21
21-11
Rev.1.0
JTAG
21.4 Basic Operation of the JTAG
Figure 21.4.4 DR Path Sequence
Note: The shift operation of the data register for the shift register stage is right-shifted, therefore, the
output from JTDO is from the LSB side. Input to JTDI starts from the value to be set in LSB side.
JTCK
Select-DR-Scan
Capture-DR
Shift-DR
Exit1-DR
Update-DR
Run-T
est/Idle
Run-T
est/Idle
Don't Care
JTMS
JTDI
JTDO
Finished storing setup data in the shift
register stage of the selected data register.
Setup data is set in the parallel output stage
at fall of JTCK in "Update-DR" state.
JTDI input is sampled at rise
of JTCK in "Shift-DR" state.
TAP
state
LSB value
High impedance
MSB value
High impedance
JTDO is output at fall of
JTCK in "Shift-DR" state.