1 // license:BSD-3-Clause
2 // copyright-holders:Curt Coder
3 /**********************************************************************
4
5 SilverRock Productions cartridge emulation
6
7 **********************************************************************/
8
9 /*
10
11 PCB Layout
12 ----------
13
14 e9048
15 |=============|
16 |=| LS00 |
17 |=| LS273|
18 |=| |
19 |=| |
20 |=| ROM |
21 |=| |
22 |=| |
23 |=| |
24 |=============|
25
26 ROM - Atmel AT27C010-25PC 128Kx8 OTP EPROM "HUGO 2012"
27
28 */
29
30 #include "emu.h"
31 #include "silverrock.h"
32
33
34
35 //**************************************************************************
36 // MACROS/CONSTANTS
37 //**************************************************************************
38
39 #define UNSCRAMBLE_ADDRESS(_offset) \
40 bitswap<16>(_offset,15,14,13,12,1,0,2,3,11,10,9,8,7,6,5,4)
41
42 #define UNSCRAMBLE_DATA(_data) \
43 bitswap<8>(_data,7,6,5,4,0,1,2,3)
44
45
46
47 //**************************************************************************
48 // DEVICE DEFINITIONS
49 //**************************************************************************
50
51 DEFINE_DEVICE_TYPE(C64_SILVERROCK, c64_silverrock_cartridge_device, "c64_silverrock", "C64 SilverRock cartridge")
52
53
54
55 //**************************************************************************
56 // LIVE DEVICE
57 //**************************************************************************
58
59 //-------------------------------------------------
60 // c64_silverrock_cartridge_device - constructor
61 //-------------------------------------------------
62
c64_silverrock_cartridge_device(const machine_config & mconfig,const char * tag,device_t * owner,uint32_t clock)63 c64_silverrock_cartridge_device::c64_silverrock_cartridge_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
64 device_t(mconfig, C64_SILVERROCK, tag, owner, clock),
65 device_c64_expansion_card_interface(mconfig, *this), m_bank(0)
66 {
67 }
68
69
70 //-------------------------------------------------
71 // device_start - device-specific startup
72 //-------------------------------------------------
73
device_start()74 void c64_silverrock_cartridge_device::device_start()
75 {
76 // state saving
77 save_item(NAME(m_bank));
78 }
79
80
81 //-------------------------------------------------
82 // device_reset - device-specific reset
83 //-------------------------------------------------
84
device_reset()85 void c64_silverrock_cartridge_device::device_reset()
86 {
87 m_bank = 0;
88 }
89
90
91 //-------------------------------------------------
92 // c64_cd_r - cartridge data read
93 //-------------------------------------------------
94
c64_cd_r(offs_t offset,uint8_t data,int sphi2,int ba,int roml,int romh,int io1,int io2)95 uint8_t c64_silverrock_cartridge_device::c64_cd_r(offs_t offset, uint8_t data, int sphi2, int ba, int roml, int romh, int io1, int io2)
96 {
97 if (!roml)
98 {
99 offs_t addr = (m_bank << 13) | (offset & 0x1fff);
100 addr = (addr & 0x10000) | UNSCRAMBLE_ADDRESS(addr);
101 data = UNSCRAMBLE_DATA(m_roml[addr]);
102 }
103
104 return data;
105 }
106
107
108 //-------------------------------------------------
109 // c64_cd_w - cartridge data write
110 //-------------------------------------------------
111
c64_cd_w(offs_t offset,uint8_t data,int sphi2,int ba,int roml,int romh,int io1,int io2)112 void c64_silverrock_cartridge_device::c64_cd_w(offs_t offset, uint8_t data, int sphi2, int ba, int roml, int romh, int io1, int io2)
113 {
114 if (!io1)
115 {
116 /*
117
118 bit description
119
120 0
121 1
122 2
123 3
124 4 A14
125 5 A15
126 6 A16
127 7 A13
128
129 */
130
131 m_bank = ((data >> 3) & 0x0e) | BIT(data, 7);
132 }
133 }
134