The WD2797 performs data formatting and control operations for interfacing between a host CPU and 8-inch, 5.25-inch, or RS 3.5-inch, floppy disc drives. Single chip design minimizes interface components and offers both IBM 3740 compatibility in single density mode (FM) and systems 34 compatibility in double density mode (MFM). The 2797 contains all the features of its predecessor the 1797 together with a high-performance phase-locked-loop data separator and write pre-compensation logic. Double-density mode has the write per compensation automatically set to a value programmed via an external potentiometer. the CPU interface is T.T.L. compatible consisting of an 8-bit true data bus utilized for data, status, and control word transfers. Data outputs are also T.T.L. compatible and a side select output is included for controlling double-sided drives. 40-pin d.i.l. plastic package, equivalent to WD2797APL-02.
