Élan™SC520 Microcontroller User’s Manual 26-1
CHAPTER
26
AMDebug™ TECHNOLOGY
26.1 OVERVIEW
The ÉlanSC520 microcontroller supports a full-featured, high-performance in-circuit emu-
lation capability. This in-circuit emulation support was developed at AMD specifically to
enable users to test and debug their software earlier in the design cycle. Utilizing this
capability, the software can be more extensively exercised, and at full execution speeds.
It also allows tracing during execution from the Am5
x
86 CPU’s internal cache.
The AMDebug interface included on the ÉlanSC520 microcontroller provides the product
design team with two different communication paths, each of which is supported by powerful
debug tools from third-party vendors in AMD’s FusionE86 program. (See AMD FusionE86
partners documentation on p. iii under Third-Party Support.)
■ Serial AMDebug technology uses a serial connection based on an enhanced JTAG
protocol and an inexpensive 12-pin connector that can be placed on each board design.
This low-cost solution satisfies the requirement of a large number of software developers.
■ Parallel AMDebug technology uses a 25-pin parallel debug port to exchange commands
and data between the ÉlanSC520 microcontroller and the host. The higher pin count
requires that the extra signal pins be provided on a special bond-out package of the
ÉlanSC520 microcontroller; this package is made available only to tool developers such
as in-circuit emulator manufacturers. The parallel AMDebug port greatly simplifies the
task of supporting high-speed data exchange.
An on-chip trace controller provides trace information for reconstructing instruction execu-
tion flow in the processor. It supports tracing either to the serial AMDebug port, the bond-
out parallel port, or to an internal trace buffer.
Use of JTAG technology for conventional boundary scan testing is described in Chapter 25,
“Boundary Scan Test Interface”.
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