GM82C765BPL

General Description

The GM82C765B is a CMOS LSI device which interfaces a host microprocessor to the floppy disk drive. It integrates the function of the Formatter/Controller, Data Separator. Write Precompensation, Data rate selection, Clock Generation, High Current Output Drivers, and TTL compatible Schmitt Trigger Receivers. The GM82C765B consists of a microprocessor interface, a microsequencer and a disk drive interface.

Features

• IBM PC compatible format (single and double density)
  – Floppy disk control and operations on chip
  – In PC AT mode, provides required signal qualification DMA channel
  – BIOS compatible and dual speed Spindle Drive support
• Integrates Formatter/Controller/Data Separation, Write Precompensation, Data rate Selection, Clock Generation, and drive interface Drivers and Receivers into one chip
• Multisector and Multitrack transfer capability.
• Direct Floppy Disk Drive interface with no buffers needed
  – 48mA sink output drivers
  – Schmitt trigger Line Receivers
• Enhanced Host Interface:
  – Supports 12MHz, 286 u-processor
  – Capable of driving 20 LSTTL Load
• Address mark detection circuitary internal to Floppy Disk Controller
• On chip Clock Generation Two TTL Clock Inputs for 40-DIP
• Two XTAL oscillator circuits for 44-Quad, PLCC
• User programmable Track Stepping Rate and Head load/unload time
• Drivers up to four Floppy or micro Floppy Disk Drives
• Data transfer DMA or non-DMA mode
• Parallel seek operations on up to four Drives
• Internal power up reset circuitry
• READ/WRITE access compatible register with 8 or 12MHz 286 microprocessor with 0 wait states.
• DMA timing corrected.
• LOW POWER CMOS, +5V SUPPLY