SOYO SY-7VCA user manual

Motherboard Description SY-7VCA

operating environments. Both Window 95 VxD and Windows 98 /NT5.0 mini port drivers are supported for interoperability with major AGP-based 3D and DVD- capable multimedia accelerators.

The VT82C694X supports two 32-bit 3.3/5V system buses (one AGP and one PCI) that are synchronous/ pseudo-synchronous to the CPU bus. The chip also contains a built-in bus-to-bus bridge to allow simultaneous concurrent operations on each bus. Five levels (double words) of post write buffers are included to allow for concurrent CPU and PCI operation. For PCI master operation, forty-eight levels (double words) of post write buffers and sixteen levels (double words) of prefetch buffers are included for concurrent PCI bus and DRAM/cache accesses. The chip also supports enhanced PCI bus commands such as Memory-Read-Line, Memory-Read- Multiple and Memory-Write-Invalid commands to minimize snoop overhead. In addition, advanced features are supported such as snoop ahead, snoop filtering, L1 write-back forward to PCI master, and L1 write- back merged with PCI post write buffers to minimize PCI master read latency and DRAM utilization. Delay transaction and read caching mechanisms are also implemented for further improvement of over all system performance.

The 352-pin Ball Grid Array VT82C686A PCI to ISA bridge supports four levels (double words) of line buffers, type F DMA transfers and delay transaction to allow efficient PCI bus utilization The VT82C686A also includes an integrated keyboard controller with PS/2 mouse support, integrated DS12885 style real time clock with extended 256 byte CMOS RAM, integrated master mode enhanced IDE controller with full scatter/ gather capability and extension to UltraDMA-33/66 for 33/66 MB/sec transfer rate, integrated USB interface with root Hub and two function ports with built-in physical layer transceivers, Distributed DMA supports, and On Now/ ACPI compliant advanced configuration and power management interface.

For sophisticated power management, the Via 694X provides independent clock stop control for the CPU/SDRAM, PCI, and AGP buses and

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