
AMD-K5 Processor
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21062E/0—June 1997
AMD K86 Family BIOS and Software Tools Developers Guide
Preliminary Information
Hardware Debug Tool (HDT)
The Hardware Debug Tool (HDT)—sometimes referred to as
the debug port or Probe Mode—is a collection of signals,
registers, and processor microcode that is enabled when
external debug logic drives R/S Low or loads the processor’s
Test Access Port (TAP) instruction register with the USEHDT
instruction.
AMD-K5 Processor x86 Architecture Extensions
The AMD-K5 processor is compatible with the instruction set,
programming model, memory management mechanisms, and
other software infrastructure supported by the 486 and
Pentium (735\90, 815\100) processors. Operating system and
application software that runs on Pentium can be executed on
the AMD-K5. Because the AMD-K5 processor takes a
significantly different approach to implementing the x86
architecture, some subtle differences from Pentium may be
visible to system and code developers. These differences are
described in Appendix A of the
AMD-K5 Processor Technical
Reference Manual,
order# 18524.
Call AMD at 1-800-222-9323 to order AMD-K5 support
documents.
Before implementing the AMD-K5 processor model-specific
features, check CPUID for supported feature flags. See
“CPUID” on page 86 for more information.
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259
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INV
FERR#
IERR#
Input Cell
Output Cell
Output Cell
Table 18. Boundary Scan Register Bit Definitions (continued)
Bit
Pin Name
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