mirror of
https://github.com/holub/mame
synced 2025-10-04 16:34:53 +03:00
e133bf83cc
Split out the PIA IDE hard disk interface from the swtpc09 machine. This support appears to have been incomplete or to have bit rotten, and has been updated and tested lightly with FLEX9.
231 lines
7.8 KiB
C++
231 lines
7.8 KiB
C++
// license:BSD-3-Clause
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// copyright-holders:AJR
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/**********************************************************************
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SWTPC SS-50 I/O port interface
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The SS-50 bus is actually two buses in one: a 50-pin master bus
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used by RAM boards and such, and a 30-pin I/O bus derived from it
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either on the motherboard or a dedicated interface board, which
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provides each of eight "interface" cards with its specific chip
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select line and only a few address lines for register selection.
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This 30-pin bus is what is emulated here.
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As originally introduced in the 6800 Computer System, the
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interface bus only included two register select lines, just enough
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to drive one MC6820 PIA. No defined signals were placed on the
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first two lines, which cards were permitted to use for any
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purpose. The original MP-B motherboard also quite wastefully
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reserved 8K (technically 4K) of address space to map a maximum of
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32 read/write registers. The later MC6809-oriented systems not
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only reduced the I/O segment to a selectable 1K, but appropriated
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the two formerly undefined lines for two additional register
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select lines, making it possible to use more complex interface
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cards but breaking compatibility with some earlier ones.
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An unusual feature of the SS-50 bus is the presence of five baud
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rate frequencies, selected from among the (inverted) outputs of
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a MC14411 Bit Rate Generator. The 6800 Computer System provided
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only rates between 110 and 1200 (multiplied by 16), and also used
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the MC14411's master frequency to generate the CPU clocks. The
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MP-09 CPU board retained the MC14411 at first, but provided an
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independent XTAL for the MC6809 and jumpers to select higher
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baud rates. Later the MC14411 was removed from the CPU board so
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the five baud rate lines on the 50-pin bus could be reused to
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provide 20-bit addressing and DMA. This was accomplished by
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adding a separate MP-ID Interface Driver Board to decode I/O
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accesses (and optionally slow them down to allow old 1 MHz
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peripherals to be used with a faster CPU), generate the baud
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rates (whose selection was changed yet again) from a dedicated
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MC14411, and provide a few I/O functions of its own.
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***********************************************************************
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+-+
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30 |o| RS2 (originally UD3)
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29 |o| RS3 (originally UD4)
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28 |o| -16V (originally -12V)
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27 |o| +16V (originally +12V)
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26 |o| GND
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25 |o| GND
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24 |o| INDEX
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23 |o| /FIRQ (6800: /NMI)
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22 |o| /IRQ
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21 |o| RS0
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20 |o| RS1
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19 |o| D0
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18 |o| D1
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17 |o| D2
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16 |o| D3
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15 |o| D4
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14 |o| D5
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13 |o| D6
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12 |o| D7
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11 |o| E (6800: ϕ2)
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10 |o| R/W
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9 |o| +8V (unregulated)
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8 |o| +8V (unregulated)
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7 |o| 600b/1200b (originally 1200b)
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6 |o| 4800b (originally 600b)
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5 |o| 300b
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4 |o| 150b/9600b (originally 150b)
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3 |o| 110b
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2 |o| /RESET
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1 |o| I/O #
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+-+
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**********************************************************************/
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#include "emu.h"
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#include "bus/ss50/interface.h"
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#include "bus/ss50/mpc.h"
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//#include "bus/ss50/mpl.h"
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//#include "bus/ss50/mpr.h"
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#include "bus/ss50/mps.h"
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#include "bus/ss50/mps2.h"
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#include "bus/ss50/mpt.h"
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#include "bus/ss50/piaide.h"
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//**************************************************************************
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// GLOBAL VARIABLES
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//**************************************************************************
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// device type definition
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DEFINE_DEVICE_TYPE(SS50_INTERFACE, ss50_interface_port_device, "ss50_interface", "SS-50 Interface Port")
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//**************************************************************************
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// SS-50 INTERFACE PORT DEVICE
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//**************************************************************************
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//-------------------------------------------------
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// ss50_interface_port_device - construction
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//-------------------------------------------------
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ss50_interface_port_device::ss50_interface_port_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
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: device_t(mconfig, SS50_INTERFACE, tag, owner, clock),
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device_slot_interface(mconfig, *this),
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m_irq_cb(*this),
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m_firq_cb(*this),
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m_card(nullptr)
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{
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}
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//-------------------------------------------------
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// device_resolve_objects - resolve objects that
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// may be needed for other devices to set
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// initial conditions at start time
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//-------------------------------------------------
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void ss50_interface_port_device::device_resolve_objects()
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{
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logerror("Resolving objects...\n");
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m_irq_cb.resolve_safe();
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m_firq_cb.resolve_safe();
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m_card = dynamic_cast<ss50_card_interface *>(get_card_device());
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if (m_card != nullptr)
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m_card->m_slot = this;
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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 ss50_interface_port_device::device_start()
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{
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}
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//-------------------------------------------------
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// read - interface read access (pre-decoded)
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//-------------------------------------------------
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u8 ss50_interface_port_device::read(offs_t offset)
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{
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if (m_card == nullptr)
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{
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logerror("%s: Read from unspecified interface (RS = %X)\n", machine().describe_context(), offset);
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return 0xff;
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}
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return m_card->register_read(offset);
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}
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//-------------------------------------------------
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// write - interface write access (pre-decoded)
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//-------------------------------------------------
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void ss50_interface_port_device::write(offs_t offset, u8 data)
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{
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if (m_card == nullptr)
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{
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logerror("%s: Write to unspecified interface (RS = %X, D = %02X)\n", machine().describe_context(), offset, data);
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return;
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}
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m_card->register_write(offset, data);
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}
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//-------------------------------------------------
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// fN_w - baud rate clocks for serial interfaces
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//-------------------------------------------------
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WRITE_LINE_MEMBER(ss50_interface_port_device::f110_w)
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{
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if (m_card != nullptr)
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m_card->f110_w(state);
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}
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WRITE_LINE_MEMBER(ss50_interface_port_device::f150_9600_w)
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{
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if (m_card != nullptr)
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m_card->f150_9600_w(state);
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}
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WRITE_LINE_MEMBER(ss50_interface_port_device::f300_w)
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{
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if (m_card != nullptr)
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m_card->f300_w(state);
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}
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WRITE_LINE_MEMBER(ss50_interface_port_device::f600_4800_w)
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{
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if (m_card != nullptr)
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m_card->f600_4800_w(state);
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}
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WRITE_LINE_MEMBER(ss50_interface_port_device::f600_1200_w)
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{
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if (m_card != nullptr)
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m_card->f600_1200_w(state);
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}
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//**************************************************************************
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// SS-50 CARD INTERFACE
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//**************************************************************************
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template class device_finder<ss50_card_interface, false>;
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template class device_finder<ss50_card_interface, true>;
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//-------------------------------------------------
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// ss50_card_interface - construction
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//-------------------------------------------------
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ss50_card_interface::ss50_card_interface(const machine_config &mconfig, device_t &device)
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: device_slot_card_interface(mconfig, device),
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m_slot(nullptr)
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{
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}
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void ss50_default_2rs_devices(device_slot_interface &device)
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{
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device.option_add("mpc", SS50_MPC);
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//device.option_add("mpl", SS50_MPL);
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//device.option_add("mpn", SS50_MPN);
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device.option_add("mps", SS50_MPS);
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device.option_add("mps2", SS50_MPS2);
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device.option_add("mpt", SS50_MPT);
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device.option_add("piaide", SS50_PIAIDE);
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}
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