mirror of
https://github.com/holub/mame
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722631601e
for identifying targets and simplified the code. [Aaron Giles] I have some further ideas but this is a good midway point.
371 lines
8.1 KiB
C
371 lines
8.1 KiB
C
/**********************************************************************
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Motorola MC6852 Synchronous Serial Data Adapter emulation
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Copyright MESS Team.
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Visit http://mamedev.org for licensing and usage restrictions.
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**********************************************************************/
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/*
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TODO:
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- FIFO
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- receive
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- transmit
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- parity
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- 1-sync-character mode
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- 2-sync-character mode
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- external sync mode
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- interrupts
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*/
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#include "emu.h"
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#include "mc6852.h"
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#include "machine/devhelpr.h"
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// device type definition
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const device_type MC6852 = &device_creator<mc6852_device>;
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//**************************************************************************
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// MACROS / CONSTANTS
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//**************************************************************************
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#define LOG 0
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#define S_RDA 0x01
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#define S_TDRA 0x02
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#define S_DCD 0x04
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#define S_CTS 0x08
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#define S_TUF 0x10
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#define S_RX_OVRN 0x20
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#define S_PE 0x40
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#define S_IRQ 0x80
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#define C1_RX_RS 0x01
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#define C1_TX_RS 0x02
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#define C1_STRIP_SYNC 0x04
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#define C1_CLEAR_SYNC 0x08
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#define C1_TIE 0x10
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#define C1_RIE 0x20
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#define C1_AC_MASK 0xc0
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#define C1_AC_C2 0x00
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#define C1_AC_C3 0x40
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#define C1_AC_SYNC 0x80
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#define C1_AC_TX_FIFO 0xc0
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#define C2_PC1 0x01
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#define C2_PC2 0x02
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#define C2_1_2_BYTE 0x04
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#define C2_WS_MASK 0x38
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#define C2_WS_6_E 0x00
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#define C2_WS_6_O 0x08
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#define C2_WS_7 0x10
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#define C2_WS_8 0x18
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#define C2_WS_7_E 0x20
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#define C2_WS_7_O 0x28
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#define C2_WS_8_E 0x30
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#define C2_WS_8_O 0x38
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#define C2_TX_SYNC 0x40
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#define C2_EIE 0x80
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#define C3_E_I_SYNC 0x01
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#define C3_1_2_SYNC 0x02
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#define C3_CLEAR_CTS 0x04
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#define C3_CTUF 0x08
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//**************************************************************************
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// INLINE HELPERS
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//**************************************************************************
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inline void mc6852_device::receive()
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{
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}
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inline void mc6852_device::transmit()
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{
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}
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//**************************************************************************
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// LIVE DEVICE
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//**************************************************************************
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//-------------------------------------------------
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// mc6852_device - constructor
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//-------------------------------------------------
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mc6852_device::mc6852_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock)
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: device_t(mconfig, MC6852, "MC6852", tag, owner, clock)
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{
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}
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//-------------------------------------------------
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// device_config_complete - perform any
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// operations now that the configuration is
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// complete
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//-------------------------------------------------
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void mc6852_device::device_config_complete()
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{
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// inherit a copy of the static data
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const mc6852_interface *intf = reinterpret_cast<const mc6852_interface *>(static_config());
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if (intf != NULL)
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*static_cast<mc6852_interface *>(this) = *intf;
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// or initialize to defaults if none provided
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else
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{
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memset(&m_in_rx_data_cb, 0, sizeof(m_in_rx_data_cb));
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memset(&m_out_tx_data_cb, 0, sizeof(m_out_tx_data_cb));
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memset(&m_out_irq_cb, 0, sizeof(m_out_irq_cb));
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memset(&m_in_cts_cb, 0, sizeof(m_in_cts_cb));
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memset(&m_in_dcd_cb, 0, sizeof(m_in_dcd_cb));
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memset(&m_out_sm_dtr_cb, 0, sizeof(m_out_sm_dtr_cb));
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memset(&m_out_tuf_cb, 0, sizeof(m_out_tuf_cb));
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}
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}
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//-------------------------------------------------
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// device_start - device-specific startup
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//-------------------------------------------------
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void mc6852_device::device_start()
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{
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// resolve callbacks
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m_in_rx_data_func.resolve(m_in_rx_data_cb, *this);
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m_out_tx_data_func.resolve(m_out_tx_data_cb, *this);
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m_out_irq_func.resolve(m_out_irq_cb, *this);
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m_in_cts_func.resolve(m_in_cts_cb, *this);
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m_in_dcd_func.resolve(m_in_dcd_cb, *this);
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m_out_sm_dtr_func.resolve(m_out_sm_dtr_cb, *this);
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m_out_tuf_func.resolve(m_out_tuf_cb, *this);
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if (m_rx_clock > 0)
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{
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m_rx_timer = timer_alloc(TIMER_RX);
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m_rx_timer->adjust(attotime::zero, 0, attotime::from_hz(m_rx_clock));
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}
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if (m_tx_clock > 0)
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{
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m_tx_timer = timer_alloc(TIMER_TX);
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m_tx_timer->adjust(attotime::zero, 0, attotime::from_hz(m_tx_clock));
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}
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// register for state saving
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save_item(NAME(m_status));
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save_item(NAME(m_cr));
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save_item(NAME(m_scr));
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save_item(NAME(m_rx_fifo));
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save_item(NAME(m_tx_fifo));
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save_item(NAME(m_tdr));
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save_item(NAME(m_tsr));
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save_item(NAME(m_rdr));
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save_item(NAME(m_rsr));
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save_item(NAME(m_cts));
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save_item(NAME(m_dcd));
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save_item(NAME(m_sm_dtr));
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save_item(NAME(m_tuf));
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}
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//-------------------------------------------------
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// device_reset - device-specific reset
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//-------------------------------------------------
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void mc6852_device::device_reset()
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{
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/* set receiver shift register to all 1's */
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m_rsr = 0xff;
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/* reset and inhibit receiver/transmitter sections */
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m_cr[0] |= (C1_TX_RS | C1_RX_RS);
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}
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//-------------------------------------------------
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// device_timer - handler timer events
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//-------------------------------------------------
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void mc6852_device::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr)
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{
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switch (id)
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{
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case TIMER_RX:
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receive();
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break;
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case TIMER_TX:
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transmit();
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break;
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}
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}
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//-------------------------------------------------
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// read -
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//-------------------------------------------------
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READ8_MEMBER( mc6852_device::read )
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{
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UINT8 data = 0;
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if (BIT(offset, 0))
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{
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/* receive data FIFO */
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}
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else
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{
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/* status */
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data = m_status;
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}
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return data;
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}
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//-------------------------------------------------
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// write -
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//-------------------------------------------------
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WRITE8_MEMBER( mc6852_device::write )
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{
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if (BIT(offset, 0))
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{
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switch (m_cr[0] & C1_AC_MASK)
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{
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case C1_AC_C2:
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/* control 2 */
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m_cr[1] = data;
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break;
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case C1_AC_C3:
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/* control 3 */
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m_cr[2] = data;
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break;
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case C1_AC_SYNC:
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/* sync code */
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m_scr = data;
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break;
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case C1_AC_TX_FIFO:
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/* transmit data FIFO */
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break;
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}
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}
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else
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{
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/* receiver reset */
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if (data & C1_RX_RS)
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{
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/* When Rx Rs is set, it clears the receiver
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control logic, sync logic, error logic, Rx Data FIFO Control,
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Parity Error status bit, and DCD interrupt. The Receiver Shift
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Register is set to ones.
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*/
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if (LOG) logerror("MC6852 '%s' Receiver Reset\n", tag());
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m_status &= ~(S_RX_OVRN | S_PE | S_DCD | S_RDA);
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m_rsr = 0xff;
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}
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/* transmitter reset */
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if (data & C1_TX_RS)
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{
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/* When Tx Rs is set, it clears the transmitter
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control section, Transmitter Shift Register, Tx Data FIFO
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Control (the Tx Data FIFO can be reloaded after one E clock
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pulse), the Transmitter Underflow status bit, and the CTS interrupt,
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and inhibits the TDRA status bit (in the one-sync-character
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and two-sync-character modes).*/
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if (LOG) logerror("MC6852 '%s' Transmitter Reset\n", tag());
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m_status &= ~(S_TUF | S_CTS | S_TDRA);
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}
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if (LOG)
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{
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if (data & C1_STRIP_SYNC) logerror("MC6852 '%s' Strip Synchronization Characters\n", tag());
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if (data & C1_CLEAR_SYNC) logerror("MC6852 '%s' Clear Synchronization\n", tag());
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}
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m_cr[0] = data;
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}
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}
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//-------------------------------------------------
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// rx_clk_w -
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//-------------------------------------------------
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WRITE_LINE_MEMBER( mc6852_device::rx_clk_w )
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{
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if (state) receive();
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}
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//-------------------------------------------------
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// tx_clk_w -
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//-------------------------------------------------
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WRITE_LINE_MEMBER( mc6852_device::tx_clk_w )
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{
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if (state) transmit();
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}
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//-------------------------------------------------
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// cts_w -
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//-------------------------------------------------
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WRITE_LINE_MEMBER( mc6852_device::cts_w )
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{
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m_cts = state;
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}
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//-------------------------------------------------
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// dcd_w -
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//-------------------------------------------------
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WRITE_LINE_MEMBER( mc6852_device::dcd_w )
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{
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m_dcd = state;
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}
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//-------------------------------------------------
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// sm_dtr_r -
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//-------------------------------------------------
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READ_LINE_MEMBER( mc6852_device::sm_dtr_r )
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{
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return m_sm_dtr;
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}
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//-------------------------------------------------
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// tuf_r -
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//-------------------------------------------------
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READ_LINE_MEMBER( mc6852_device::tuf_r )
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{
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return m_tuf;
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}
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