summaryrefslogtreecommitdiffstatshomepage
path: root/src/mame/machine/nitedrvr.cpp
blob: 500e7bf5e6db44921ce95aa3dc18777d3d19b0dc (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
// license:BSD-3-Clause
// copyright-holders:Mike Balfour
/***************************************************************************

    Atari Night Driver hardware

***************************************************************************/

#include "emu.h"
#include "includes/nitedrvr.h"
#include "sound/discrete.h"

/***************************************************************************
Steering

When D7 is high, the steering wheel has moved.
If D6 is low, it moved left.  If D6 is high, it moved right.
Be sure to keep returning a direction until steering_reset is called,
because D6 and D7 are apparently checked at different times, and a
change in-between can affect the direction you move.
***************************************************************************/

int nitedrvr_state::nitedrvr_steering(  )
{
	int this_val = ioport("STEER")->read();
	int delta = this_val - m_last_steering_val;

	m_last_steering_val = this_val;

	if (delta > 128)
		delta -= 256;
	else if (delta < -128)
		delta += 256;

	/* Divide by four to make our steering less sensitive */
	m_steering_buf += (delta / 4);

	if (m_steering_buf > 0)
	{
		m_steering_buf--;
		m_steering_val = 0xc0;
	}
	else if (m_steering_buf < 0)
	{
		m_steering_buf++;
		m_steering_val = 0x80;
	}
	else
	{
		m_steering_val = 0x00;
	}

	return m_steering_val;
}

/***************************************************************************
nitedrvr_steering_reset
***************************************************************************/

READ8_MEMBER(nitedrvr_state::nitedrvr_steering_reset_r)
{
	m_steering_val = 0;
	return 0;
}

WRITE8_MEMBER(nitedrvr_state::nitedrvr_steering_reset_w)
{
	m_steering_val = 0;
}


/***************************************************************************
nitedrvr_in0_r

Night Driver looks for the following:
    A: $00
        D4 - OPT1
        D5 - OPT2
        D6 - OPT3
        D7 - OPT4
    A: $01
        D4 - TRACK SET
        D5 - BONUS TIME ALLOWED
        D6 - VBLANK
        D7 - !TEST
    A: $02
        D4 - !GEAR 1
        D5 - !GEAR 2
        D6 - !GEAR 3
        D7 - SPARE
    A: $03
        D4 - SPARE
        D5 - DIFFICULT BONUS
        D6 - STEER A
        D7 - STEER B

Fill in the steering and gear bits in a special way.
***************************************************************************/

READ8_MEMBER(nitedrvr_state::nitedrvr_in0_r)
{
	int gear = ioport("GEARS")->read();

	if (gear & 0x10)                m_gear = 1;
	else if (gear & 0x20)           m_gear = 2;
	else if (gear & 0x40)           m_gear = 3;
	else if (gear & 0x80)           m_gear = 4;

	switch (offset & 0x03)
	{
		case 0x00:                      /* No remapping necessary */
			return ioport("DSW0")->read();
		case 0x01:                      /* No remapping necessary */
			return ioport("DSW1")->read();
		case 0x02:                      /* Remap our gear shift */
			if (m_gear == 1)
				return 0xe0;
			else if (m_gear == 2)
				return 0xd0;
			else if (m_gear == 3)
				return 0xb0;
			else
				return 0x70;
		case 0x03:                      /* Remap our steering */
			return (ioport("DSW2")->read() | nitedrvr_steering());
		default:
			return 0xff;
	}
}

/***************************************************************************
nitedrvr_in1_r

Night Driver looks for the following:
    A: $00
        D6 - SPARE
        D7 - COIN 1
    A: $01
        D6 - SPARE
        D7 - COIN 2
    A: $02
        D6 - SPARE
        D7 - !START
    A: $03
        D6 - SPARE
        D7 - !ACC
    A: $04
        D6 - SPARE
        D7 - EXPERT
    A: $05
        D6 - SPARE
        D7 - NOVICE
    A: $06
        D6 - SPARE
        D7 - Special Alternating Signal
    A: $07
        D6 - SPARE
        D7 - Ground

Fill in the track difficulty switch and special signal in a special way.
***************************************************************************/

READ8_MEMBER(nitedrvr_state::nitedrvr_in1_r)
{
	int port = ioport("IN0")->read();

	m_ac_line = (m_ac_line + 1) % 3;

	if (port & 0x10)                m_track = 0;
	else if (port & 0x20)           m_track = 1;
	else if (port & 0x40)           m_track = 2;

	switch (offset & 0x07)
	{
		case 0x00:
			return ((port & 0x01) << 7);
		case 0x01:
			return ((port & 0x02) << 6);
		case 0x02:
			return ((port & 0x04) << 5);
		case 0x03:
			return ((port & 0x08) << 4);
		case 0x04:
			if (m_track == 1) return 0x80; else return 0x00;
		case 0x05:
			if (m_track == 0) return 0x80; else return 0x00;
		case 0x06:
			/* TODO: fix alternating signal? */
			if (m_ac_line==0) return 0x80; else return 0x00;
		case 0x07:
			return 0x00;
		default:
			return 0xff;
	}
}

/***************************************************************************
nitedrvr_out0_w

Sound bits:

D0 = !SPEED1
D1 = !SPEED2
D2 = !SPEED3
D3 = !SPEED4
D4 = SKID1
D5 = SKID2
***************************************************************************/

WRITE8_MEMBER(nitedrvr_state::nitedrvr_out0_w)
{
	m_discrete->write(NITEDRVR_MOTOR_DATA, data & 0x0f);  // Motor freq data
	m_discrete->write(NITEDRVR_SKID1_EN, data & 0x10);    // Skid1 enable
	m_discrete->write(NITEDRVR_SKID2_EN, data & 0x20);    // Skid2 enable
}

/***************************************************************************
nitedrvr_out1_w

D0 = !CRASH - also drives a video invert signal
D1 = ATTRACT
D2 = Spare (Not used)
D3 = Not used?
D4 = LED START
D5 = Spare (Not used)
***************************************************************************/

WRITE8_MEMBER(nitedrvr_state::nitedrvr_out1_w)
{
	m_led = BIT(data, 4);

	m_crash_en = data & 0x01;

	m_discrete->write(NITEDRVR_CRASH_EN, m_crash_en); // Crash enable
	m_discrete->write(NITEDRVR_ATTRACT_EN, data & 0x02);      // Attract enable (sound disable)

	if (!m_crash_en)
	{
		/* Crash reset, set counter high and enable output */
		m_crash_data_en = 1;
		m_crash_data = 0x0f;
		/* Invert video */
		m_palette->set_pen_color(1, rgb_t(0x00,0x00,0x00)); /* BLACK */
		m_palette->set_pen_color(0, rgb_t(0xff,0xff,0xff)); /* WHITE */
	}
	m_discrete->write(NITEDRVR_BANG_DATA, m_crash_data_en ? m_crash_data : 0);    // Crash Volume
}


TIMER_DEVICE_CALLBACK_MEMBER(nitedrvr_state::nitedrvr_crash_toggle_callback)
{
	if (m_crash_en && m_crash_data_en)
	{
		m_crash_data--;
		m_discrete->write(NITEDRVR_BANG_DATA, m_crash_data);  // Crash Volume
		if (!m_crash_data)
			m_crash_data_en = 0;    // Done counting?

		if (m_crash_data & 0x01)
		{
			/* Invert video */
			m_palette->set_pen_color(1, rgb_t(0x00,0x00,0x00)); /* BLACK */
			m_palette->set_pen_color(0, rgb_t(0xff,0xff,0xff)); /* WHITE */
		}
		else
		{
			/* Normal video */
			m_palette->set_pen_color(0, rgb_t(0x00,0x00,0x00)); /* BLACK */
			m_palette->set_pen_color(1, rgb_t(0xff,0xff,0xff)); /* WHITE */
		}
	}
}

void nitedrvr_state::machine_start()
{
	m_led.resolve();

	save_item(NAME(m_gear));
	save_item(NAME(m_track));
	save_item(NAME(m_steering_buf));
	save_item(NAME(m_steering_val));
	save_item(NAME(m_crash_en));
	save_item(NAME(m_crash_data));
	save_item(NAME(m_crash_data_en));
	save_item(NAME(m_ac_line));
	save_item(NAME(m_last_steering_val));
}

void nitedrvr_state::machine_reset()
{
	m_gear = 1;
	m_track = 0;
	m_steering_buf = 0;
	m_steering_val = 0;
	m_crash_en = 0;
	m_crash_data = 0x0f;
	m_crash_data_en = 0;
	m_ac_line = 0;
	m_last_steering_val = 0;
}