I/O controllers mop up Pentium system functions

National Semiconductor has a new family of advanced input/output (I/O) controllers, the LPC (low pin count) bus-based PC87372 and PC87373 in standard 128-pin packages.

National Semiconductor has a new family of advanced input/output (I/O) controllers, the LPC (low pin count) bus-based PC87372 and PC87373 in standard 128-pin packages.

The devices meet the I/O needs of Intel Pentium 4 systems by integrating all required system control functions into a single chip.

Until today, the system control functions were accomplished with costly and bulky discrete logic scattered throughout the motherboard.

Manufacturers can now realise a 50% cost savings, 15% board space savings and simplified board routing with National's SuperI/O controller family.

In addition, both the PC87372 and PC87373 complement the functionality of the ICH4 (I/O controller hub) southbridge device, yielding an optimum platform solution.

"National's new LPC bus SuperI/O controllers are designed to meet the needs of today's PC system designers", said Jonathan Levy, Managing Director of National's Advanced PC Division.

"The devices are just one example of how National views system partitioning as the key to simplifying design, reducing system cost and bringing real value to the end user".

In addition to legacy support, the PC87372 and PC87373 incorporate a number of other features that benefit system designers.

Manufactured with National Semiconductor's advanced 0.18um CMOS process at its fabrication facility in South Portland, Maine, the control and quality grades are unmatched today, meeting and exceeding the levels demanded by Intel and top tier manufacturers.

The PC87372 and PC87373 integrate system control functions that complement the ICH4 I/O controller hub architecture, yielding a complete and cost-effective platform design.

These integrated system control functions include master reset generation, power supply good signals, power sequencing and control, interface voltage translation and isolation for the SMbus, as well as fan speed monitoring with alarms for slow running fans.

Until now, these system control functions were an afterthought, resulting in costly and bulky discrete logic scattered throughout the motherboard.

Legacy functions required for any PC system are implemented in the PC87372 and PC87373, and include an IEEE1284-compliant parallel port and an 8042-type keyboard and mouse controller.

The PC87372 supports a single 16550-type serial port, while the PC87373 has two serial ports and integrates standard game and midi functions.

Both devices also contain a floppy disk controller and, like all National SuperI/O devices, the floppy disk controller fully supports overrun and under run conditions during DMA transactions, does not lose data or status bytes, and is free of the NEC765A bug that has plagued many systems containing other SuperI/Os.

The PC87372 and PC87373, both in a 128-pin QFP, are sampling now.

In 1000 unit quantities, the single serial port PC87372 is priced at $2.10, and the dual serial port PC87373 is priced at $2.20.

Back to top