HP XA The Super I/O Controller (NS 82317), FDC, RTC, Controller, Serial / parallel, Devices on the ISA Bus

2 System Board

Devices on the ISA Bus

Devices on the ISA Bus

ISA Device	Index	Data
Ultra I/O	2Eh	2Fh
Little Ben (HP ASIC)	96h	97h

	The Super I/O Controller (NS 82317)
	The Ultra I/O chip (NS 82317) provides the control for two FDD devices,
	one serial port and one bidirectional multi-mode parallel port.
Serial / parallel	The 9-pin serial port (whose pin layouts are depicted on page 71) supports
communications ports	RS-232-C and are buffered by 16550A UARTs, with 16 Byte FIFOs. They can
	be programmed as COM1, COM2, COM3, COM4, or disabled.
	The 25-pin parallel port (also depicted on page 71) is Centronics
	compatible, supporting IEEE 1284. It can be programmed as LPT1, LPT2, or
	disabled. It can operate in the following four modes:

❒Standard mode (PC/XT, PC/AT, and PS/2 compatible).

❒Bidirectional mode (PC/XT, PC/AT, and PS/2 compatible).

❒Enhanced mode (enhanced parallel port, EPP, compatible).

❒High speed mode (MS/HP extended capabilities port, ECP, compatible).

FDC	The integrated flexible disk controller (FDC) supports any combination of
	two of the following: tape drives, 3.5-inch flexible disk drives, 5.25-inch
	flexible disk drives. It is software and register compatible with the 82077AA,
	and 100% IBM compatible. It has an A and B drive-swapping capability and a
	non-burst DMA option.
RTC	The real-time clock (RTC) is 146818A-compatible. With an accuracy of
	20 ppm (parts per million). The configuration RAM is implemented as 256
	bytes of CMOS memory.
Keyboard and Mouse	The computer has an 8042-based keyboard and mouse controller. The
Controller	connector pin layouts are shown on page 71.

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