/* * ============================================================================ * The STIC and System RAM control access to the GRAM, GROM and STIC * registers. The STIC also occasionally stalls the CPU with BUSRQ * so it can fetch display cards from System RAM. The STIC also * interrupts the CPU every time it reaches the bottom of the frame. * * The following parameters control the STIC timing for interrupts and * bus requests. * * FRAMCLKS Cycles between interrupts. * * INTRQ_HOLD How long STIC asserts INTRQ for. If the CPU * masks interrupts too long, it'll drop an interrupt. * * BUSRQ_HOLD_* How long the STIC holds BUSRQ for. FIRST and NORMAL * refer to the first BUSRQ of the frame and the BUSRQs * in the body of the frame. EXTRA refers to the 14th * BUSRQ that occurs when vertical delay == 0. * * MUST_BUSAK_TIME The cycle by which the CPU must respond to a BUSRQ. * If the CPU doesn't respond in time, the System RAM * won't advance the display FIFO and a display glitch * results. * * * When the display's active, the STIC has three main phases: * * -- VBlank 1, where CPU can access both GRAM/GROM and STIC registers * -- VBlank 2, where CPU can access only GRAM/GROM * -- Active display, where the CPU can access neither GRAM/GROM nor * STIC registers. The STIC periodically stalls the CPU for * BACKTAB fetches from System RAM. * * The following paramters define these periods: * * STIC_ACCESSIBLE Time window when STIC registers are accessible * GMEM_ACCESSIBLE Time window when GRAM/GROM are accessible * * * And finally, the first frame after reset has different timing than the * rest. This actually affects a couple games with strange race conditions. * INITIAL_OFFSET says how many cycles to start into the first frame. This * mainly controls where the first interrupt happens, since it's unlikely * any program will get in there fast enough to enable display, unless you * use a custom EXEC with "MVO R0, $20" in the first couple instructions. * * ============================================================================ */ #ifndef STIC_TIMINGS_H_ #define STIC_TIMINGS_H_ 1 #define NTSC_FRAMCLKS (14934) /*#define NTSC_INTRQ_HOLD (2920)*/ #define NTSC_INTRQ_HOLD (2907) /* from Kevin Horton */ #define NTSC_BUSRQ_HOLD_FIRST (68) /* First BUSRQ is really short? */ #define NTSC_BUSRQ_HOLD_NORMAL (108) /* Typical BUSRQs during display */ #define NTSC_BUSRQ_HOLD_EXTRA (38) /* 14th BUSRQ is half-length */ #define NTSC_MUST_BUSAK_TIME (68) /* CPU must ACK a BUSRQ by here */ #define NTSC_BUSRQ_MARGIN (STIC_BUSRQ_HOLD_NORMAL - STIC_MUST_BUSAK_TIME) #define NTSC_STIC_ACCESSIBLE (2900) /* STIC time window during vblank */ #define NTSC_GMEM_ACCESSIBLE (3796) /* GRAM/GROM time window during vbl */ #define NTSC_INITIAL_OFFSET (2782) /* Starting point of first frame. */ /* a stab at PAL timings */ #define PAL_FRAMCLKS (18957) #define PAL_FRAMDIFF (PAL_FRAMCLKS - NTSC_FRAMCLKS) #define PAL_INTRQ_HOLD (2920 + PAL_FRAMDIFF) #define PAL_BUSRQ_HOLD_FIRST (68) /* First BUSRQ is really short? */ #define PAL_BUSRQ_HOLD_NORMAL (108) /* Typical BUSRQs during display */ #define PAL_BUSRQ_HOLD_EXTRA (38) /* 14th BUSRQ is half-length */ #define PAL_MUST_BUSAK_TIME (68) /* CPU must ACK a BUSRQ by here */ #define PAL_BUSRQ_MARGIN (STIC_BUSRQ_HOLD_NORMAL - STIC_MUST_BUSAK_TIME) #define PAL_STIC_ACCESSIBLE (2900 + PAL_FRAMDIFF) /* STIC time window during vblank */ #define PAL_GMEM_ACCESSIBLE (3796 + PAL_FRAMDIFF) /* GRAM/GROM time window during vbl */ #define PAL_INITIAL_OFFSET (2782) /* Starting point of first frame. */ #define STIC_FRAMCLKS (stic->pal ? PAL_FRAMCLKS : NTSC_FRAMCLKS ) #define STIC_INTRQ_HOLD (stic->pal ? PAL_INTRQ_HOLD : NTSC_INTRQ_HOLD ) #define STIC_BUSRQ_HOLD_FIRST (stic->pal ? PAL_BUSRQ_HOLD_FIRST : NTSC_BUSRQ_HOLD_FIRST ) #define STIC_BUSRQ_HOLD_NORMAL (stic->pal ? PAL_BUSRQ_HOLD_NORMAL : NTSC_BUSRQ_HOLD_NORMAL) #define STIC_BUSRQ_HOLD_EXTRA (stic->pal ? PAL_BUSRQ_HOLD_EXTRA : NTSC_BUSRQ_HOLD_EXTRA ) #define STIC_MUST_BUSAK_TIME (stic->pal ? PAL_MUST_BUSAK_TIME : NTSC_MUST_BUSAK_TIME ) #define STIC_BUSRQ_MARGIN (stic->pal ? PAL_BUSRQ_MARGIN : NTSC_BUSRQ_MARGIN ) #define STIC_STIC_ACCESSIBLE (stic->pal ? PAL_STIC_ACCESSIBLE : NTSC_STIC_ACCESSIBLE ) #define STIC_GMEM_ACCESSIBLE (stic->pal ? PAL_GMEM_ACCESSIBLE : NTSC_GMEM_ACCESSIBLE ) #define STIC_INITIAL_OFFSET (stic->pal ? PAL_INITIAL_OFFSET : NTSC_INITIAL_OFFSET ) #endif /* ======================================================================== */ /* This program is free software; you can redistribute it and/or modify */ /* it under the terms of the GNU General Public License as published by */ /* the Free Software Foundation; either version 2 of the License, or */ /* (at your option) any later version. */ /* */ /* This program is distributed in the hope that it will be useful, */ /* but WITHOUT ANY WARRANTY; without even the implied warranty of */ /* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU */ /* General Public License for more details. */ /* */ /* You should have received a copy of the GNU General Public License */ /* along with this program; if not, write to the Free Software */ /* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ /* ======================================================================== */ /* Copyright (c) 1998-2011, Joseph Zbiciak */ /* ======================================================================== */