engineering sample samples qualification cpu processor prozessor information mhz pictures core frequency chip packaging info ic x86 museum collection amd cyrix harris ibm idt iit intel motorola nec sgs sgs-thomson siemens ST signetics mhs ti texas instruments ulsi hp umc weitek zilog 4004 4040 8008 808x 8085 8088 8086 80188 80186 80286 286 80386 386 i386 Am386 386sx 386dx 486 i486 586 486sx 486dx overdrive 80187 80287 387 487 pentium 586 5x86 386dlc 386slc 486dx2 mmx ppro pentium-pro pro athlon duron z80 sparc alpha dec dirk oppelt
  LSI Logic R3000 RWB LR3220GC-25 [flip chip]   []   []   [hide data]   [close image viewer]  
A Read/Write Buffer coprocessor for the MIPS R3000 CPU.
The LR3220 Read-Write Buffer (RWB) is the main interface between the CPU and the remainder of the computer system. It provides the buffering necessary for decoupling the internal address and data buses. It enhances performance of MIPS R3000 based systems by buffering write and read operations. Using the LR3220 RWB, systems can perform memory write operations at the cycle rate of the processor, instead of stalling the processor to write data to memory. On memory read operations, the system uses the RWB to pass the read address to main memory, and latch the read data from memory. The LR3220 RWB generates parity, and then passes the data and parity to the processor. A single LR3220 RWB provides six-deep write buffering and one level of read buffering for 32 bits of address and 32 bits of data. It operates at the system clock rate.
The LR3220 buffers CPU/FPU stores for up to six pending writes. There is no gathering or reordering of writes in the LR3220. The data consistency conflicts between reads of write-buffered locations are automatically resolved by the memory controller. The LR3220 takes advantage of the memory system’s page mode cycles to retire writes within the same page each cycle. This results in a peak write bandwidth of 100 MBytes/second with a 25 MHz system clock.

» this chip on
Core Frequency:25 MHz
Board Frequency:25 MHz
Manufactured:week 04/1990
Made in:USA
Package Type:Ceramic
    more images: view image