IEEE 1149.1-Compliant Interface (JTAG)
MPC561/MPC563 Reference Manual, Rev. 1.2
Freescale Semiconductor
25-31
During the capture-IR controller state, the parallel inputs to the instruction shift register are loaded with
the CLAMP command code.
25.1.3.1
EXTEST
The external test (EXTEST) instruction selects the 520-bit boundary scan register. EXTEST also asserts
internal reset for the MPC561/MPC563 system logic to force a predictable beginning internal state while
performing external boundary scan operations.
By using the TAP, the register is capable of:
a) scanning user-defined values into the output buffers
b) capturing values presented to input pins
c) controlling the output drive of three-state output or bidirectional pins
25.1.3.2
SAMPLE/PRELOAD
The SAMPLE/PRELOAD instruction initializes the boundary scan register output cells prior to selection
of EXTEST. This initialization ensures that known data will appear on the outputs when entering the
EXTEST instruction. The SAMPLE/PRELOAD instruction also provides a means to obtain a snapshot of
system data and control signals.
NOTE
Since there is no internal synchronization between the scan chain clock
(TCK) and the system clock (CLKOUT), there must be provision of some
form of external synchronization to achieve meaningful results.
25.1.3.3
BYPASS
The BYPASS instruction selects the single-bit bypass register as shown in
. This creates a shift
register path from TDI to the bypass register and, finally, to TDO, circumventing the 520-bit boundary
scan register. This instruction is used to enhance test efficiency when a component other than the
MPC561/MPC563 becomes the device under test.
Figure 25-5. Bypass Register
When the bypass register is selected by the current instruction, the shift register stage is set to a logic zero
on the rising edge of TCK in the capture-DR controller state. Therefore, the first bit to be shifted out after
selecting the bypass register will always be a logic zero.
1
1
Mux
G1
C
D
TO TDO
FROM TDI
0
SHIFT DR
CLOCK DR
Summary of Contents for MPC561
Page 84: ...MPC561 MPC563 Reference Manual Rev 1 2 lxxxiv Freescale Semiconductor...
Page 144: ...Signal Descriptions MPC561 MPC563 Reference Manual Rev 1 2 2 46 Freescale Semiconductor...
Page 206: ...Central Processing Unit MPC561 MPC563 Reference Manual Rev 1 2 3 62 Freescale Semiconductor...
Page 302: ...Reset MPC561 MPC563 Reference Manual Rev 1 2 7 14 Freescale Semiconductor...
Page 854: ...Time Processor Unit 3 MPC561 MPC563 Reference Manual Rev 1 2 19 24 Freescale Semiconductor...
Page 968: ...Development Support MPC561 MPC563 Reference Manual Rev 1 2 23 54 Freescale Semiconductor...
Page 1144: ...Internal Memory Map MPC561 MPC563 Reference Manual Rev 1 2 B 34 Freescale Semiconductor...
Page 1212: ...TPU3 ROM Functions MPC561 MPC563 Reference Manual Rev 1 2 D 60 Freescale Semiconductor...
Page 1216: ...Memory Access Timing MPC561 MPC563 Reference Manual Rev 1 2 E 4 Freescale Semiconductor...