FLOPPYTYPE IDENTIFICATION
          -------------------------
          
          by Karsten Schmidt (Chip Special)
          
          
            So many various types of floppydrives like for our hot loved
          XL/XE doesn't exist for every homecomputer. But ATARI was busy
          in the "good old time" and also other firms and persons have
          developed more or less well enhancements and absolute new types
          of floppies. So the most common drives are:
          
          * ATARI 1050
          * ATARI 1050 + SPEEDY/HAPPY
          * ATARI 1050 + Turbo 1050
          * ATARI 1050 + US Doubler
          * ATARI XF551
          * F2000 (II) and
          * HDI (High Density Interface for 3.5" floppies by Erhard Puetz)
          
            During coding my diskeditor I had this stupid idea to show the
          name of the current diskdrive. Of course there're also more
          important things like that, where it's pretty nice to know the
          type of the connected floppy. But now the question was: How to
          realize it?
          
          1. XF 551
          ---------
            Well, fortunately the OS supports us with a very powerful
          SIO-command: GET STATUS ($53) Many of you probably don't know,
          how flexible this nice command is. Beside the current density of
          the disk, you can identify e.g. the XF551 too. After receiving
          the STATUS-command every floppy sends 4 Bytes back to the XL.
          But only the third byte is significiant for our purposes, it
          contains the timeout value for formatting a disk. If this value
          is $FE, then it's sure, that this drive is a ATARI XF551. A very
          positive effect would be, if we now activate the intern
          "speeder" of this drive by setting a higher datatransfer rate:
          
           INIT_HS  LDA #<IRQ
                    LDX #>IRQ
                    STA $20A
                    STX $20B
                    RTS
           IRQ      LDA #$10
                    STA $D204
                    JMP $EB2C
          
          2. SPEEDY/HAPPY enhancement
          ---------------------------
















            To realize a SPEEDY or HAPPY (it's nearly the same in this
          case) we use the commands GET SIO-LENGTH and SEND SIO ($68/$69).
          If there occurs an error, we know that there's no SPEEDY. Else
          we can load the High-Speed-SIO and work with this routine
          instead of $E459 (use this highspeed-sio only when transfering
          sector datas!):
          
                    LDX #11
           COPY     LDA SIOTAB,X
                    STA $0300,X
                    DEX
                    BPL COPY
                    JSR $E459
                    BMI NOSPEEDY
                    INC $0302
                    LDA #$40
                    STA $0303
                    LDA #<HSSIO
                    LDX #>HSSIO
                    STA $0304
                    STX $0305
                    JSR $E459
                    BMI NOSPEEDY
                    RTS
           SIOTAB   DFB $31   FLOPPY ID.
                    DFB 1     DRIVE #
                    DFB $68   GET SIOLENGTH
                    DFB $40   READ STATUS
                    DFW $0308 BUFFERADDRESS
                    DFB 7     TIMEOUT
                    DFB 0     DUMMYBYTE
                    DFW 2     DATALENGTH (1 WORD)
                    DFW HSSIO NEW SIO ADDRESS
            ;
           HSSIO     .        FROM HERE THE
                     .        NEW SIO-ROUTINE
                     .
          
          3. Floppy 2000 II
          -----------------
            Surely you think, this floppy is also a speedy drive, but we
          can specify it more exactly with the SIO-command GET SIOSPEED
          ($3F). A common SPEEDY drive uses the value $09 as timer for
          data transfers. However the F2000 works with the value $0A. But
          it doesn't mean, that the F2000 is slower than a normal SPEEDY,
          because the F2000 works with an higher system tactrate, namely
          exact 1.04 MHz. The value for a normal 1050 is $28 (in some
          literature it's said, this value is $10. But that's false!!!).
          
          
















          4. HDI 3.5"
          -----------
            This floppy controller is very popular in Germany. It allows
          to connect up to 4 HD drives and furthermore it's compatible
          with the legendary HAPPY enhancement. To realize this type, we
          have to use the command GET DRIVECONFIGURATION ($4E). In that
          configuration table the 2nd byte (of 12) is interesting for us.
          It stands for the STEP RATE of the drive and is $02 if an HDI is
          connected (else $01).
          
                    LDX #11
           COPY     LDA PERCOM,X
                    STA $0300,X
                    DEX
                    BPL COPY
                    JSR $E459
                    BMI NORM1050
                    LDA BUFFER+1
                    CMP #2
                    BNE NO_HDI
                     .
                     .
                     .
           SIOTAB   DFB $31         FLOPPY ID.
                    DFB 1           DRIVE #
                    DFB $4E         GET PERCOM
                    DFB $40         READ STATUS
                    DFW BUFFER      BUFFERADDRESS
                    DFB 7           TIMEOUT
                    DFB 0           DUMMYBYTE
                    DFW 12          BLOCKLENGTH
                    DFW 0           THING OF NO
                                    INTEREST
           BUFFER   DFW 0,0,0,0,0,0
          
          
            How you can realize the US Doubler and the Turbo 1050 I don't
          know, but if YOU know it, please write me a small letter
          (address at the end of this article)!!!
          
            Before I finish this text, I also want to add some info about
          the density inquiry with the command $53 (see also XF551). In
          the highest three bits of the first statusbyte we can read the
          density of the current disk in drive. Therefor we have to mask
          all other bits at first (AND #$E0). Now there're following
          possible combinations:
          
          value     density
          
           $20      double
















           $40      single
           $60      quad
           $80      medium
          
          (Some people say that bit 6 isn't used, but that's not true how
          I found out...)
          As you perhaps know the XF has big problems with realizing the
          density. It sends also $60 to the ATARI if the disk is only in
          double density. So you have to try to read a sector (e.g. $5A0)
          from the backside, to find out if it's double or quad!
          ATTENTION! You have to wait at least 5/50 seconds between
          executing GET STATUS and try to read this sector!!!
          
          
            So. All clearnesses removed? I hope so... :-)
          
          
          
          If questions or anything else,write to:
          
                        Chip Special Software
                        Karsten Schmidt
                        Paul-Bertz-Str.107
                        O-9044 Chemnitz