cs4w+@andrew.cmu.edu (Charles William Swiger) (11/03/90)
Anybody have a detailed description of the $C0Ex range of addresses?
(Which are the registers that control a 5.25" drive at the lowest level
possible.)
I've disassembled DOS 3.3 RWTS, the $C600 boot code, parts of ProDOS,
etc and the function of some locations are obvious, but others aren't.
Thanks.
-- Charles William Swiger
cs4w+@andrew.cmu.eduMQUINN%UTCVM@PUCC.PRINCETON.EDU (11/03/90)
On Fri, 2 Nov 90 17:12:29 GMT Charles William Swiger said: >Anybody have a detailed description of the $C0Ex range of addresses? >(Which are the registers that control a 5.25" drive at the lowest level >possible.) > >I've disassembled DOS 3.3 RWTS, the $C600 boot code, parts of ProDOS, >etc and the function of some locations are obvious, but others aren't. >Thanks. > > > >-- Charles William Swiger > cs4w+@andrew.cmu.edu ADDRESS LABEL DESCRIPTION ----------------------------------------------------------------- $C080 PHASEOFF Stepper motor phase 0 off. $C081 PHASEON STEPPER MOTOR PHASE 0 ON. $C082 PHASE1OFF STEPPER MOTOR PHASE 1 OFF. $C083 PHASE1ON STEPPER MOTOR PHASE 1 ON. $C084 PHASE2OFF { } $C085 PHASE2ON { YOU CAN FIGURE } $C086 PHASE3OFF { OUT THESE } $C087 PHASE3ON { } $C088 MOTOROFF TURN OFF MOTOR. $C089 MOTORON TURN MOTOR ON. $C08A DRVOEN ENGAGE DRIVE 1 $C08B DRV1EN ENGANE DRIVE 2 $C08C Q6L STROBE DATA LATCH FOR I/O $C08D Q6H LOAD DATA LATCH. $C08E Q7L PREPARE LATCH FOR INPUT. $C08F Q7H PREPARE LATCH FOR OUTPUT. Q7L WITH Q6L = READ Q7L W/ Q6H = SENSE WRITE PROTECT Q7H W/ Q6L = WRITE Q7H W/ Q6H = LOAD WRITE LATCH --------------------------- You need to at $x0 to $C08n where x is the slot number. --------------------------- Addresses $C080 through $C087 are for moving the drive arm. The arm moves in QUARTER tracks so each access to one 'SET' of those addresses moves the arm 1/4 a track: LDA $C0E0 LDA $C0E1 will move the arm a quarter track ($C0E0 for slot 6). To move a whole track, cycle through the whole set of stepper motor phases: LDA $C0E1 LDA $C0E0 LDA $C0E3 LDA $C0E2 . . LDA $C0E7 LDA $C0E6 The first access to one of these addressess starts up the arm and the other stops it. To move the arm in the opposite direction, cycle through these the other way (the PHASEON of each set always comes first). You must start the drive up before (or turn it on) by accessing $C0E9 first. Immediately after starting it up, you must tell it WHICH drive: LDA $C0EA ----> access drive 1 LDA $C0EB ----> access drive 2 You might want to set it to READ first, immediately after starting up the drive. I can't remember how to do this, you could probably figure it out with the Q6L - Q7H things and a scratch disk. You can also check to see if the disk is write protected with those four addresses, although I can't recall how right now. The data latch out $C0EF is the address you write to to actually write a byte to disk, but you must have enabled write mode first somehow using Q6 and Q7 H&L. To READ from the disk, read from address $C0EE, but you must first anable reading AND allow the drive time to get up to speed. For those of you wondering why ProDOS anly allows two drives per slot, it's probably because there are only two addresses per slot ($C0xA & $C0xB) to determine which drive to access. I got this info from "Beneath Apple DOS"... The most useful book I've ever read to this date. I imagine that "Beneath Apple ProDOS" would be even better. Anyone got a copy they want to sell? By the way, those books are from Quality Software If there is anyone that hasn't read either of these books, I HIGHLY recommend them! "Beneath Apple DOS" covers virtually every conceivable thing you would want to know about DOS 3.3, including copy protection schemes and how to break them and even how to make your own (It's easier to make your own than to crack one :) Even though these books are outdated (well, the ProDOS one may not be), they're still EXTREMELY informative on Disk Operating Systems in General. I find mysel f explaining how DOS's work to sceniors in computer science and even to computer science proffessors just from the stuff I learned from the DOS 3.3 book! ____________________________________________________________________ | | | | This is your brain... | BITNET-- mquinn@utcvm | | This is your brain on drugs... | pro-line: | | This is your brain on frog licking.| mquinn@pro-gsplus.cts.com | |____________________________________|_______________________________|
parkern@jacobs.CS.ORST.EDU (Neil Parker) (11/08/90)
In article <9011030453.AA02428@apple.com> MQUINN%UTCVM@PUCC.PRINCETON.EDU writes: >On Fri, 2 Nov 90 17:12:29 GMT Charles William Swiger said: >>Anybody have a detailed description of the $C0Ex range of addresses? >>(Which are the registers that control a 5.25" drive at the lowest level >>possible.) >> >>I've disassembled DOS 3.3 RWTS, the $C600 boot code, parts of ProDOS, >>etc and the function of some locations are obvious, but others aren't. >>Thanks. >> >> >> >>-- Charles William Swiger >> cs4w+@andrew.cmu.edu > >ADDRESS LABEL DESCRIPTION >----------------------------------------------------------------- >$C080 PHASEOFF Stepper motor phase 0 off. >$C081 PHASEON STEPPER MOTOR PHASE 0 ON. >$C082 PHASE1OFF STEPPER MOTOR PHASE 1 OFF. >$C083 PHASE1ON STEPPER MOTOR PHASE 1 ON. >$C084 PHASE2OFF { } >$C085 PHASE2ON { YOU CAN FIGURE } >$C086 PHASE3OFF { OUT THESE } >$C087 PHASE3ON { } >$C088 MOTOROFF TURN OFF MOTOR. >$C089 MOTORON TURN MOTOR ON. >$C08A DRVOEN ENGAGE DRIVE 1 >$C08B DRV1EN ENGANE DRIVE 2 >$C08C Q6L STROBE DATA LATCH FOR I/O >$C08D Q6H LOAD DATA LATCH. >$C08E Q7L PREPARE LATCH FOR INPUT. >$C08F Q7H PREPARE LATCH FOR OUTPUT. > > Q7L WITH Q6L = READ > Q7L W/ Q6H = SENSE WRITE PROTECT > Q7H W/ Q6L = WRITE > Q7H W/ Q6H = LOAD WRITE LATCH So far, so good. The explanation which followed, however, might be a bit misleading. The following is taken from "Beneath Apple DOS" and "Beneath Apple ProDOS", which I have sitting in front of me as I type. I am also using "Use of the Disk II Interface Card Through Your Own Software" by John Uhley, from the April 1983 issue of "Apple Orchard" (which goes into considerably more detail about stepping tracks than "Beneath Apple *DOS"). Basically, each track (and half-track) may be considered to be "under" one of the four phases of the stepper motor. Track Phase ---- ----- 0 0 0.5 1 1 2 1.5 3 2 0 2.5 1 3 2 3.5 3 etc.. To figure the phase for a given (half-)track, multiply the track number by 2, and keep only the two low-order bits. Stepping from one track to another is simply a matter of stepping one track at a time from the original track to the destination track. Thus, to step inward from track A to track B, first step to (half-)track A+0.5, then to (half-)track A+1, and so on, until you arrive at track B. Likewise, to step outward from track B to track A, first step to (half-)track B-0.5, then to B-1, and so on until you arrive at track A. An individual step (which must from the original half-track to one if its immediatly neighboring half-tracks) is accomplished by turning on the appropriate phase, waiting, and turning off the phase. An appropriate wait may be obtained by loading the accumulator with #$56 and doing a JSR to the Monitor's WAIT routine ($FCA8). (DOS and ProDOS are able to obtain improved speed by taking into account the fact that once the head is moving, it takes less time to make subsequent steps.) Note that this scheme requires DOS to keep track of which track it's on--there's no way to ask the drive where the head is. If the current track number is unknown, the head must be "recalibrated" by assuming that we're currently at track 35 (or beyond), and then seeking to track 0 (this is what causes that awful GRRRRRINDing sound when you boot a 5.25" disk). Assuming that the disk motor is on, the following code (lifted from the Apple Orchard article) will step from CURTRK to DESTRK on the disk drive whose slot number (*16) is stored in SLOT: MAINLOOP LDA CURTRK CMP DESTRK BEQ ALLDONE BCC MOVEUP BCS MOVEDOWN ; ; MOVE DOWN TO LAST PHASE ; MOVEDOWN DEC CURTRK JMP DOWORK ; ; MOVE UP TO NEXT PHASE ; MOVEUP INC CURTRK ; ; COMPUTE PHASE NUMBER ; FROM THE "NEW" CURTRK ; DOWORK LDA CURTRK AND #$03 ASL ; ; GET INDEXING FOR CUR SLOT# ; ORA SLOT TAY ; ; TURN ON PHASE TO MOVE & ; WAIT FOR PHYSICAL ACTION ; LDA $C081,Y LDA #$56 JSR $FCA8 ; ; TURN OFF PHASE (ALWAYS) % ; LOOP BACK TO CHECK ON NEW ; CURTRK-DESTRK RELATIONSHIP ; LDA $C080,Y JMP MAINLOOP ; ; ALL DONE... QUIT ; ALLDONE (Your code continues here) Most other drive operations are simpler than stepping. Turning on the drive: LDX SLOT LDA $C089,X Once the drive is on, you have to wait for the motor to come up to speed. The Apple Orchard article uses the following code for the delay: LDA #$EF STA WAIT LDA #$D8 STA WAIT+1 MWAITA LDY #$12 MWAITB DEY BNE MWAITB INC WAIT BNE MWAITA INC WAIT+1 BNE MWAITA where WAIT is a location on zero-page. Again, DOS is able to decrease the delay by some clever timing. Selecting drive 1: LDX SLOT LDA $C08A,X Selecting drive 2: LDX SLOT LDA $C08B,X Sensing write-protect: LDX SLOT LDA $C08D,X LDA $C08E,X BMI PROTECTED Setting READ mode (necessary for reading): LDX SLOT LDA $C08E,X Reading a byte (after selecting READ mode): LDX SLOT READLP LDA $C08C,X BPL READLP Writing data: First, sense the write-protect status. Then, LDX SLOT LDA DATA1 STA $C08F,X ORA $C08C,X (wait) LDA DATA2 STA $C08D,X ORA $C08C,X (wait) LDA DATA3 STA $C08D,X ORA $C08C,X (etc...) The wait time must be such that the accesses to $C08C come EXACTLY 32 machine cycles apart. Note also that the first data byte is written differently than subsequent bytes--the access to $C08F in necessary to set WRITE mode. After all data is written, you should access $C08E to select READ mode, in order to prevent data from being erased. At one point (in the disk formatting code), DOS 3.3 uses code like this to write data at 32-cycle intervals: LDA #$D5 (2 cycles) JSR WRITE9 (6) LDA #$AA (2) JSR WRITE9 (6) . . . WRITE9 CLC (2) WRITE7 PHA (3) PLA (4) WRITE STA $C08D,X (5) ORA $C08C,X (4) RTS (6) There is a LOT more to know about disk formatting than what is covered in this post. If you can find a copy of "Beneath Apple DOS", buy it--it will tell you just about everything there is to know about the format of a 5.25" disk. "Beneath Apple ProDOS" has a similar, but somewhat abbreviated discussion. >| | | >| This is your brain... | BITNET-- mquinn@utcvm | >| This is your brain on drugs... | pro-line: | >| This is your brain on frog licking.| mquinn@pro-gsplus.cts.com | >|____________________________________|_______________________________| - Neil Parker -- Neil Parker No cute ASCII art...no cute quote...no cute parkern@jacobs.cs.orst.edu disclaimer...no deposit, no return... parker@corona.uoregon.edu (This space intentionally left blank: )
nparker@cie.uoregon.edu (Neil Parker) (11/09/90)
In article <1990Nov08.105414.22053@scion.CS.ORST.EDU> parkern@jacobs.cs.orst.edu (Neil Parker) writes: >[lotsa stuff deleted] >Assuming that the disk motor is on, the following code (lifted from the >Apple Orchard article) will step from CURTRK to DESTRK on the disk drive >whose slot number (*16) is stored in SLOT: I realized after I posted this routine that I failed to state that CURTRK and DESTRK should contain HALF-TRACK numbers, not TRACK numbers. To obtain the half-track number, multiply the track number by two. For example, LDA CURRENT_TRACK ASL STA CURTRK LDA DEST_TRACK ASL STA DESTRK I apologize for any confusion caused by this omission. - Neil Parker -- Neil Parker No cute ASCII art...no cute quote...no cute nparker@cie.uoregon.edu disclaimer...no deposit, no return... parker@corona.uoregon.edu (This space intentionally left blank: ) parkern@jacobs.cs.orst.edu (Sorry about the proliferation of net addresses... the news reader on my usual machine is broken tonight, so I had to use another machine.)
msuacm@plains.NoDak.edu (MSU ACM Student Chapter) (11/10/90)
I need a bit of help with the 3.5" disk drive register listings. I know basically well how the 5.25" disk works from Beneath Apple Dos and a bunch of other miscellaneous publications... but what are the register listings for the 3.5" drive??? Also... could somebody PLEASE binscii me a WORKING copy of the Chameleon? One version I downloaded crashes into the monitor while trying to analyze what disks are online. I don't want the version that you ]EXEC into memory... I'd just like a working copy. Thanks to all who reply... Eric Ondler <msuacm@plains.nodak.edu>