Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: Notesfiles $Revision: 1.7.0.10 $; site uok.UUCP
Path: utzoo!watmath!clyde!cbosgd!ihnp4!inuxc!pur-ee!uiucdcs!okstate.UUCP!uok.UUCP!dvgarlan
From: dvgarlan@uok.UUCP
Newsgroups: net.micro.amiga
Subject: Re: Hooking an IBM drive to the Amiga
Message-ID: <64500005@uok.UUCP>
Date: Tue, 8-Apr-86 13:51:00 EST
Article-I.D.: uok.64500005
Posted: Tue Apr  8 13:51:00 1986
Date-Received: Fri, 18-Apr-86 20:27:11 EST
References: <243@oberon.UUCP>
Lines: 66
Nf-ID: #R:oberon.UUCP:243:uok.UUCP:64500005:000:3516
Nf-From: uok.UUCP!dvgarlan    Apr  8 12:51:00 1986


 Schematic:
 ---------
 
+++++++++++++++++++++++++                         (A)
                         +                         | 
  Symbols:               +                         | 4 
  -------    resistor:   +                         o---|\   6
    ______               +                         |   | |O------
   !      !        |     +                         o---|/        
   ! chip !        \     +                           5
   !______!        /     +
                   \     +          (A)              
     NAND gate:    |     +           |
                         +           |
     -----|\             +           o-----o-----o-----o
          | |O----       +           |     |     |     |
     -----|/             +       ____|_____|_____|_____|______ 
                         +      !                             !
  junction   no-junction +      !    10    11    12    13     !   8
                         +      !                           Q !-----
      |           |      +      !                             !
    --o--       --|--    +      !         1/2  7474         _ !
      |           |      +      !                           Q !-----
                         +      !                             !   9
+++++++++++++++++++++++++       !_____________________________! 

 
             +5v           +5v          +5v           NAND gates are 7438
              ^             ^            ^            All resistors 1K
              |             |            |            
              \             \            \            +++++++++++++++++++
         1K   /   (A)   1K  /        1K  /            + From disk drive +
              \    ^        \            \            + power supply:   +
              |    |        |     1      |            +                 +
              |    o--------o------|\  3 |            + Pin 14- +5v     +
              |             |      | |O--o            + Pin  7- GND     +
 SEL1B(21) >--o-------------|---o--|/    |            +++++++++++++++++++
                            |   | 2      |
                            |   o--------|--------------o
             +5v            |            |              |
              ^             |       o----o              |
              |           1 |     3 |    |              |
              \   __________O_______|__  |              |
          1K  /   !        CLR      \/!  |              |
              \   !                   !  |  9           |
              | 2 !                   !  o---|\  8      |
 MTRXD(8)  >--o---! D                 ! 5    | |O----o  |
                  !                 Q !------|/      |  |
             +5v  !                   !    10        |  |
              ^   !     1/2 7474      !              |  |
              |   !                   !              |  |
              \   !                 _ ! 6            |  |
          1K  /   !                 Q !---o          |  |
              \   !                   !   |          |  o---> DRIVE ENABLE
              | 4 !                   !   |          |
 DRESB(10) >--o---O PR                !   | 12       |
              |   !___________________!   o----|\ 11 |
              |                                | |O---------> HUB MOTOR DRIVE
              o--------------------------------|/    |
                                            13       | 
                                                     |
 RDY(1)  <-------------------------------------------o
 

WHERE IS (A)----- COMING FROM???