4-6Theory of Operation
4.3.3 ALI M1521 (PCI, Cache and Memory Controller)The ALADDIN-III consists of tow chips, ALI M1521 and M1523 to give a 586 class system the
complete solution with the most up-to-date feature and architecture for the new multimedia/
multithreading operating system. It utilizes the BGA package to improve the AC characterization,
resolves system bottleneck and make the system manufacturing easier. The ALADDIN-III gives a
highly-integrated system solution and a most up-to-date system architecture including the UMA,
ECC, PBSRAM, SDRAM/BEDO and multi-bus with highly efficient, deep FIFO between the buses,
such as the HOST/PCI/ISA dedicated IDE bus.
The M1521 provides a complete integrated solution for the system controller and data path
components in a Pentium-based system. It provides a 64-bit CPU bus interface, 32-bit PCI bus
interface, 64/72 DRAM data bus with ECC or parity, secondary cache interface including pipeline
burst SRAM or asynchronous SRAM, PCI master to DRAM interface, four PCI master arbiters and a
UMA arbiter. The M1521 bus interfaces are designed to interface with 3V and 5V buses.
The chip pinouts are provided in Figure 4-2.