NEC POWERMATE VE - SERVICE MANUAL 05-1996 Service Manual

Also see for PowerMate V100e: Service manual

Contents

NEC POWERMATE VE - SERVICE MANUAL 05-1996 Service Manual Manual pdf 19 page image

1-6 Technical InformationSecondary CacheThe system board contains the connector for an optional 256 KB secondary cache, externalto the processor. The optional cache can be 15-ns asynchronous or 20-ns synchronouspipeline burst.Cache allows data to be sent or received from cache with one wait state burst. Cachememory improves read performance by holding copies of code and data that are frequentlyrequested from the system memory by the processor. Cache memory is not considered partof the expansion memory.System and Video BIOSThe system and video BIOS are stored in a 1 MB (128 KB by 8) flash memory device(Flash ROM). The system BIOS uses 64 KB, the video BIOS uses 32 KB, and 32 KB isreserved. The system BIOS is capable of being shadowed and cached through the system’sSetup utility (see Section 2 for Setup information). System BIOS is write protected andautomatically enabled.The BIOS programs execute the Power-On Self-Test, initialize processor controllers, andinteract with the display, diskette drives, hard disks, communication devices, andperipherals. The system BIOS also contains the Setup utility. The hardware setup defaultcopies the ROM BIOS into RAM (shadowing) for maximum performance.The Flash ROM allows the system and video BIOS to be upgraded with the BIOS Updateutility, without removing the ROM (see Section 2 for further information on the BIOSUpdate utility). The Flash ROM supports the reprogramming of the system BIOS and thevideo BIOS.The system memory map is shown in Table Section 1-3.Table Section 1-3 System Memory MapMemory Space Size FunctionFFF80000-FFFFFFFF 512 KB BIOS ROM04000000-07FFFFFF 64 MB L2 cache (Non-Cacheable with less than 512 KBSRAM)L1 cache (Cacheable)01000000-03FFFFFF 48 MB Always cachable00F00000-00FFFFFF 1 MB Optional memory space gap00100000-00EFFFFF 14 MB Cachable000F0000-000FFFFF 64 KB System BIOS (Shadowed in DRAM)000C8000-000EFFFF 160 KB Expansion region (Shadowed in DRAM)