AS91L1006BU
July 2004
6-Port JTAG Gateway
Description
The AS91L1006BU is a one to 6-port
JTAG gateway. It partitions a single JTAG chain
into six separate chains. These separate chains
can be optionally configured to operate as a single
chain.
The AS91L1006BU device is used to
provide enhanced capabilities to the standard
IEEE1149.1. It enables the IEEE1149.1 interface
to be used in a true Multi-Drop environment without
any additional signals. This Multi-Drop capability
enables the standard IEEE1149.1 interface to be
used not just for stand alone PCB (Printed Circuit
Board) testing, but also for complete system
testing including all PCBs within a system back
plane environment.
The AS91L1006BU provides the capability
of partitioning the PCB, into multiple smaller
IEEE1149.1 scan chains totally under software
control. Partitioning the IEEE1149.1 chains on the
PCB has several benefits which include easier
fault diagnostics capabilities as a fault on one of
the IEEE1149.1 Local Scan Ports (LSPs) does
not render the PCB untestable, faster flash
programming on the PCBs, and removal of
IEEE1149.1 signal loading issues.
All
of
the
protocols
required
for
addressing the AS91L1006BU device via the
Multi-Drop
capability
and
the
protocols
for
configuring which of the six IEEE1149.1 LSPs on
the AS91L1006BU are to be used, is handled via
3
rd party ATPG tools from vendors like Asset-
Intertech and JTAG Technologies. In a Multi-Drop
environment
it
is
also
possible
to
perform
interconnect tests between multiple PCBs within a
system thus extending the interconnect tests to
the back plane itself.
Key Features
Device Multi-Drop addressable via the IEEE
1149.1 protocol
Support for 6 local scan chains addressable via
the IEEE 1149.1 interface
Support for Pass-Through
™
Support
for
the
IEEE
1149.1
USERCODE
instruction
Support for Status instruction enabling non-
intrusive monitoring of the system card
Local Scan Port (LSP) enable signal provides the
ability to use non IEEE 1149.1 compliant devices
that require JTAG enable signal
Provides the ability to initiate Self-Test on a
remote PCB via a standard IEEE 1149.1
command
Support for JTAG Technologies AutoWR
™
feature
Pinout and feature set compatible (complete
second source) with the Firecron JTS06BU
device
Available in a 100-pin LQFP or a 100-pin
FPBGA lead free package
Device Block Diagram
D e vice
S e le c t io n
Logic
Loc al S c an P o r t
P a r k / U n- par k
S y nc Logic
114 9 . 1 T A P C o nt r o ller
and
B o undar y R e g is t er S e le c t io n Log ic
P a ss T h r o u g h
Logic & Loc al
Sc a n Po r t
C onnec t ion/
Co n f ig
lo g ic
LS P 1
LS P 2
LS P 3
LS P 4
LS P 5
LS P 6
S t a t u s D a ta
Us e r c o d e
Da t a
De v ic e
ad dr e s s
P a s s T h r ough E nable
P r im ar y 1 149. 1
J T A G In te r f a c e
Figure 1 - AS91L1006BU Device Block Diagram
Alliance Semiconductor
2575 Augustine Drive
• Santa Clara, CA 95054 • T: 408-855-4900 • F: 408-855-4999 • www.alsc.com