beo@maestro.htsa.aha.nl (BeO de PeO) (09/10/90)
Hello netters, I've got a PC diskdrive and want to use it as a second drive for my A500, but it won't work OK. I checked out the pin-names and saw they were the same, so I swapped it with my internal drive to check if it would work. It worked fine, apart from one thing: my A500 would not recognize the disk-change. Is this due to the diskdrive or does the interfacing require some extra hardware? If someone could help me out, ThanxAdvanceInVeryMuch!!! (Please mail me, I can not read News regular, and the expiration time is seven days here) Greetings, ___ ___ | She's dressed in black again / \ / \ Jan van Veen | And I'm falling down again | o | o | beo@maestro.htsa.aha.nl | Down on the floor again \___/ \___/ Amsterdam, Netherlands | I'm begging for more again | \ | But oh, what can you do | ____\ | When she's dressed in black | | M.L. Gore (Depeche Mode)
jms@tardis.Tymnet.COM (Joe Smith) (09/26/90)
In article <2371@maestro.htsa.aha.nl> beo@maestro.htsa.aha.nl (Jan -BeO de PeO- van Veen) writes: > I've got a PC diskdrive and want to use it as a second drive for > my A500, but it won't work OK. I checked out the pin-names and saw > they were the same, so I swapped it with my internal drive to check > if it would work. It worked fine, apart from one thing: my A500 > would not recognize the disk-change. Is this due to the diskdrive > or does the interfacing require some extra hardware? This comes up repeatedly. The answer is that you do need extra hardware. In particular, the 23-pin connector has nonstandard signals on pins 1, 8, 21. Many floppy drives do not supply the signal for pin 11. Pin 1 (RDY*) If motor on: indicates disk is initialized and up to speed. If motor off: identification mode data, clocked in by SELxB. Pin 8 (MTRXD*) Motor on data. Expected to be latched by a flip-flop clocked by the active transition of SELxB. Pin 21 (SEL1B*) Select for drive 1. (Pin 9 is SEL2B*, pin 20 is SEL3B*) To turn motor on, assert MTRXD, then assert SELxB. (Motor is expected to stay on even of both MTRXD and SELxB are then deasserted.) To turn motor off, deassert MTRXD, then assert SELxB. (Motor is expected to stay off even if MTRXD is asserted later, or SELxB is deasserted.) To read the identification data from the external drive, first turn the motor on then off to re-initialize the ID flip-flop or ID shift register. Then enter a loop to read 32 bits of ID from the drive. The loop is: { drive SELxB active, read data from RDY (pin 1), drive SELxB inactive }. The most significant bit is received first. If the ID is $00000000 then no Amiga-compatible drive is connected. If the ID is $FFFFFFFF then a 3.5 inch 720K (880K) drive is connected. If the ID is $55555555 then a 5.25 inch 360K (440K) drive is connected. Pin 11 (CHNG*) is asserted at powerup and whenever the floppy is ejected. It says asserted until a disk is inserted and the heads are stepped. (Click.) If the disk drive does not supply this signal, the Amiga will not notice disk changes. Source: Pages 310 and 311 of the Hardwar Reference Manual (1989 edition). -- Joe Smith (408)922-6220 | SMTP: jms@tardis.tymnet.com or jms@gemini.tymnet.com BT Tymnet Tech Services | UUCP: ...!{ames,pyramid}!oliveb!tymix!tardis!jms PO Box 49019, MS-C41 | BIX: smithjoe | 12 PDP-10s still running! "POPJ P," San Jose, CA 95161-9019 | humorous dislaimer: "My Amiga 3000 speaks for me."