82551QM Datasheet, PDF (109/120 Pages) Intel Corporation – Fast Ethernet Multifunction PCI/CardBus Controller

Networking Silicon — 82551QM
13.0 82551QM Test Port Functionality
13.1
13.2
13.2.1
Introduction
The 82551QM’s XOR Tree Test Access Port (TAP) is the access point for test data to and from the
device. The port provides the ability to perform basic production level testing.
Test Function Description
The 82551QM TAP mode supports two tests that can be used in board level design. These tests
help verify basic functionality as well as test the integrity of solder connection on the board. The
tests are described in the following subsections.
Tristate
The tristate command sets all 82551QM input and output pins into a tristate (high-Z) mode (all
internal pull-ups and pull-downs are disabled). This mode is entered by setting the following test
pin combination and resetting the device:
TEST = 1
TEXEC = 0
TCK = 0
TI = 1
Datasheet
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