Motorola MPC8260 User Manual
MOTOROLA
Chapter 12. IEEE 1149.1 Test Access Port
12-3
Part III. The Hardware Interface
Figure 12-2. TAP Controller State Machine
12.3 Boundary Scan Register
The MPC8260Õs scan chain implementation has a 475-bit boundary scan register that
contains bits for all device signal, clock pins, and associated control signals. The XTAL,
EXTAL, and XFC pins are associated with analog signals and are not included in the
boundary scan register. An IEEE-1149.1-compliant boundary-scan register has been
included on the MPC8260 that can be connected between TDI and TDO when EXTEST or
SAMPLE/PRELOAD instructions are selected. It is used for capturing signal pin data on
the input pins, forcing Þxed values on the output signal pins, and selecting the direction and
drive characteristics (a logic value or high impedance) of the bidirectional and three-state
signal pins. Figure 12-3, Figure 12-4, Figure 12-5, and Figure 12-6 show various cell types.
contains bits for all device signal, clock pins, and associated control signals. The XTAL,
EXTAL, and XFC pins are associated with analog signals and are not included in the
boundary scan register. An IEEE-1149.1-compliant boundary-scan register has been
included on the MPC8260 that can be connected between TDI and TDO when EXTEST or
SAMPLE/PRELOAD instructions are selected. It is used for capturing signal pin data on
the input pins, forcing Þxed values on the output signal pins, and selecting the direction and
drive characteristics (a logic value or high impedance) of the bidirectional and three-state
signal pins. Figure 12-3, Figure 12-4, Figure 12-5, and Figure 12-6 show various cell types.
Test Logic
Reset
RunÑTest/Idle
SelectÑDR_SCAN
CaptureÑDR
ShiftÑDR
Exit1ÑDR
PauseÑDR
Exit2ÑDR
UpdateÑDR
SelectÑIR_SCAN
CaptureÑIR
ShiftÑIR
Exit1ÑIR
PauseÑIR
Exit2ÑIR
UpdateÑIR
0
0
0
0
1
1
1
0
0
0
0
1
1
1
1
1
0
0
1
1
1
1