summaryrefslogtreecommitdiffstatshomepage
path: root/src/devices/bus/a2bus/a2echoii.cpp
blob: 6e911dc5bde55ce15a42502b3c631a194da1f049 (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
// license:BSD-3-Clause
// copyright-holders:R. Belmont
/*********************************************************************

    a2echoii.c

    Implementation of the Street Electronics Echo II speech card
    Ready logic traced by Jonathan Gevaryahu

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

#include "emu.h"
#include "a2echoii.h"
#include "sound/tms5220.h"
#include "speaker.h"

/***************************************************************************
    PARAMETERS
***************************************************************************/

//**************************************************************************
//  GLOBAL VARIABLES
//**************************************************************************

DEFINE_DEVICE_TYPE(A2BUS_ECHOII, a2bus_echoii_device, "a2echoii", "Street Electronics Echo II")

#define TMS_TAG         "tms5220"

/***************************************************************************
    FUNCTION PROTOTYPES
***************************************************************************/

//-------------------------------------------------
//  device_add_mconfig - add device configuration
//-------------------------------------------------

MACHINE_CONFIG_START(a2bus_echoii_device::device_add_mconfig)
	SPEAKER(config, "echoii").front_center();
	MCFG_DEVICE_ADD(TMS_TAG, TMS5220, 640000) // Note the Echo II card has a "FREQ" potentiometer which can be used to adjust the tms5220's clock frequency; 640khz is the '8khz' value according to the tms5220 datasheet
	MCFG_TMS52XX_READYQ_HANDLER(WRITELINE(*this, a2bus_echoii_device, ready_w))
	MCFG_SOUND_ROUTE(ALL_OUTPUTS, "echoii", 1.0)
MACHINE_CONFIG_END

//**************************************************************************
//  LIVE DEVICE
//**************************************************************************

a2bus_echoii_device::a2bus_echoii_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, uint32_t clock) :
	device_t(mconfig, type, tag, owner, clock),
	device_a2bus_card_interface(mconfig, *this),
	m_tms(*this, TMS_TAG)
{
}

a2bus_echoii_device::a2bus_echoii_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
	a2bus_echoii_device(mconfig, A2BUS_ECHOII, tag, owner, clock)
{
}

//-------------------------------------------------
//  device_start - device-specific startup
//-------------------------------------------------

void a2bus_echoii_device::device_start()
{
	m_timer = timer_alloc(0);
	m_timer->adjust(attotime::never);

	save_item(NAME(m_latch));
	save_item(NAME(m_ready));
	save_item(NAME(m_byte_in_latch));
}

void a2bus_echoii_device::device_reset()
{
	m_byte_in_latch = false;
	m_ready = 0;
	m_latch = 0;
}

uint8_t a2bus_echoii_device::read_c0nx(uint8_t offset)
{
	switch (offset)
	{
		case 0:
			return 0x1f | m_tms->status_r();
	}

	return 0;
}

void a2bus_echoii_device::write_c0nx(uint8_t offset, uint8_t data)
{
	switch (offset)
	{
		case 0:
			m_latch = data;
			if (!m_ready)
			{
				m_tms->data_w(m_latch);
			}
			else
			{
				m_byte_in_latch = true;
			}
			break;
	}
}

bool a2bus_echoii_device::take_c800()
{
	return false;
}

void a2bus_echoii_device::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr)
{
	m_tms->data_w(m_latch);
	m_byte_in_latch = false;
	m_timer->adjust(attotime::never);
}

WRITE_LINE_MEMBER( a2bus_echoii_device::ready_w )
{
	// if /Ready falls, write the byte in the latch if there is one
	if ((m_ready) && (!state) && (m_byte_in_latch))
	{
		m_timer->adjust(attotime::zero);
	}

	m_ready = state;
}