Sprinter/mame
2
0
Fork 0
mirror of https://github.com/holub/mame synced 2025-05-21 21:29:15 +03:00
Code Issues Actions 3 Packages Projects Releases Wiki Activity

mos6551: support Rockwell 6551s, which show different register contents from MOS/CSG parts on reset. [R. Belmont]

Browse Source
This commit is contained in:
R. Belmont 2014-02-02 21:51:50 +00:00
parent 99461ab795
commit 7e9c0431c0
2 changed files with 42 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
src/emu/machine/mos6551.c
View File

@ -67,7 +67,8 @@ mos6551_device::mos6551_device(const machine_config &mconfig, const char *tag, d
m_ext_rxc(0),
m_cts(1),
m_dsr(1),
m_dcd(1)
m_dcd(1),
m_chip_type(MOS6551_TYPE_MOS)
{
}
@ -103,7 +104,20 @@ void mos6551_device::device_start()
void mos6551_device::device_reset()
{
m_ctrl = 0;
m_cmd = CMD_RIE;
switch (m_chip_type)
{
case MOS6551_TYPE_MOS:
m_cmd = CMD_RIE;
break;
case MOS6551_TYPE_ROCKWELL:
m_cmd = 0;
break;
default:
fatalerror("mos6551: unknown type %d", m_chip_type);
}
transmit_register_reset();
receive_register_reset();
@ -111,6 +125,16 @@ void mos6551_device::device_reset()
update_serial();
}
//-------------------------------------------------
// static_set_type - configuration helper to set
// the chip type
//-------------------------------------------------
void mos6551_device::static_set_type(device_t &device, int type)
{
mos6551_device &mos = downcast<mos6551_device &>(device);
mos.m_chip_type = type;
}
void mos6551_device::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr)
{
@ -321,7 +345,11 @@ WRITE8_MEMBER( mos6551_device::write )
case 1:
// programmed reset
m_cmd = (m_cmd & 0xe0) | CMD_RIE;
m_cmd = (m_cmd & 0xe0);
if (m_chip_type == MOS6551_TYPE_MOS)
{
m_cmd |= CMD_RIE;
}
m_st &= ~ST_OR;
update_serial();
break;

12
src/emu/machine/mos6551.h
View File

@ -33,7 +33,10 @@
#include "emu.h"
// MOS 6551s reset with the RIE bit set in the command register
#define MOS6551_TYPE_MOS (0)
// Rockwell (and Synertek) reset with all bits clear in the command register
#define MOS6551_TYPE_ROCKWELL (1)
//**************************************************************************
// INTERFACE CONFIGURATION MACROS
@ -51,6 +54,8 @@
#define MCFG_MOS6551_DTR_HANDLER(_devcb) \
devcb = &mos6551_device::set_dtr_handler(*device, DEVCB2_##_devcb);
#define MCFG_MOS6551_TYPE(_type) \
mos6551_device::static_set_type(*device, _type);
//**************************************************************************
@ -82,6 +87,9 @@ public:
void set_rxc(int clock);
// inline configuration helpers
static void static_set_type(device_t &device, int type);
protected:
// device-level overrides
virtual void device_start();
@ -181,6 +189,8 @@ protected:
int m_dsr;
int m_dcd;
int m_chip_type;
static const int brg_divider[16];
};