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Functional Description 4–7
ISA Bus Devices
4.3.1 Combination Controller Chip
The AlphaPC 164SX uses the Standard Microsystems Corporation FDC37C669
combination controller chip (see Figure 4–4). It is packaged in a 100-pin QFP con-
figuration. The chip provides the following ISA peripheral functions:
• Diskette controller – Software compatible to the Intel N82077 FDC. Inte-
grates the functions of the formatter/controller, digital data separator, write
precompensation, and data-rate selection logic requiring no external filter
components. Supports the 2.88-MB drive format and other standard diskette
drives used with 5.25-inch and 3.5-inch media. FDC data and control lines are
brought out to a standard 34-pin connector (J11). A ribbon cable interfaces the
connector to one or two diskette drives.
• Serial ports – Two UARTs with full modem control, compatible with NS16450
or PC16550 devices, are brought out to two separate onboard, 9-pin
D-subminiature connectors (J3).
• Parallel port – The bidirectional parallel port is brought out to an onboard
25-pin connector (J13). It can be brought out through a 25-pin female
D-subminiature connector on the bulkhead of a standard PC enclosure.
An onboard clock generator chip supplies a 14.3-MHz reference clock for the dis-
kette data separator and serial ports.