Figure 10-4. Operation Of The Pentium - Intel Pentium Pro Family Developer's Manual

(a) Capture-IR
A AAAAAAAAAAAAAAAAAAAAAAAAAAAAA
A
A A
A
A
A A
A
A A
A
A
A A
A
A
A A
A AAAA AAAA AAAA AAAA AAAA AAAA AAAA
AAAA AAAA AAAA AAAA AAAA AAAA AAAA

Figure 10-4. Operation of the Pentium

A timing diagram for loading the BYPASS instruction (op-code "111111") into the TAP is
shown in Figure 10-5. (Note that the LSB of the TAP instruction must be shifted in first.) Vertical
arrows on the figure show the specific clock edges on which the Capture-IR, Shift-IR and
Update-IR actions actually take place. Capture-IR (which pre-loads the instruction shift register
with "000001") and Shift-IR operate on rising edges of TCK, and Update-IR (which updates the
actual instruction register) takes place on the falling edge of TCK.
PENTIUM® PRO PROCESSOR TEST ACCESS PORT (TAP)
(b) Shift-IR
A AA AAAAAAAAAAAAAAAAAAAAAAAAAAAAA
A AA
A A AA AA
A AA
A AA
A A AA AA
A AA
A A AA AA
A AA
A AA
A A AA AA
A AA
A AA
A A AA AA
A A AA AAAA AAAA AAAA AAAA AAAA AAAA
A AAAA AAAA AAAA AAAA AAAA AAAA
®
Pro Processor TAP Instruction Register
(c) Update-IR
AA AA A AAAAAAAAAAAAAAAAAAAAAAAAAAAAA
A
AA A A
AA AA
A
AA A
AA A A
AA AA
A
AA A A
AA AA
A
AA A
AA A A
AA AA
A
AA A
AA A A
AA AA
AAAA AA A AAAA AAAA AAAA AAAA
AAAA AA AA AAAA AAAA AAAA AAAA
A
A
A A
A
A
A A
A
A A
A
A
A A
A
A
A A
AAAA AAAA AAAA A A
AAAA AAAA AAAA A
10-5