80960JD datasheet(12/78 Pages) INTEL

12 / 78 page

80960JA/JF/JD/JT 3.3 V Microprocessor

Advance Information Datasheet

2.8

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.

2.9

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.

2.10

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

80960JD Datasheet(PDF) 12 Page - Intel Corporation