1 // license:BSD-3-Clause
2 // copyright-holders:AJR
3 /**********************************************************************
4
5 VS9209 (4L01F1429) custom QFP80 I/O
6
7 This chip, which appears on various Video System PCBs from 1992
8 to 1995, provides a programmable interface for up to eight ports.
9
10 There are at least four configuration registers that control the
11 directions of individual bits on some of the ports (low for input
12 and high for output). However, the game programs always write
13 zero to the first register, except for Super Slams which doesn't
14 write to it at all.
15
16 No program attempts to write to Ports A, B, C or D, with the
17 dubious exception of Tao Taido writing to the Port C offset on
18 its second VS9209 (whose inputs are mostly unused) at
19 initialization time. It seems possible that only the latter four
20 ports may be configured for output.
21
22 Much like CXD1095, the last port is apparently only half width.
23
24 **********************************************************************/
25
26 #include "emu.h"
27 #include "machine/vs9209.h"
28
29 //**************************************************************************
30 // GLOBAL VARIABLES
31 //**************************************************************************
32
33 DEFINE_DEVICE_TYPE(VS9209, vs9209_device, "vs9209", "VS9209 I/O")
34
35 //**************************************************************************
36 // DEVICE DEFINITION
37 //**************************************************************************
38
39 //-------------------------------------------------
40 // vs9209_device - constructor
41 //-------------------------------------------------
42
vs9209_device(const machine_config & mconfig,const char * tag,device_t * owner,u32 clock)43 vs9209_device::vs9209_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
44 : device_t(mconfig, VS9209, tag, owner, clock)
45 , m_input_cb(*this)
46 , m_output_cb(*this)
47 {
48 }
49
50 //-------------------------------------------------
51 // device_start - device-specific startup
52 //-------------------------------------------------
53
device_start()54 void vs9209_device::device_start()
55 {
56 // resolve callbacks
57 m_input_cb.resolve_all();
58 m_output_cb.resolve_all();
59
60 std::fill(std::begin(m_data_latch), std::end(m_data_latch), 0);
61
62 // save state
63 save_item(NAME(m_data_latch));
64 save_item(NAME(m_data_dir));
65 }
66
67 //-------------------------------------------------
68 // device_reset - device-specific reset
69 //-------------------------------------------------
70
device_reset()71 void vs9209_device::device_reset()
72 {
73 std::fill(std::begin(m_data_dir), std::end(m_data_dir), 0);
74 }
75
76 //-------------------------------------------------
77 // read - read from an input port
78 //-------------------------------------------------
79
read(address_space & space,offs_t offset)80 u8 vs9209_device::read(address_space &space, offs_t offset)
81 {
82 int port = offset & 7;
83
84 if ((offset & 8) == 0)
85 {
86 u8 input_data = 0;
87 u8 input_mask = ~m_data_dir[port];
88 if (port == 7)
89 input_mask &= 0x0f;
90
91 // read through callback if port not configured entirely for output
92 if (input_mask != 0 && !m_input_cb[port].isnull())
93 input_data = m_input_cb[port](0, input_mask) & input_mask;
94 else if (m_data_dir[port] == 0)
95 logerror("%s: Read from undefined input port %c\n", machine().describe_context(), 'A' + port);
96
97 // combine live inputs with latched data
98 return input_data | (m_data_latch[port] & m_data_dir[port]);
99 }
100
101 //logerror("%s: Read from write-only/nonexistent register %d\n", machine().describe_context(), offset);
102 return space.unmap();
103 }
104
105 //-------------------------------------------------
106 // write - write to an output port or one of two
107 // control registers
108 //-------------------------------------------------
109
write(offs_t offset,u8 data)110 void vs9209_device::write(offs_t offset, u8 data)
111 {
112 // port H is probably only 4 bits wide
113 int port = offset & 7;
114 if (port == 7 && (data & 0xf0) != 0)
115 {
116 logerror("%s: Attempt to write %02X to port H%s", machine().describe_context(), data, (offset & 8) != 0 ? " direction register" : "");
117 data &= 0x0f;
118 }
119
120 if ((offset & 8) == 0)
121 {
122 // update our latched data
123 m_data_latch[port] = data;
124
125 if (m_data_dir[port] != 0)
126 {
127 u8 dataout = data & m_data_dir[port];
128
129 // send output through callback
130 if (!m_output_cb[port].isnull())
131 m_output_cb[port](0, dataout, m_data_dir[port]);
132 else
133 logerror("%s: Writing %02X to undefined output port %c\n", machine().describe_context(), dataout, 'A' + port);
134 }
135 else if (m_output_cb[port].isnull())
136 logerror("%s: Writing %02X to input-only port %c\n", machine().describe_context(), data, 'A' + port);
137 }
138 else
139 {
140 u8 old_data_dir = m_data_dir[port];
141 m_data_dir[port] = data;
142
143 u8 all_port_bits = (port == 7) ? 0x0f : 0xff;
144 if (data != all_port_bits)
145 logerror("Port %c & %02X configured for input\n", 'A' + port, all_port_bits ^ data);
146 if (data != 0)
147 {
148 logerror("Port %c & %02X configured for output\n", 'A' + port, data);
149
150 // if direction changed to output, begin output from latch
151 if ((data & ~old_data_dir) != 0 && !m_output_cb[port].isnull())
152 m_output_cb[port](0, m_data_latch[port], data);
153 }
154 }
155 }
156