billy@phoenix.pub.uu.oz.au (Jeff Coleman) (02/28/91)
[i've posted this for james] A few months ago, someone posted a do-it-yourself hardware mod to enable the St to use 1.44 meg drives. Could the author kindly repost this or anybody else with the knowledge please make it known ? (Im aware that pre made kits exists to do this already but Id prefer to do it myself) Reply via email or news... ----------------------------------------------------------------------- James Hall. s883334@minyos.xx.rmit.oz.au OR mith@arda.pub.uu.oz.au -----------------------------------------------------------------------
hase@netmbx.UUCP (Hartmut Semken) (03/03/91)
billy@phoenix.pub.uu.oz.au (Jeff Coleman) writes: > A few months ago, someone posted a do-it-yourself hardware mod to enable >the St to use 1.44 meg drives. Could the author kindly repost this or >anybody else with the knowledge please make it known ? >(Im aware that pre made kits exists to do this already but Id prefer to do > it myself) It is pretty easy. The trick is to double the clock of the WD1772 floppy controller chip to get HD bit streams. The regular clock is 8 MHz and 16 MHz can be get from the shifters 16 MHz output (see the Abacus Internals book for the pinouts; if the Abacus book is the translation of the german Data Becker book, it should have all the pinouts). You could use a simple switch to changs the clock, but I found a Multiplexer (1/2 74LS157) controlled by the "HD disk in drive" output of the Teac FD 235 HF more elegant... For the 5.25 inch Teac FD 55 GF I use a switch... The problem ist, that the floppy controller will step twice as fast with the doubled clock; that will be too fast for any drive mechnism. So You'll have to set the step rate to 6 milliseconds to make the controller step at 3 milliseconds in HD mode (6 ms in DD mode does not hurt performance too much, so You can leave the Controller at 6 ms all the time). Setting the seek rate is easy: write the appropriate seek rate code (6 for 6 ms, I recall) to the seek rate system variable (is it at 0x4c0 ? Check it...) and then jump to the "hdv_init" routine (the adress of that routine is found in the system variables, too.) hdv_init will make new BIOS parameter blocks for both drives with the new seek rate. This works with any version of TOS, cause it uses documented system variables and system calls only, but it will affect the seek rate for both drives. Now, all You need is a formatter program that will format 18 (or up to 20) sectors per track (or 15/16 sectors per track HD 5.25 inch). A simple formatter using the XBIOS format routine is in the Mark Williams C Compiler docs. I hacked it to use a track buffer twice as large and it formatted HD disks with 18 sectors... Thats all! hase -- Hartmut Semken, Lupsteiner Weg 67, 1000 Berlin 37 hase@netmbx.UUCP Hi! (Zaphod Beeblebrox)
Roger.Sheppard@bbs.actrix.gen.nz (03/06/91)
Distribution:world In article <1991Feb28.085205.28239@phoenix.pub.uu.oz.au> billy@phoenix.pub.uu.oz.au (Jeff Coleman) writes: > [i've posted this for james] > > A few months ago, someone posted a do-it-yourself hardware mod to enable > the St to use 1.44 meg drives. Could the author kindly repost this or > anybody else with the knowledge please make it known ? > (Im aware that pre made kits exists to do this already but Id prefer to do > it myself) > > Reply via email or news... > ----------------------------------------------------------------------- > James Hall. > s883334@minyos.xx.rmit.oz.au OR mith@arda.pub.uu.oz.au > ----------------------------------------------------------------------- Well the USA kit changes the controller IC. to a WD 279X, this is the Proper way, but don't know how they get over the Motor ON command, The other way is the one that the Germans came out with is to Change the Clock to the WD 1770 controller IC, but this can be hit or miss as the IC is not ment to run with a 16 Meg HZ clock, also you have to have a switch to change the clock back, or the sence line from the drive to control the clock...I would like to try this but I will have to borrow a drive first no piont in buying a drive if it does not work !!! -- Roger W. Sheppard 85 Donovan Rd, Kapiti New Zealand...
luoto@cs.Helsinki.FI (Markku Luoto) (03/08/91)
where can you get this US-kit ??? has anybody had any experiences....(good or bad) ---> and what is the aprox. price ??? thank's >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< >>>>>> " I'm completely operational & all my cicuits are functioning <<<<<< >>>>>> correctly...correc...corr...co...-! " : HAl9000 <<<<<< >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
adamd@rhi.hi.is (Adam David) (03/13/91)
In <1991Mar06.123439.20676@actrix.gen.nz> Roger.Sheppard@bbs.actrix.gen.nz writes: >The other way is the one that the Germans came out with is to Change the >Clock to the WD 1770 controller IC, but this can be hit or miss as the >IC is not ment to run with a 16 Meg HZ clock, The WD1772 controller has to be the more recent type for it to work properly. All recent ST's should have the right chip. The suffix on the older chip is -01 and on the newer one is -02. I think the date-stamps are 1985 and 1987. The simplest way is to let the density sense line select the clock speed. The clock to the controller should be deglitched during the speed change. If you want to format DD disks to HD (doubtful practice) then a little more circuitry is required, probably involving the sound chip. It would be nice to change the step rate for the drives to suit the disk each time a disk is changed. I don't have it up and running yet, so I can't post the details. If no-one beats me to it I'll get it done sometime. Meanwhiles, could someone point out which pins carry these signals: a) disk-in-drive b) density-sense c) .....anything else not on older DD drives? oh, and while I'm at it: Does anyone know whether the WD1772 can handle 1024-byte sectors? If so then it should be possible to format 1848k onto a HD disk. -- Adam David. adamd@rhi.hi.is
hase@netmbx.UUCP (Hartmut Semken) (03/13/91)
adamd@rhi.hi.is (Adam David) writes: >In <1991Mar06.123439.20676@actrix.gen.nz> Roger.Sheppard@bbs.actrix.gen.nz writes: >It would be nice to change the step rate for the drives to suit the disk each >time a disk is changed. This cannot be done in a way, that will work on all versions of TOS, cause the location of the drive parameter block in RAM varies with the TOS version. If You want to use documented system calls only, You ll have to change the step rate once and for all. >a) disk-in-drive >b) density-sense >c) .....anything else not on older DD drives? depends on drive. There is no standard. Teac FD235HF carry the "DD-disk-in-drive" (active low) on pin 2 if the appropriate jumper on the drive is set. You must also set the HD jumper for the drive to detect HD floppies and reduce write current whe DD disks are inserted. >oh, and while I'm at it: >Does anyone know whether the WD1772 can handle 1024-byte sectors? >If so then it should be possible to format 1848k onto a HD disk. This can be done in software. The WD1772 will read and write 256, 512 and 1024 byte sectors. TOS will only work with 512 byte sectors. It is possible and pretty safe to format 10 sectors per track with DD floppies, and so is 20 sectors per track with HD drives and media. hase -- Hartmut Semken, Lupsteiner Weg 67, 1000 Berlin 37 hase@netmbx.UUCP Hi! (Zaphod Beeblebrox)
vsnyder@jato.jpl.nasa.gov (Van Snyder) (03/14/91)
In article <2083@netmbx.UUCP> hase@netmbx.UUCP (Hartmut Semken) writes: >adamd@rhi.hi.is (Adam David) writes: > >>In <1991Mar06.123439.20676@actrix.gen.nz> Roger.Sheppard@bbs.actrix.gen.nz writes: >>It would be nice to change the step rate for the drives to suit the disk each >>time a disk is changed. > >This cannot be done in a way, that will work on all versions of TOS, >cause the location of the drive parameter block in RAM varies with the >TOS version. The Rainbow TOS developers' notes had a description of how to set the step rate in all versions of TOS. E-mail me if you're interested, and if there's interest I'll post it. -- vsnyder@jato.Jpl.Nasa.Gov ames!elroy!jato!vsnyder vsnyder@jato.uucp
Roger.Sheppard@bbs.actrix.gen.nz (03/15/91)
Distribution:world In article <2886@krafla.rhi.hi.is> adamd@rhi.hi.is (Adam David) writes: > In <1991Mar06.123439.20676@actrix.gen.nz> Roger.Sheppard@bbs.actrix.gen.nz writes: > > The WD1772 controller has to be the more recent type for it to work properly. > All recent ST's should have the right chip. The suffix on the older chip is -01 > and on the newer one is -02. I think the date-stamps are 1985 and 1987. The > simplest way is to let the density sense line select the clock speed. The clock > to the controller should be deglitched during the speed change. If you want to > format DD disks to HD (doubtful practice) then a little more circuitry is > required, probably involving the sound chip. > It would be nice to change the step rate for the drives to suit the disk each > time a disk is changed. > > Does anyone know whether the WD1772 can handle 1024-byte sectors? > If so then it should be possible to format 1848k onto a HD disk. > -- > Adam David. > adamd@rhi.hi.is Yes it can, the Sector Length byte is 03 for 1024, Note, I think the Germans use the 22 sector format to get this size, but you will have problems booting with a 1024 sector, the TOS does not suport that size, But have seen some use od a Driver and a Mix of 512 and 1024 sector size. From what I now, the -02 Part No. for the WD 1772 was for the Atari none standard step rate, but I could be wrong. Note , Atari does not use the WD1772-01 step rates of 2/3/5/6ms, but use 2/3/6/12 , this I think is why the Part No. is WD1772-02 -- Roger W. Sheppard 85 Donovan Rd, Kapiti New Zealand...
Roger.Sheppard@bbs.actrix.gen.nz (03/15/91)
Distribution:world In article <2083@netmbx.UUCP> hase@netmbx.UUCP (Hartmut Semken) writes: > adamd@rhi.hi.is (Adam David) writes: > > >In <1991Mar06.123439.20676@actrix.gen.nz> Roger.Sheppard@bbs.actrix.gen.nz writes: > >It would be nice to change the step rate f^^^^^^^^^^^^^^or the drives to suit the disk each time a disk is changed. > Please Note. this is not my posting, so Please don't quote me as the Author of this Article. This was from a Folowup Article to mine... > hase > -- > Hartmut Semken, Lupsteiner Weg 67, 1000 Berlin 37 hase@netmbx.UUCP > Hi! (Zaphod Beeblebrox) -- Roger W. Sheppard 85 Donovan Rd, Kapiti New Zealand...
adamd@rhi.hi.is (Adam David) (03/16/91)
In <2083@netmbx.UUCP> hase@netmbx.UUCP (Hartmut Semken) writes: >adamd@rhi.hi.is (Adam David) writes: >>It would be nice to change the step rate for the drives to suit the disk each >>time a disk is changed. >This cannot be done in a way, that will work on all versions of TOS, >cause the location of the drive parameter block in RAM varies with the >TOS version. Surely there are sensible ways of finding where these are located, if this is what's needed. Since it is possible to have separate steprates for drives A: and B: then there must be a reliable method for changing the steprate on individual drives. Install the routine into the mediach vector, it's almost there now. >>Does anyone know whether the WD1772 can handle 1024-byte sectors? >This can be done in software. The WD1772 will read and write 256, 512 >and 1024 byte sectors. TOS will only work with 512 byte sectors. Presumably the BIOS handles various sector sizes by using the BPB. Is TOS really limited to using standard sectors? What about hard disks which also have larger sectors? (or do they all use 512-byte sectors with more sectors per cluster?). In the worst case a few routines will need to be patched or rewritten if there are indeed incompatibilities. Besides cramming more data onto the disks, being able to use 1024-byte sectors gives access to disks written on other systems which use this format. -- Adam David. (adamd@rhi.hi.is)