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.
* 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