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Implemented proper vblank read-back on Aristocrat Mk-4 HW [Angelo Salese]

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Angelo Salese 2011-03-01 18:48:41 +00:00
parent c540088b81
commit f5a3299392
1 changed files with 13 additions and 30 deletions
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43
src/mame/drivers/aristmk4.c
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@ -143,6 +143,10 @@
9.When DIP SW7 is set to off/off, speed is dramatically reduced.
10. rewrite video emulation by using custom drawing code.
11. check what type of mc6845 this HW uses on real PCB, and hook it up properly.
***************** POKER GAMES ************************************************************************
Wild One & Golden Poker have a problem where the second branch condition is always true, see assebler below for
@ -158,6 +162,11 @@
Bug in the 6845 crtc core ? Seems like some kind of logic there not working.
EDIT: it's a vblank check, BITA opcode checks bit 5 in A register and compares it with the contents of 0x1800 (that is vblank in
mc6845_status_r). Checking if a bit goes low then high it usually means that is moaning for a vblank. ;-)
But now there is a new question: what kind of mc6845 clone this HW uses? It's clearly not standard mc6845, since that version doesn't
support vblank reading. The vblank bit can be read only on C6545-1, R6545-1, SY6545-1 and SY6845E subvariants, so it all lies to
those. -AS
***********************************************************************************************************************************************/
@ -178,8 +187,6 @@
#include "machine/nvram.h"
UINT8 crtc_cursor_index = 0;
UINT8 crtc_cursor[2] = {0x00,0xff};
UINT8 crtc_select = 0;
UINT8 crtc_reg = 0;
class aristmk4_state : public driver_device
@ -782,7 +789,7 @@ static READ8_HANDLER(mk4_printer_r)
static ADDRESS_MAP_START( aristmk4_map, ADDRESS_SPACE_PROGRAM, 8 )
AM_RANGE(0x0000, 0x07ff) AM_RAM AM_BASE_MEMBER(aristmk4_state, mkiv_vram) // video ram - chips U49 / U50
AM_RANGE(0x0800, 0x17ff) AM_RAM
AM_RANGE(0x1800, 0x1800) AM_DEVWRITE("crtc", mc6845_address_w)
AM_RANGE(0x1800, 0x1800) AM_DEVREADWRITE("crtc", mc6845_status_r, mc6845_address_w)
AM_RANGE(0x1801, 0x1801) AM_DEVREADWRITE("crtc", mc6845_register_r, mc6845_register_w)
AM_RANGE(0x1c00, 0x1cff) AM_WRITE(mk4_printer_w)
AM_RANGE(0x1900, 0x19ff) AM_READ(mk4_printer_r)
@ -829,30 +836,6 @@ so a work around is required.
*/
READ8_DEVICE_HANDLER( aristmk4_crtc_r )
{
// just give the cursor values expected 0x00 & 0xff. Otherwise 0x00 is always read
// and game will not start
if(crtc_reg == 0x0f) // work around
return crtc_cursor[crtc_cursor_index++%2];
else
return mc6845_register_r(device, 0);
}
WRITE8_DEVICE_HANDLER( aristmk4_crtc_w )
{
if(crtc_select == 0)
{
crtc_reg = data;
mc6845_address_w(device, 0, data);
}
else
mc6845_register_w(device, 0, data);
crtc_select ^= 1;
}
/*
Poker card style games seem to have different address mapping
@ -868,8 +851,8 @@ The U87 personality rom is not required, therefore game rom code mapping is from
static ADDRESS_MAP_START( aristmk4_poker_map, ADDRESS_SPACE_PROGRAM, 8 )
AM_RANGE(0x0000, 0x07ff) AM_RAM AM_BASE_MEMBER(aristmk4_state, mkiv_vram) // video ram - chips U49 / U50
AM_RANGE(0x0800, 0x17ff) AM_RAM
AM_RANGE(0x1800, 0x1800) AM_DEVREADWRITE("crtc", aristmk4_crtc_r, aristmk4_crtc_w)
AM_RANGE(0x1801, 0x1801) AM_DEVREADWRITE("crtc", aristmk4_crtc_r, aristmk4_crtc_w)
AM_RANGE(0x1800, 0x1800) AM_DEVREADWRITE("crtc", mc6845_status_r, mc6845_address_w)
AM_RANGE(0x1801, 0x1801) AM_DEVREADWRITE("crtc", mc6845_register_r, mc6845_register_w)
AM_RANGE(0x1c00, 0x1cff) AM_WRITE(mk4_printer_w)
AM_RANGE(0x1900, 0x19ff) AM_READ(mk4_printer_r)
AM_RANGE(0x6000, 0x7fff) AM_ROM // graphics rom map
@ -1560,7 +1543,7 @@ static MACHINE_CONFIG_START( aristmk4, aristmk4_state )
MCFG_PPI8255_ADD( "ppi8255_0", ppi8255_intf1 )
MCFG_VIA6522_ADD("via6522_0", 0, via_interface) /* 1 MHz.(only 1 or 2 MHz.are valid) */
MCFG_PIA6821_ADD("pia6821_0", aristmk4_pia1_intf)
MCFG_MC6845_ADD("crtc", MC6845, MAIN_CLOCK/8, mc6845_intf)
MCFG_MC6845_ADD("crtc", C6545_1, MAIN_CLOCK/8, mc6845_intf) // TODO: type is unknown
MCFG_MC146818_ADD("rtc", MC146818_IGNORE_CENTURY)
MCFG_SPEAKER_STANDARD_MONO("mono")