Compaq 164SX - Manual (Page 47)

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.