AT&T 6300 Service Manual page 35

SYSTEM OVERVIEW
Mini-FloPPY Disk Interface
The MFD Interface has two major functions:
• It manages the logic and control circuitry required in
recording data onto and reading data from the MFD Units.
• It initially formats new disks.
The MFD Interface is physically located on the Motherboard. Its
chief component is the NEC J.LPD765 Floppy Disk Controller (or
equivalent). This controller contains the circuitry and control
functions for interfacing the 8086 CPU to the MFD Units. The
controller operates in a DMA mode during data transfers. In this
way, the 8086 CPU need only load the command required into the
controller and all data transfers occur under the control of the
J.LPD765 and the DMA controller. The J.LPD765 supports 15 separate
commands.
2-19