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use more likely clocks for littlerb based on PCB XTALS (Main CPU is more likely 8MHz than 12Mhz)

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also use a hack to overclock the TMS to 120% so that the map screen renders properly, points at possible timing errors in the core?
This commit is contained in:
David Haywood 2017-06-02 20:43:58 +01:00
parent ee89e6e997
commit 4d58cf90fa
2 changed files with 11 additions and 9 deletions
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17
src/mame/drivers/littlerb.cpp
View File

@ -103,6 +103,7 @@ public:
TIMER_DEVICE_CALLBACK_MEMBER(littlerb_sound_step_cb);
TIMER_DEVICE_CALLBACK_MEMBER(littlerb_sound_cb);
DECLARE_DRIVER_INIT(littlerb);
};
@ -249,14 +250,14 @@ TIMER_DEVICE_CALLBACK_MEMBER(littlerb_state::littlerb_sound_step_cb)
}
static MACHINE_CONFIG_START( littlerb )
MCFG_CPU_ADD("maincpu", M68000, 12000000)
MCFG_CPU_ADD("maincpu", M68000, XTAL_16MHz/2) // 10MHz rated part, near 16Mhz XTAL
MCFG_CPU_PROGRAM_MAP(littlerb_main)
MCFG_INDER_VIDEO_ADD("inder_vid")
MCFG_INDER_VIDEO_ADD("inder_vid") // XTAL_40MHz
// should probably be done with a timer rather than relying on screen(!)
MCFG_TIMER_DRIVER_ADD_PERIODIC("step_timer", littlerb_state, littlerb_sound_step_cb, attotime::from_hz(7500/150)) // TODO: not accurate
MCFG_TIMER_DRIVER_ADD_PERIODIC("sound_timer", littlerb_state, littlerb_sound_cb, attotime::from_hz(7500)) // TODO: not accurate
// TODO: not accurate - driven by XTAL_6MHz?
MCFG_TIMER_DRIVER_ADD_PERIODIC("step_timer", littlerb_state, littlerb_sound_step_cb, attotime::from_hz(7500/150))
MCFG_TIMER_DRIVER_ADD_PERIODIC("sound_timer", littlerb_state, littlerb_sound_cb, attotime::from_hz(7500))
MCFG_SPEAKER_STANDARD_STEREO("lspeaker","rspeaker")
@ -277,5 +278,9 @@ ROM_START( littlerb )
ROM_LOAD( "romd.u32", 0x00000, 0x40000, CRC(d6b81583) SHA1(b7a63d18a41ccac4d3db9211de0b0cdbc914317a) )
ROM_END
DRIVER_INIT_MEMBER(littlerb_state,littlerb)
{
m_indervid->subdevice<cpu_device>("tms")->set_clock_scale(1.2f);
}
GAME( 1994, littlerb, 0, littlerb, littlerb, littlerb_state, 0, ROT0, "TCH", "Little Robin", MACHINE_IMPERFECT_GRAPHICS|MACHINE_IMPERFECT_SOUND )
GAME( 1994, littlerb, 0, littlerb, littlerb, littlerb_state, littlerb, ROT0, "TCH", "Little Robin", MACHINE_IMPERFECT_GRAPHICS|MACHINE_IMPERFECT_SOUND )

3
src/mame/machine/inder_vid.cpp
View File

@ -2,9 +2,6 @@
// copyright-holders:David Haywood
/* Inder / Dinamic Video */
/* Inder / Dinamic Sound Board */
#include "emu.h"
#include "machine/inder_vid.h"