Hardware Overview
The RM5231A offers a high-level of integration targeted at high-performance embedded applications. The key elements of the RM5231A are briefly described below.

Features
• Dual Issue superscalar microprocessor
    • 250, 300, and 350 MHz operating frequencies
    • Up to 420 Dhrystone 2.1 MIPS
• System interface optimized for embedded applications
    • 32-bit system interface lowers total system cost
    • 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
• 128-pin QFP package