NEC IMAGE P100E Service Manual

Also see for IMAGE P100E - SERVICE: Manual

Contents

1-10 Technical InformationThe dual processor upgrade option is installed in a 320-pin PGA, zero-insertion-force (ZIF)socket on the system board.Secondary CacheThe 16-KB primary cache (8 KB data and 8 KB instruction) is integrated into theprocessor. The system board also provides 256 KB of 9-ns, synchronous secondary cachememory that is external to the processor. Cache memory improves read performance byholding copies of code and data that are frequently requested from the system memory bythe processor. Cache memory is not considered part of the expansion memory.The cache is connected directly to the processor address bus (direct mapped) and usesphysical addresses (32-bit line size). A bus feature known as Burst enables fast cache fills.Memory areas (pages) can be designated as cacheable or non-cacheable by software. Thecache can also be enabled and disabled by software.The write strategy of the secondary cache is write-back for single processor systems andwrite-through for dual processor systems. If the write is a cache hit, an external bus cycle isgenerated and information is written to the cache. Any area of memory can be cached in thesystem. Non-cacheable portions of memory are defined by software. The cache can becleared by software instructions.Flash ROMMachine language programs known as the system's basic input/output system (BIOS) arestored in a 256K x 8 Flash ROM chip (28F020 PLCC) mounted on the system board. Thesystem BIOS, EISA extensions, PCI extensions, Automatic Configuration Unit (ACU)loader, and Video BIOS reside in the upper 64K of the ROM area. The lower 64K of ROMincludes the SCSI BIOS and ACU code.The flash ROM allows the BIOS to be upgraded with the BIOS Update utility withoutremoving the ROM (see Section 4, Maintenance and Troubleshooting). The BIOS can onlybe reprogrammed by powering on the system with the BIOS Update utility diskette indrive A.The BIOS programs execute the Power-On Self-Test (POST), initialize the processorcontrollers, and interact with the display, diskette drives, hard disks, communicationdevices, and peripherals. The system BIOS also contains the Setup program and providesVGA controller support. The ROM BIOS is always copied into RAM (shadowing) formaximum performance.System BIOS is located between E0000h-FFFFFh and supports shadowing and shadowedmemory. System BIOS is write protected and automatically enabled.The video BIOS is combined with the system BIOS and is located between C0000h andC7FFFh. The system memory map is shown in Table Section 1-2.