ALi Northbridge for Pentium II with AGP, PCI and Memory Controller

ALADDiN-Pro 2 is a new generation Pentium II class system chip set which continuously supports cost effective desktop PCs. It consists of two BGA packed chips, the M1621 and M1543C. The M1621 is an AGP, memory and I/O controller and a data path with multi-port buffers for data acceleration.

With an external I/O APIC controller, it can support multiple Pentium II processors. The M1543C is a high integration bridge between PCI and ISA bus, providing full PCI and ISA compatible functions. The built-in Mega I/O in M1543C is the most advanced Super I/O controller solution to basic IBM PC, XT, AT peripherals. It incorporates three full function universal asynchronous receiver/ transmitters (UARTs) ( Two for COM1/COM2 and One is dedicated for IR support), a Parallel Port with various mode support, and a Floppy Disk Controller (FDC) incorporating high performance internal data separator with send/receive 16 bytes FIFOs. The serial ports support two high performance 16450/16550 compatible UARTs with send/receive 16 bytes FIFOs and a programmable baud rate generator. For the complete system architecture and specification, M1543C has the dedicated pins and COM port for the IR support, which means, the motherboard still can support two serial ports outside and have the IR support at the same time. The wireless communications supported by M1543C includes IrDA 1.0 (SIR), IrDA 1.1 (MIR and FIR), and Sharp-IR.

The Parallel Port features basic functions such as standard mode, enhanced mode, and high speed mode and is compliant to SPP, PS/2, EPP, ECP, and 1284 standard. The Parallel Port also includes protection circuit against damage caused when printer is powered up, or is operated at higher voltages. The Floppy Disk Controller can support up to 1 Mbps data transfer, three-mode driver, and swappable drives A & B. Furthermore, M1543C also has high performance power management for FDC, UARTs and Parallel Port to meet green requirement.

ALADDiN-Pro 2 employs various techniques to improve the memory and I/O throughput to match up with the advanced super-scalar, super-pipelined Pentium II class processors. On the memory subsystem side, the Pentium II data bus utilization is minimized. The pipelined memory cycle design helps hidden precharge latency and refresh cycles. Different ways of configurations optimize the performance for a wide range of memory size. On the I/O subsystem side, deep buffers shadow the latency for both PCI devices initiated master read and write. To support the 3D graphics function, M1621 supports a 66 MHz graphics PCI bus, and 1x/2x AGP mode.

Reliability and performance are the keys to PC design. They are also the major targets of ALADDiN-Pro design for Pentium II. Parity protection over PCI bus and independent EC and ECC protection over memory subsystem is used. Programmable SMM address mapping is also provided