
PMC-Sierra
Hardware Overview
The RM5261A offers a high-level of integration targeted at high-performance embedded applications. The key elements of the RM5261A are briefly described below.
FEATUREs
• Dual Issue superscalar microprocessor
• 250, 300, and 350 MHz operating frequencies
• Up to 420 Dhrystone 2.1 MIPS
• High-performance system interface
• 64-bit multiplexed system address/data bus for optimum price/performance
• High-performance write protocols maximize uncached write bandwidth
• Processor clock multipliers 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 7, 8, 9
• IEEE 1149.1 JTAG boundary scan
• Integrated on-chip caches
• 32 KB instruction and 32 KB data — 2 way set associative
• Per set locking
• Virtually indexed, physically tagged
• Write-back and write-through on a per page basis
• Pipeline restart on first doubleword for data cache misses
• Integrated memory management unit
• Fully associative joint TLB (shared by I and D translations)
• 48 dual entries map 96 pages
• Variable page size (4 KB to 16 MB in 4x increments)
• High-performance floating-point unit: up to 700 MFLOPS
• Single cycle repeat rate for common single-precision operations and some double-precision operations
• Two cycle repeat rate for double-precision multiply and double precision combined multiply-add operations
• Single cycle repeat rate for single-precision combined multiply-add operation
• MIPS IV instruction set
• Floating point multiply-add instruction increases performance in signal processing and graphics applications
• Conditional moves to reduce branch frequency
• Index address modes (register + register)
• Embedded application enhancements
• Specialized DSP integer Multiply-Accumulate instructions and 3-operand multiply instruction
• I and D cache locking by set
• Optional dedicated exception vector for interrupts
• Fully static 0.18 micron CMOS design with power down logic
• Standby reduced power mode with WAIT instruction
• 1.65 V or 1.8 V core with 3.3 V or 2.5 V I/O
• 208-pin QFP package