80960JA Datasheet, PDF (12/77 Pages) Intel Corporation – EMBEDDED 32-BIT MICROPROCESSOR

80960JA/JF/JD/JT 3.3 V Microprocessor
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Test Features
The 80960Jx incorporates numerous features which enhance the user’s ability to test both the
processor and the system to which it is attached. These features include ONCE (On-Circuit
Emulation) mode and Boundary Scan (JTAG).
The 80960Jx provides testability features compatible with IEEE Standard Test Access Port and
Boundary Scan Architecture (IEEE Std. 1149.1).
One of the boundary scan instructions, HIGHZ, forces the processor to float all its output pins (ONCE
mode). ONCE mode can also be initiated at reset without using the boundary scan mechanism.
ONCE mode is useful for board-level testing. This feature allows a mounted 80960Jx to
electrically “remove” itself from a circuit board. This allows for system-level testing where a
remote tester — such as an in-circuit emulator — can exercise the processor system.
The provided test logic does not interfere with component or circuit board behavior and ensures
that components function correctly, connections between various components are correct, and
various components interact correctly on the printed circuit board.
The JTAG Boundary Scan feature is an attractive alternative to conventional “bed-of-nails” testing.
It can examine connections which might otherwise be inaccessible to a test system.
Memory-Mapped Control Registers
The 80960Jx, though compliant with i960 series processor core, has the added advantage of
memory-mapped, internal control registers not found on the i960 Kx, Sx or Cx processors. These
give software the interface to easily read and modify internal control registers.
Each of these registers is accessed as a memory-mapped, 32-bit register. Access is accomplished
through regular memory-format instructions. The processor ensures that these accesses do not
generate external bus cycles.
Data Types and Memory Addressing Modes
As with all i960 family processors, the 80960Jx instruction set supports several data types and formats:
• Bit
• Bit fields
• Integer (8-, 16-, 32-, 64-bit)
• Ordinal (8-, 16-, 32-, 64-bit unsigned integers)
• Triple word (96 bits)
• Quad word (128 bits)
The 80960Jx provides a full set of addressing modes for C and assembly programming:
• Two Absolute modes
• Five Register Indirect modes
• Index with displacement
• IP with displacement
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