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
|
// license:BSD-3-Clause
// copyright-holders:Nigel Barnes
/***************************************************************************
Advanced Quarter Meg Ram
***************************************************************************/
#include "emu.h"
#include "aqr.h"
//**************************************************************************
// DEVICE DEFINITIONS
//**************************************************************************
DEFINE_DEVICE_TYPE(ELECTRON_AQR, electron_aqr_device, "electron_aqr", "Electron Advanced Quarter Meg Ram cartridge")
//**************************************************************************
// LIVE DEVICE
//**************************************************************************
//-------------------------------------------------
// electron_aqr_device - constructor
//-------------------------------------------------
electron_aqr_device::electron_aqr_device(const machine_config &mconfig, const char *tag, device_t *owner, const XTAL &clock)
: device_t(mconfig, ELECTRON_AQR, tag, owner, clock)
, device_electron_cart_interface(mconfig, *this)
, m_page_register(0)
, m_lock_register(false)
{
}
//-------------------------------------------------
// device_start - device-specific startup
//-------------------------------------------------
void electron_aqr_device::device_start()
{
save_item(NAME(m_page_register));
save_item(NAME(m_lock_register));
}
//-------------------------------------------------
// read - cartridge data read
//-------------------------------------------------
uint8_t electron_aqr_device::read(offs_t offset, int infc, int infd, int romqa, int oe, int oe2)
{
uint8_t data = 0xff;
if (oe)
{
data = m_ram[(offset & 0x3fff) | (m_page_register << 14)];
}
return data;
}
//-------------------------------------------------
// write - cartridge data write
//-------------------------------------------------
void electron_aqr_device::write(offs_t offset, uint8_t data, int infc, int infd, int romqa, int oe, int oe2)
{
if (infc)
{
switch (offset & 0xff)
{
case 0xfc:
m_page_register = data;
break;
case 0xfd:
m_lock_register = false;
break;
case 0xfe:
m_lock_register = true;
break;
}
}
else if (oe)
{
m_ram[(offset & 0x3fff) | (m_page_register << 14)] = data;
}
}
|