TOS patch for 1.44MB floppy support ?

[exxos]

In the TOS sources there is stuff like this, but seems to be for ST BOOKs.

Code: Select all

#if STBOOK
hdselect:   tst.w     d0                        /* if != 0 then select HD */
            bne.s     hdselec2
            clr.b     d0                        /* SD mode */
            bra.s     hdselec3
hdselec2:   move.b    #$80,d0                   /* HD mode is bit 7 in PORT A on the sound chip */
hdselec3:   move      sr,d2                     /* save status register */
            move.b    #14,ABSW(psgsel)          /* select port on GI chip */
            move.b    ABSW(psgrd),d1            /* get current bits */
            bclr      #7,d1                     /* clear HD bit */
            or.b      d0,d1                     /* or-in our new bit */
            move.b    #14,ABSW(psgsel)          /* select port on GI chip */
            move.b    d1,ABSW(psgwr)            /* and write 'em back out there */
            move      d2,sr                     /* restore status register */
            rts
#endif

But are there any patches to TOS to add this without having to recompile TOS with that feature enabled ?

[troed]

Well TOS 2.06 can do 1.44MB - as shown by the Mega STE. I think what trips everybody up is how Atari made it "backwards". Instead of the drive telling TOS what the disk is, TOS simply tries one mode and if it receives gibberish it changes the frequency and tries again.

In any case, it works, and is pretty easily emulated (the PAL, to get the register for frequency changes).

[exxos]

That's a point. But now I'm confused as the sources only have the option for ST BOOK. though there is some other stuff in there for 206.. I guess I'll just measure the pin and see if it toggles while accessing the floppy..

[exxos]

Well bit 7 on port A is high on boot then after the logo goes low and stays low regardless of floppy in or not. :shrug: It makes sense by the sources but doesn't make sense as to why / how the MSTE could use HD modes this way :shrug: I assume it uses a wire on the drive to select clocks to the 1772?

EDIT:

Looks to use feedback from the drive on pin 2 of the floppy cable. That GAL feeds the 1772 clock.

Capture.PNG

Port A7, no idea where that's going.

2.PNG

I assume TOS208 might work. Though some links are broken http://www.avtandil.narod.ru/tose.html

[troed]

Pin 2 is an output, not an input (seen from the computer). TOS 2.06 enables HD support if dip switch X (7?) is on, and then it simply tries 8 and 16MHz (through the register decoded by the PAL) and sees which returns valid data from the drive.

https://www.atari-forum.com/viewtopic.p ... 19#p113215

So, emulating the PAL and giving TOS the corresponding dip switch signal is all that's needed to get HD floppy support.

[exxos]

TOS 2.06 enables HD support if dip switch X (7?) is on,

I thought that was just to get HD option on the desktop ? Seems not.

I'm building a new TOS to enable this stuff.. I did have it switching but 4 bombs on desktop :roll:

[atari030]

Troed is right (Atari forum post), it does work for an external drive. I have two, one is an Atari external with an HD mech and the other a cumana type with HD mech. Both work without any modification on the MegaSTE and TT externally as HD. Pop the drive in the housing and go.

[exxos]

So I need to figure out how to enable the HD stuff in TOS somehow.. though I can only see it with ST BOOK stuff. So no idea how it's getting enabled.

[exxos]

Wonder if this is a input not a output as it's enabled but doesn't do anything

Code: Select all

/*
 * TP_41: HD_BIT: HD-Floppy controlling
 *
 * 0: don't change
 * 6: use sound-chip bit 6
 * 7: use sound-chip bit 7
 *
 * TP_42: HD_INVERT: Invert level
 *
 * Control HD-floppy selection via sound-chip bit 6 or 7.
 * If the HD controller expects low-level, also set TP_42 (HD_INVERT) to 1,
 * otherwise high-level will be used.
 * Note: ST-Book uses a low-level on bit 7.
 */
#ifndef TP_41
#define TP_41 7
#endif
#ifndef TP_42
#define TP_42 0
#endif

[exxos]

Does anyone know what register the dip switches are at ?


EDIT:

Code: Select all

cooSTE:     
#if (TOSVERSION >= 0x400)
            moveq     #31,d1                    /* bit 0: PSG, bit 1: 8-bit DMA, 2: CODEC, 3: DSP, 4: Multiplex */
#else
            moveq     #3,d1                     /* bit 0: PSG, bit 1: 8-bit DMA */
#endif
            move.l    #$5F534E44,(a0)+          /* setup SND cookie: Sound hardware */
            btst      #7,d0                     /* DIP switch 7 on? */
            bne.s     cooSND                    /* (punt) */
            bclr      #1,d1                     /* no 8-bit DMA sound */
cooSND:     move.l    d1,(a0)+
            btst      #6,d0                     /* DIP switch 6 on? */
            bne.s     cooFDC                    /* (punt - no HD floppy) */
            move.b    #8,dsb                    /* select HD density for drive A */
            move.l    #'_FDC',(a0)+             /* setup FDC cookie: Floppy disk controller */
            move.l    #$01415443,(a0)+          /* 'ATC' | (1 << 24) */
cooFDC:     move.l    #$5F465055,(a0)+          /* Setup FPU cookie: Type of the FPU */
            moveq     #0,d7                     /* 0 = no FPU */
            suba.w    #$24,sp
            move.l    (_lineftrap).w,(sp)
            move.l    (_coprovio).w,4(sp)
            move.l    #cooFPU,(_lineftrap).w
            move.l    #cooFPU,(_coprovio).w
            lea       8(sp),a1
            movea.w   #_cpunordered,a2
            move.l    #cooFPU2,d0
            move.l    (a2),(a1)+
            move.l    d0,(a2)+
            move.l    (a2),(a1)+
            move.l    d0,(a2)+