Pages of Understanding the Apple II - Ch. 9 -The Disk Controller

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• page 9-1
• page 9-2
  • functional diagram of the disk interface
• page 9-3
  • disk ii overview
• page 9-4
  • data transfer in disk i/o
• page 9-5
  • power supply
  • the disk ii drive
  • the DRIVE ENABLE input
  • the head positioning mechanism
• page 9-6
  • simplified functional diagram of the disk ii drive
• page 9-7
  • a stepping motor
  • writing to the disk
• page 9-8
  • the write protect switch
• page 9-9
  • the read pulse
• page 9-10
  • block diagram of the disk ii controller
• page 9-11
  • disk ii controller commands
  • the bootstrap ROM
  • the command decoder
  • the disk ii controller
• page 9-12
  • schematic: the disk ii controller
• page 9-13
  • drive off/on and drive select
  • head positioning commands
  • read/write
• page 9-14
  • functions of the $C08C,X/$C080,X and $C08E/$C08F switch
  • shift/load
  • the logic state sequencer and data register
• page 9-15
  • logic state sequencer command
• page 9-16
  • decoding the contents of the sequencer ROM
• page 9-17
  • the write sequence
• page 9-18
  • BASIC listing: program to list state sequencer ROM
• page 9-19
• page 9-20
  • the DOS 3.2 logic state sequencer
• page 9-21
  • the DOS 3.3 logic state sequencer
• page 9-22
• page 9-23
  • timing example: sequencer control while changing the READ/WRITE or SHIFT/LOAD switches
  • timing example: switcing to write after checking write protect
• page 9-24
  • disk data formats
• page 9-25
  • flowchart of the write sequence
• page 9-26
• page 9-27
• page 9-28
  • diskette formatting
• page 9-29
  • the READ sequence
• page 9-30
  • syncing the READ sequence to data
• page 9-31
  • simplified flowchart of the read sequence
• page 9-32
  • decision points for reading zeros
• page 9-33
  • read performance of the logic state sequencer
• page 9-34
  • programming examples from RWTS
  • the read sequence as a finite state automoton
• page 9-35
  • Jim Aolto finite state automotom diagram
• page 9-36
  • flowchart of the RWTS routine
• page 9-37
  • drive turn-on
• page 9-38
  • positioning the head in RWTS
• page 9-39
  • formatting the disk (command 4)
• page 9-40
  • reading and writing sectors (commands 1 and 2)
• page 9-41
  • write routines
• page 9-42
  • read routines
• page 9-43
  • installing a write protect switch on the disk ii drive
• page 9-44
• page 9-45
• page 9-46