---

From: pegram@uvm-gen.UUCP (Robert B. Pegram) Newsgroups: comp.sys.atari.st.tech Subject: How to upgrade your ST floppies to 1.44Meg 3.5" drives Date: 18 Jul 90 16:14:16 GMT Sender: nobody@uvm-gen.UUCP Organization: EMBA Computer Facility, Univ. of Vermont, Burlington. Tried to post this yesterday from GnuEmacs - no go. Here it is, Hartmut Semken(AKA hase)'s 1.44 meg Upgrade for Atari STs and Megas. This is a compilation of several postings, edited by Bob Pegram, my comments are indicated by [..text..] <- RBPIII. I have yet to do the upgrade myself (lazy 8-), but it seems workable. From the TT rumor about no HD floppy for now, it would seem that Atari is doing the same thing, only with a new (not yet fully available) floppy controller from Western Digital that *is rated* to handle the higher clock input that is necessary. Thus, in the future, this upgrade may become a more reliable and simple chip replacement. Enjoy, Bob Pegram originally From: hase@hase_1.UUCP (Hartmut Semken) original Subject: Re: Floppy drive 1.44 meg woes! original Date: 11 Feb 90 09:55:00 GMT References: <9002030029.AA23185@jade.berkeley.edu> <2103@ultb.isc.rit.edu> Organization: h.a.s.e., Berlin, West Germany clf3678@ultb.isc.rit.edu (C.L. Freemesser) writes: Reply-To: hase@netmbx.UUCP (Hartmut Semken) Organization: netmbx Public Access Unix, Berlin, West Germany Lines: 28 Posted: Sat Nov 25 17:57:46 1989 >> I'm having a few problems hooking up my 1.44 meg teac. I was wondering > From what I know, you can't use HD on the ST. The controller chip >can't handle it. Just be glad it works in 720k mode. :^) Well, you can, if you hack the hardware. Here we go again: The trick is to double the clock frequency of the controller chip, so it will talk twice as fast to the drive: the bit stream has "high-density" format. A clock of 16 MHz is well beyond specification (the WD1772 is rated to run at up to 10 MHz), but it will work most of the time. The hack consists of two parts: hardware and software and works with ( [3.5 inch] <- RBPIII ) high density drives only! [The reason being that the drive must auto-sense the HD disk when it is inserted and change its RPMs up accordingly. 5.25 (1.2Meg) drives do *not* do this! Neither do all HD 3.5" floppies (notably the ones on true blue PS 2 s). ] <- RBPIII Now: the hardware. The clock pin of the WD1772 is pin 18. It is normally hooked to the 8 MHz clock. Cut this pin and connect it to the output of a simple circuit. feed the two inputs of this simple circuit with 8 MHz and 16 MHz clocks (16 MHz can be gotten at SHIFTER pin 39). The "simple circuit" mentioned above could be a simple, manual switch. Now You are able to select two clock frequencies and therfore two "modes" for the controller chip: double density and high density. The simple circuit could also be a multiplexer (74LS157, I think) controlled by the "I detected a HD-disk in me"-output of the floppy drive (the TEAC FD 235 HFN provides this outout on pin 2 if a jumper is set; the 235 HFN has a second jumper that enables internal detection of HD disks: this must be set, too). With the MUX, a disk inserted will select the appropriate mode of operation automatically. Do not worry about two drives in different modes: when copying from one drive to the other, the clock rate will be switched once to twice a second. This will not trouble the controller (remember the clock to be in the range of Megahertz...). If you want to connect one HD drive and one DD drive, you'll need two more TTL gates (one 74LS00 will do) to make sure, the controller is in DD mode for the DD only drive: invert the HD-detected-output (it is LOW for DD before, HIGH for DD behind the inverter) and feed it into a NAND gate together with drive select for the DD drive. Let a HIGH output of the NAND gate select DD-clock (8 MHz). Now "not-HD-detected OR DD-drive-select" will select DD mode, right? With two HD drives, there is no problem at all :-) [except for the High Density floppy boot problem, discussed below. You have to set the step rate from the boot sector.] <- RBPIII Now for the software: The controller uses its clock as base for all timings. The pulse width and time between pulses for the step line are controller controlled. ^^^^^^^^^ [WD 1772] <- RBPIII To make it short: with the doubled clock the controller will try to make the head step twice as fast: he will send a step pulse every 1.5 milliseconds if set to 3 milliseconds (which is TOS standard). Just set the step rate to 6 milliseconds to make the controller step 3 milliseconds in HD mode (well, the 6 milliseconds steps in DD mode will slow down floppy operation a bit, but not that much. Not stepping, [but] reading and writing takes the time!). How to set the step rate? Well, there is a documented TOS variable for the step rate at 0x440 called seekrate. The step rate in this variable will be used by the BIOS after a call of the routine, pointed to by "hdv_init" (the hdv_init routine seems to initialize the BIOS parameter blocks for the floppies). The pointer to hdv_init can be found at 0x46A (this is a supported TOS variable, too). Look at the MWC-Assembler source below. [More information on the step rate from another posting - between the curly braces below] <- RBPIII { In article <1346@uvm-gen.UUCP> pegram@uvm-gen.UUCP (pegram r) writes: > >Rats! I looked up the possible seek rates last night, 6 msec is as slow >as she goes. Hmm, TOS will step at 6,12,2,3 msec (with rate codes 0,1,2,3). Setting the controller to 6 msec and doubling the clock works for almost all 3.5 inch HD drives. [I wanted to know if you could still use a (360 K) 5.25 drive, which needs a true 6 msec step rate. This was when no WD 1772 clock switching (between 8 and 16 Mhz) was contemplated. If your 1772 works this fast, you can forget the switch, or use a properly buffered manual switch for those rare occasions when it's necessary. "Properly buffered" you ask? See any of the usual designs that eliminate switch bounce - Radio Shack's pamphlets on digital electronics have the circuits needed. The 74LS00 mentioned above will work nicely as the debouncer and "glue". You still want that Multiplexer and you send in the debounced 16Mhz ("On" or "TRUE") and 8Mhz (The inverted "FALSE" or "OFF") outputs from the manual switch to select the clocks. That is just a design off the top of my head, which needs to be improved. Please do post a better one if you come up with one, I can think of a one chip (the LS00) solution if clock skew to the WD1772 is unimportant (as in 180 degrees out of phase 8-). The reason I mention it is because, I believe that the problem mentioned at the beginning of the original posting was due to either an incorrect jumper setting on the drive, or a noise problem in the ST, having the clocks going all over the ST to the switch, is not a good idea at all! You don't have to worry about driving more capacitance with such free standing wires, but you do have to think about the effect of having some new high frequency antennas inside your ST!] <- RBPIII >It would also be hard to boot from a floppy with this >mod (double - 16Mhz - clock for 1772 + formatter + "6"msec seek rate). >Do you have to have a seek rate setting boot sector on every boot >floppy and would that idea even work? Sure, that should work, since no steps schould be necessary to read the boot sector. I boot from harddisk... [Me too, but some utilities (DC formatter at least) can format disks with boot sectors that can reset the step rate on boot up. Game disks could be similarly hacked to work with the new drive.] <- RBPIII If the HD-floppy does not work after modifying the ST, the step pulse width is a probable cause. In that case, use an edge-triggered monoflop to "resize" the pulse. ^^^^^^^^ [hase means a monostable or "one-shot" available in TTL or with the "555" timer chip.] <- RBPIII } The second thing is to get a formatter that will format 18 sectors per track. HYPERFORMAT by Claus Brodt is such a thing, but a simple formatter hacked from the example in the Mark Williams C Lexicon did the same. It's included below. For help try to write to hase@hase_1.mbx.sub.org, but it'll probably bounce; our mail service is fading fast... [Check if hase's current address is the same, he does show up on c.s.a.s] <- RBPIII I'll try to reply to anything, I finally get. hase ------- cut for seek6.s ----------- /module name seek6 .shri .globl main_ main_: clr.l-(sp) move.w$0x20,-(sp) trap$1 addq.l$6,a7 move.ld0,_save_ssp move.w$0,0x440/ 0 => 6 ms lea0x46a,a0 move.l(a0),d0 movea.ld0,a0 jsr(a0) move.l_save_ssp,-(sp) move.w$0x20,-(sp) trap$1 addq.l$6,a7 .even _save_ssp: .blkl1 / seek rate codes are 0,1,2,3 for 6,12,2,3 milliseconds Sets seek rate to 6 Milliseconds for *all* drives (with *any* TOS version; tested on Rainbow TOS (1.4), BLiTTER TOS (1.2) and TOS 1.0): ------------ cut for formath.c ------------- /* formath.c Formatter fuer High Density Disketten */ /* nur fuer angepasste Hardware! Floppycontroller und Laufwerk */ /* muessen High-Density tauglich sein! */ /* Hartmut Semken, Lupsteiner Weg 67 1000 Berlin 37 */ /* hase@hase_1.mbx.sub.org or hase@netmbx.mbx.sub.org */ /* 03-SEP-89 */ #include #include #include #define SLEEPTIME 1/* 1: Zeitschleife, 0: Taste */ #define BLANK (0xE5E5) #define MAGIC (0x87654321L) #define BUFSIZE (20*1024) /* Platz fuer mehr als 18 Sektoren... */ #define DEVICE 0/* 0 = Floppy A, 1 = Floppy B*/ #define SIDES 2/* je */ #define SECTORS 18/* nach*/ #define TRACKS 80/*Belieben*/ #define TOTSEC (TRACKS * SIDES * SECTORS) extern int errno; main(){ int track; int side; int status; short *bf; register char reply; short *middle; char buffer[512]; printf("\033E\n"); printf("Public Domain High Density Mini Formatter\n"); printf("von H. Semken\nDer Autor garantiert in keiner Weise fr die Funktion\nDi eses Programmes.\nBenutzung auf eigene Gefahr.\n"); printf("\n\n\n"); printf("\007\033pFormatiere Diskette in Drive %c\033q\n%d Seiten\n%d Sektoren p ro Spur\n%d Spuren\n\n", (65+DEVICE), SIDES, SECTORS, TRACKS); printf("Wirklich formatieren? "); fflush(stdout); if ((reply = Crawcin()) != 'y' && reply != 'Y' && reply != 'j' && reply != 'J') { printf("Nein. Floppy nicht formatiert.\n"); sleep(1); Pterm0(); } printf("Ja.\n"); printf("Diskette einlegen; Taste drcken..."); fflush(stdout); Crawcin(); printf("\n"); bf = malloc(BUFSIZE); for (track = TRACKS-1; track >= 0; track--) { for (side = 0; side < SIDES; side++) { printf("Formatiere Spur %d, Seite %d", track, side); fflush(stdout); status = Flopfmt(bf, 0L, DEVICE, SECTORS, track, side, 1, MAGIC, BLANK); if (status) { middle = bf; printf("\t%d\n", status); while (*middle) { printf("\tDefekter Sektor %d\n", *middle++); } } else { printf("\tokay\r"); } } } printf("\n\nAlle Spuren formatiert\n"); printf("Initialisiere Directory\n"); for (track = 0; track < (BUFSIZE>>1); bf[track++] = 0); for (track = 0; track < 2;track++) { for (side = 0; side < SIDES; side++){ if (status = Flopwr(bf, 0L, DEVICE, 1, track, side, SECTORS)) { errno = -status; perror("Write Error"); } } } Protobt(buffer, (long)Random(),3,0); /* Prototyp Bootsector fr * 80 * 2 * 9 Sektoren */ /* Prototyp Bootsektor fr das neue Format anpassen */ /* Bytes 19 und 20 enthalten die Sektoren pro Disk */ /* unteres Byte von TOTSEC */ buffer[19] = (char)(((TOTSEC>>8)<<8)^TOTSEC); /* oberes Byte von TOTSEC; es lebe das Intel int-Format */ buffer[20] = (char)(TOTSEC>>8); buffer[24] = (char)SECTORS; /* Sektoren pro Spur */ status = Flopwr(buffer, 0L, DEVICE, 1, 0, 0, 1); if (status) { errno = -status; perror("Write Error (Bootsector)"); } status = Flopver(buffer, 0L, DEVICE, 1, 0, 0, 1); if (status) { errno = -status; perror("Verify Error (Bootsector)"); } printf("Diskette in Laufwerk %c formatiert\n", (65+DEVICE)); sleep(1); Pterm0(); } sleep(seconds) int seconds; #if SLEEPTIME { clock_t t; for(t = clock();clock() < (t + CLK_TCK*seconds);); } #else { printf("Taste druecken\n"); fflush(stdout); Crawcin(); } #endif -- original idea and post by: >Hartmut Semken, Lupsteiner Weg 67, 1000 Berlin 37 hase@hase_1.UUCP >Dennis had stepped up into the top seat whet its founder had died of a >lethal overdose of brick wall, taken while under the influence of a >Ferrari and a bottle of tequila. (Douglas Adams; the long dark teatime...) Additions by: Bob Pegram Internet: pegram@griffin.uvm.edu UUCP: you figure it out! Physical Mail: R. Pegram, R.R. #2, Box 2843, Green St., Vergennes, Vt. 05491, U.S.A. Home Tel: (in N.A., add appropriate codes if elsewhere) (802) 877 0018

---

The views and opinions stated within this web page are those of the author or authors which wrote them and may not reflect the views and opinions of the ISP or account user which hosts the web page. The opinions may or may not be those of the Chairman of The Skeptic Tank.

Return to The Skeptic Tank's main Index page.

E-Mail Fredric L. Rice / The Skeptic Tank