electron_state::electron_1mhz_r) { return 0xff; } WRITE8_MEMBER(electron_state::electron_1mhz_w) { } READ8_MEMBER(electron_state::electron_ula_r) { UINT8 data = ((UINT8 *)memregion("user1")->base())[0x43E00 + offset]; switch ( offset & 0x0f ) { case 0x00: /* Interrupt status */ data = m_ula.interrupt_status; m_ula.interrupt_status &= ~0x02; break; case 0x01: /* Unknown */ break; case 0x04: /* Casette data shift register */ electron_interrupt_handler(INT_CLEAR, INT_RECEIVE_FULL ); data = m_ula.tape_byte; break; } logerror( "ULA: read offset %02x: %02x\n", offset, data ); return data; } static const int electron_palette_offset[4] = { 0, 4, 5, 1 }; static const UINT16 electron_screen_base[8] = { 0x3000, 0x3000, 0x3000, 0x4000, 0x5800, 0x5800, 0x6000, 0x5800 }; WRITE8_MEMBER(electron_state::electron_ula_w) { int i = electron_palette_offset[(( offset >> 1 ) & 0x03)]; logerror( "ULA: write offset %02x <- %02x\n", offset & 0x0f, data ); switch( offset & 0x0f ) { case 0x00: /* Interrupt control */ m_ula.interrupt_control = data; break; case 0x01: /* Unknown */ break; case 0x02: /* Screen start address #1 */ m_ula.screen_start = ( m_ula.screen_start & 0x7e00 ) | ( ( data & 0xe0 ) << 1 ); logerror( "screen_start changed to %04x\n", m_ula.screen_start ); break; case 0x03: /* Screen start addres #2 */ m_ula.screen_start = ( m_ula.screen_start & 0x1c0 ) | ( ( data & 0x3f ) << 9 ); logerror( "screen_start changed to %04x\n", m_ula.screen_start ); break; case 0x04: /* Cassette data shift register */ break; case 0x05: /* Interrupt clear and paging */ /* rom page requests are honoured when currently bank 0-7 or 12-15 is switched in, * or when 8-11 is currently switched in only switching to bank 8-15 is allowed. * * Rompages 10 and 11 both select the Basic ROM. * Rompages 8 and 9 both select the keyboard. */ if ( ( ( m_ula.rompage & 0x0C ) != 0x08 ) || ( data & 0x08 ) ) { m_ula.rompage = data & 0x0f; if ( m_ula.rompage == 8 || m_ula.rompage == 9 ) { m_ula.rompage = 8; space.install_read_handler( 0x8000, 0xbfff, read8_delegate(FUNC(electron_state::electron_read_keyboard),this)); } else { space.install_read_bank( 0x8000, 0xbfff, "bank2"); } membank("bank2")->set_entry(m_ula.rompage); } if ( data & 0x10 ) { electron_interrupt_handler( INT_CLEAR, INT_DISPLAY_END ); } if ( data & 0x20 ) { electron_interrupt_handler( INT_CLEAR, INT_RTC ); } if ( data & 0x40 ) { electron_interrupt_handler( INT_CLEAR, INT_HIGH_TONE ); } if ( data & 0x80 ) { } break; case 0x06: /* Counter divider */ if ( m_ula.communication_mode == 0x01) { m_beeper->set_frequency( 1000000 / ( 16 * ( data + 1 ) ) ); } break; case 0x07: /* Misc. */ m_ula.communication_mode = ( data >> 1 ) & 0x03; switch( m_ula.communication_mode ) { case 0x00: /* cassette input */ m_beeper->set_state( 0 ); electron_tape_start(); break; case 0x01: /* sound generation */ m_beeper->set_state( 1 ); electron_tape_stop(); break; case 0x02: /* cassette output */ m_beeper->set_state( 0 ); electron_tape_stop(); break; case 0x03: /* not used */ m_beeper->set_state( 0 ); electron_tape_stop(); break; } m_ula.screen_mode = ( data >> 3 ) & 0x07; m_ula.screen_base = electron_screen_base[ m_ula.screen_mode ]; m_ula.screen_size = 0x8000 - m_ula.screen_base; m_ula.vram = (UINT8 *)space.get_read_ptr(m_ula.screen_base ); logerror( "ULA: screen mode set to %d\n", m_ula.screen_mode ); m_ula.cassette_motor_mode = ( data >> 6 ) & 0x01; m_cassette->change_state(m_ula.cassette_motor_mode ? CASSETTE_MOTOR_ENABLED : CASSETTE_MOTOR_DISABLED, CASSETTE_MOTOR_DISABLED ); m_ula.capslock_mode = ( data >> 7 ) & 0x01; break; case 0x08: case 0x0A: case 0x0C: case 0x0E: // video_update m_ula.current_pal[i+10] = (m_ula.current_pal[i+10] & 0x01) | (((data & 0x80) >> 5) | ((data & 0x08) >> 1)); m_ula.current_pal[i+8] = (m_ula.current_pal[i+8] & 0x01) | (((data & 0x40) >> 4) | ((data & 0x04) >> 1)); m_ula.current_pal[i+2] = (m_ula.current_pal[i+2] & 0x03) | ((data & 0x20) >> 3); m_ula.current_pal[i] = (m_ula.current_pal[i] & 0x03) | ((data & 0x10) >> 2); break; case 0x09: case 0x0B: case 0x0D: case 0x0F: // video_update m_ula.current_pal[i+10] = (m_ula.current_pal[i+10] & 0x06) | ((data & 0x08) >> 3); m_ula.current_pal[i+8] = (m_ula.current_pal[i+8] & 0x06) | ((data & 0x04) >> 2); m_ula.current_pal[i+2] = (m_ula.current_pal[i+2] & 0x04) | (((data & 0x20) >> 4) | ((data & 0x02) >> 1)); m_ula.current_pal[i] = (m_ula.current_pal[i] & 0x04) | (((data & 0x10) >> 3) | ((data & 0x01))); break; } } void electron_state::electron_interrupt_handler(int mode, int interrupt) { if ( mode == INT_SET ) { m_ula.interrupt_status |= interrupt; } else { m_ula.interrupt_status &= ~interrupt; } if ( m_ula.interrupt_status & m_ula.interrupt_control & ~0x83 ) { m_ula.interrupt_status |= 0x01; m_maincpu->set_input_line(0, ASSERT_LINE ); } else { m_ula.interrupt_status &= ~0x01; m_maincpu->set_input_line(0, CLEAR_LINE ); } } /************************************** Machine Initialisation functions ***************************************/ TIMER_CALLBACK_MEMBER(electron_state::setup_beep) { m_beeper->set_state( 0 ); m_beeper->set_frequency( 300 ); } void electron_state::machine_reset() { membank("bank2")->set_entry(0); m_ula.communication_mode = 0x04; m_ula.screen_mode = 0; m_ula.cassette_motor_mode = 0; m_ula.capslock_mode = 0; m_ula.screen_mode = 0; m_ula.screen_start = 0x3000; m_ula.screen_base = 0x3000; m_ula.screen_size = 0x8000 - 0x3000; m_ula.screen_addr = 0; m_ula.tape_running = 0; m_ula.vram = (UINT8 *)m_maincpu->space(AS_PROGRAM).get_read_ptr(m_ula.screen_base); } void electron_state::machine_start() { membank("bank2")->configure_entries(0, 16, memregion("user1")->base(), 0x4000); m_ula.interrupt_status = 0x82; m_ula.interrupt_control = 0x00; timer_set(attotime::zero, TIMER_SETUP_BEEP); m_tape_timer = timer_alloc(TIMER_TAPE_HANDLER); } DEVICE_IMAGE_LOAD_MEMBER( electron_state, electron_cart ) { UINT8 *user1 = memregion("user1")->base() + 0x4000; if (image.software_entry() == NULL) { UINT32 filesize = image.length(); if ( filesize != 16384 ) { image.seterror(IMAGE_ERROR_UNSPECIFIED, "Invalid size. Only size 16384 is supported"); return IMAGE_INIT_FAIL; } if (image.fread( user1 + 12 * 16384, filesize) != filesize) { image.seterror(IMAGE_ERROR_UNSPECIFIED, "Error loading file"); return IMAGE_INIT_FAIL; } return IMAGE_INIT_PASS; } int upsize = image.get_software_region_length("uprom"); int losize = image.get_software_region_length("lorom"); if ( upsize != 16384 && upsize != 0 ) { image.seterror(IMAGE_ERROR_UNSPECIFIED, "Invalid size for uprom"); return IMAGE_INIT_FAIL; } if ( losize != 16384 && losize != 0 ) { image.seterror(IMAGE_ERROR_UNSPECIFIED, "Invalid size for lorom"); return IMAGE_INIT_FAIL; } if ( upsize ) { memcpy( user1 + 12 * 16384, image.get_software_region("uprom"), upsize ); } if ( losize ) { memcpy( user1 + 0 * 16384, image.get_software_region("lorom"), losize ); } return IMAGE_INIT_PASS; }