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
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