1 // license:BSD-3-Clause
2 // copyright-holders:Curt Coder
3 /**********************************************************************
4 
5     C64 switchable 8K cartridge emulation
6 
7 **********************************************************************/
8 
9 /*
10 
11     4040 + Fast Hack'em
12 
13     PCB Layout
14     ----------
15 
16     |===========================|
17     |=|                         |
18     |=|                     SW1 |
19     |=|         ROM0            |
20     |=|                         |
21     |=|                         |
22     |=|         ROM1            |
23     |=|                         |
24     |=|                         |
25     |===========================|
26 
27     ROM0,1  - National Semiconductor NMC27C64Q 8Kx8 EPROM
28     SW1     - ROM selection switch
29 
30 */
31 
32 #include "emu.h"
33 #include "sw8k.h"
34 
35 
36 
37 //**************************************************************************
38 //  DEVICE DEFINITIONS
39 //**************************************************************************
40 
41 DEFINE_DEVICE_TYPE(C64_SW8K, c64_switchable_8k_cartridge_device, "c64_sw8k", "C64 Switchable 8K cartridge")
42 
43 
44 //-------------------------------------------------
45 //  INPUT_PORTS( c64_easyflash )
46 //-------------------------------------------------
47 
INPUT_PORTS_START(c64_switchable_8k)48 static INPUT_PORTS_START( c64_switchable_8k )
49 	PORT_START("SW")
50 	PORT_DIPNAME( 0x01, 0x00, "ROM Select" )
51 	PORT_DIPSETTING(    0x00, "ROM 0" )
52 	PORT_DIPSETTING(    0x01, "ROM 1" )
53 INPUT_PORTS_END
54 
55 
56 //-------------------------------------------------
57 //  input_ports - device-specific input ports
58 //-------------------------------------------------
59 
60 ioport_constructor c64_switchable_8k_cartridge_device::device_input_ports() const
61 {
62 	return INPUT_PORTS_NAME( c64_switchable_8k );
63 }
64 
65 
66 
67 //**************************************************************************
68 //  LIVE DEVICE
69 //**************************************************************************
70 
71 //-------------------------------------------------
72 //  c64_switchable_8k_cartridge_device - constructor
73 //-------------------------------------------------
74 
c64_switchable_8k_cartridge_device(const machine_config & mconfig,const char * tag,device_t * owner,uint32_t clock)75 c64_switchable_8k_cartridge_device::c64_switchable_8k_cartridge_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
76 	device_t(mconfig, C64_SW8K, tag, owner, clock),
77 	device_c64_expansion_card_interface(mconfig, *this),
78 	m_sw(*this, "SW"), m_bank(0)
79 {
80 }
81 
82 
83 //-------------------------------------------------
84 //  device_start - device-specific startup
85 //-------------------------------------------------
86 
device_start()87 void c64_switchable_8k_cartridge_device::device_start()
88 {
89 }
90 
91 
92 //-------------------------------------------------
93 //  device_reset - device-specific reset
94 //-------------------------------------------------
95 
device_reset()96 void c64_switchable_8k_cartridge_device::device_reset()
97 {
98 	m_bank = m_sw->read();
99 }
100 
101 
102 //-------------------------------------------------
103 //  c64_cd_r - cartridge data read
104 //-------------------------------------------------
105 
c64_cd_r(offs_t offset,uint8_t data,int sphi2,int ba,int roml,int romh,int io1,int io2)106 uint8_t c64_switchable_8k_cartridge_device::c64_cd_r(offs_t offset, uint8_t data, int sphi2, int ba, int roml, int romh, int io1, int io2)
107 {
108 	if (!roml)
109 	{
110 		offs_t addr = (m_bank << 13) | (offset & 0x1fff);
111 		data = m_roml[addr];
112 	}
113 
114 	return data;
115 }
116