High-performance 32-bit RISC CPU

The eSi-3250 32-bit CPU is targeted specifically for applications with high performance requiring caching, due to the use of slow on-chip memories such as eFlash, off-chip memories, or core/bus ratios greater than 1.

The processor features separate instruction and data caches that can be configured in size (from 1- 64kB) and associativity (direct mapped, 2 or 4-way associative) to increase performance and reduce power. The optional paged memory management unit (MMU) enables the implementation of virtual memory or memory protection. The 5-stage pipeline allows GHz clock frequencies to be achieved.

The eSi-3250’s instruction set includes everything you would expect in a high-performance processor. There are a number of optional application specific instructions and addressing modes. For example, a set of IEEE-754 compliant single-precision floating point instructions are available. Integer arithmetic instructions include a full 64 multiply and accumulate and divide. Bit manipulation instructions such as bitfield extract and insert, count leading zeros, population count, find first set and bit reverse can be included. Integer square root, absolute value, min/max, CRC and parity are also available. 32-bit SIMD instructions with 16-bit elements exploit data parallelism and reduce loop counts. Wait-for-interrupt instructions allow fast entry to low power states, enabling clock and power gating.

For those applications that require extreme performance or ultra low power operation, user-defined instructions and registers can be implemented.

Instructions are encoded in either 16 or 32-bits, with all of the commonly used instructions being encoded in 16-bits, maximizing code density and improving cache performance.

The processor supports both user and supervisor operating modes, with privileged instructions and memory areas, to allow an O/S kernel to be fully protected from user applications.

Hardware debug facilities include hardware breakpoints, watchpoints, trace, performance counters, null pointer detection and single-stepping for fast debugging of ROM, FLASH and RAM based programs.