80960HA/HD/HT
10
Datasheet
In addition to expanded clock frequency options, the 80960Hx provides essential enhancements for
an emerging class of high-performance embedded applications. Features include a larger
instruction cache, data cache, and data RAM than any other 80960 processor to date. It also boasts
a 32-bit demultiplexed and pipelined burst bus, fast interrupt mechanism, guarded memory unit,
wait state generator, dual programmable timers, ONCE and IEEE 1149.1-compliant boundary scan
test and debug support, and new instructions.
2.1
The i960
®
Processor Family
The i960
®
processor family is a 32-bit RISC architecture created by Intel to serve the needs of
embedded applications. The embedded market includes applications as diverse as industrial
automation, avionics, image processing, graphics and communications.
Because all members of the i960 processor family share a common core architecture, i960
applications are code-compatible. Each new processor in the family adds its own special set of
functions to the core to satisfy the needs of a specific application or range of applications in the
embedded market.
2.2
Key 80960Hx Features
2.2.1
Execution Architecture
Independent instruction paths inside the processor allow the execution of multiple, out-of-sequence
instructions per clock. Register and resource scoreboarding interlocks maintain the logical integrity
of sequential instructions that are being executed in parallel. To sustain execution of multiple
instructions in each clock cycle, the processor decodes multiple instructions in parallel and
simultaneously issues these instructions to parallel processing units. The various processing units
are then able to independently access instruction operands in parallel from a common register set.
Local Register Cache integrated on-chip provides automatic register management on call/return
instructions. Upon a call instruction, the processor allocates a set of local registers for the called
procedure, then stores the registers for the previous procedure in the on-chip register cache. As
additional procedures are called, the cache stores the associated registers such that the most recently
called procedure is the first available by the next return (ret) instruction. The processor may store up
to fifteen register sets, after which the oldest sets are stored (spilled) into external memory.
The 80960Hx supports the 80960 architecturally-defined branch prediction mechanism. This
allows many branches to execute with no pipeline break. With the 80960Hx’s efficient pipeline, a
branch may take as few as zero clocks to execute. The maximum penalty for an incorrect prediction
is two core clocks.
2.2.2
Pipelined, Burst Bus
A 32-bit high performance bus controller interfaces the 80960Hx core to the external memory and
peripherals. The Bus Control Unit features a maximum transfer rate of 160 Mbytes per second (at a
40 MHz external bus clock frequency). A key advantage of this design is its versatility. The user
may independently program the physical and logical attributes of system memory. Physical
attributes include wait state profile, bus width, and parity. Logical attributes include cacheability
and Big or Little Endian byte order. Internally programmable wait states and 16 separately
configurable physical memory regions allow the processor to interface with a variety of memory
