// license:GPL-2.0+ // copyright-holders:Dirk Best /*************************************************************************** National Semiconductor INS8154 N-Channel 128-by-8 Bit RAM Input/Output (RAM I/O) TODO: Strobed modes ***************************************************************************/ #include "emu.h" #include "ins8154.h" /*************************************************************************** CONSTANTS ***************************************************************************/ #define VERBOSE 1 /* Mode Definition Register */ enum { MDR_BASIC = 0x00, MDR_STROBED_INPUT = 0x20, MDR_STROBED_OUTPUT = 0x60, MDR_STROBED_OUTPUT_3STATE = 0xe0 }; //************************************************************************** // LIVE DEVICE //************************************************************************** // device type definition const device_type INS8154 = &device_creator; //------------------------------------------------- // ins8154_device - constructor //------------------------------------------------- ins8154_device::ins8154_device(const machine_config &mconfig, std::string tag, device_t *owner, UINT32 clock) : device_t(mconfig, INS8154, "INS8154 RAM I/O", tag, owner, clock, "ins8154", __FILE__), m_in_a_cb(*this), m_out_a_cb(*this), m_in_b_cb(*this), m_out_b_cb(*this), m_out_irq_cb(*this), m_in_a(0), m_in_b(0), m_out_a(0), m_out_b(0), m_mdr(0), m_odra(0), m_odrb(0) { } //------------------------------------------------- // device_start - device-specific startup //------------------------------------------------- void ins8154_device::device_start() { /* resolve callbacks */ m_in_a_cb.resolve(); m_out_a_cb.resolve_safe(); m_in_b_cb.resolve(); m_out_b_cb.resolve_safe(); m_out_irq_cb.resolve_safe(); /* register for state saving */ save_item(NAME(m_in_a)); save_item(NAME(m_in_b)); save_item(NAME(m_out_a)); save_item(NAME(m_out_b)); save_item(NAME(m_mdr)); save_item(NAME(m_odra)); save_item(NAME(m_odrb)); } //------------------------------------------------- // device_reset - device-specific reset //------------------------------------------------- void ins8154_device::device_reset() { m_in_a = 0; m_in_b = 0; m_out_a = 0; m_out_b = 0; m_mdr = 0; m_odra = 0; m_odrb = 0; } READ8_MEMBER(ins8154_device::ins8154_r) { UINT8 val = 0xff; if (offset > 0x24) { if (VERBOSE) { logerror("%s: INS8154 '%s' Read from invalid offset %02x!\n", machine().describe_context(), tag().c_str(), offset); } return 0xff; } switch (offset) { case 0x20: if(!m_in_a_cb.isnull()) { val = m_in_a_cb(0); } m_in_a = val; break; case 0x21: if(!m_in_b_cb.isnull()) { val = m_in_b_cb(0); } m_in_b = val; break; default: if (offset < 0x08) { if(!m_in_a_cb.isnull()) { val = (m_in_a_cb(0) << (8 - offset)) & 0x80; } m_in_a = val; } else { if(!m_in_b_cb.isnull()) { val = (m_in_b_cb(0) << (8 - (offset >> 4))) & 0x80; } m_in_b = val; } break; } return val; } WRITE8_MEMBER(ins8154_device::ins8154_porta_w) { m_out_a = data; /* Test if any pins are set as outputs */ if (m_odra) { m_out_a_cb((offs_t)0, (data & m_odra) | (m_odra ^ 0xff)); } } WRITE8_MEMBER(ins8154_device::ins8154_portb_w) { m_out_b = data; /* Test if any pins are set as outputs */ if (m_odrb) { m_out_b_cb((offs_t)0, (data & m_odrb) | (m_odrb ^ 0xff)); } } WRITE8_MEMBER(ins8154_device::ins8154_w) { if (offset > 0x24) { if (VERBOSE) { logerror("%s: INS8154 '%s' Write %02x to invalid offset %02x!\n", machine().describe_context(), tag().c_str(), data, offset); } return; } switch (offset) { case 0x20: ins8154_porta_w(space, 0, data); break; case 0x21: ins8154_portb_w(space, 0, data); break; case 0x22: if (VERBOSE) { logerror("%s: INS8154 '%s' ODRA set to %02x\n", machine().describe_context(), tag().c_str(), data); } m_odra = data; break; case 0x23: if (VERBOSE) { logerror("%s: INS8154 '%s' ODRB set to %02x\n", machine().describe_context(), tag().c_str(), data); } m_odrb = data; break; case 0x24: if (VERBOSE) { logerror("%s: INS8154 '%s' MDR set to %02x\n", machine().describe_context(), tag().c_str(), data); } m_mdr = data; break; default: if (offset & 0x10) { /* Set bit */ if (offset < 0x08) { ins8154_porta_w(space, 0, m_out_a |= offset & 0x07); } else { ins8154_portb_w(space, 0, m_out_b |= (offset >> 4) & 0x07); } } else { /* Clear bit */ if (offset < 0x08) { ins8154_porta_w(space, 0, m_out_a & ~(offset & 0x07)); } else { ins8154_portb_w(space, 0, m_out_b & ~((offset >> 4) & 0x07)); } } break; } }