Idcode Instruction; Sample/Preload Instruction - NXP Semiconductors freescale KV4 Series Reference Manual

Functional description
Instruction
ARM JTAG-DP Reserved
CLAMP
ARM JTAG-DP Reserved
BYPASS

48.4.4.1 IDCODE instruction

IDCODE selects the 32-bit device identification register as the shift path between TDI
and TDO. This instruction allows interrogation of the MCU to determine its version
number and other part identification data. IDCODE is the instruction placed into the
instruction register when the JTAGC block is reset.

48.4.4.2 SAMPLE/PRELOAD instruction

The SAMPLE/PRELOAD instruction has two functions:
• The SAMPLE portion of the instruction obtains a sample of the system data and
control signals present at the MCU input pins and just before the boundary scan
register cells at the output pins. This sampling occurs on the rising edge of TCK in
the Capture-DR state when the SAMPLE/PRELOAD instruction is active. The
sampled data is viewed by shifting it through the boundary scan register to the TDO
output during the Shift-DR state. Both the data capture and the shift operation are
transparent to system operation.
• The PRELOAD portion of the instruction initializes the boundary scan register cells
before selecting the EXTEST or CLAMP instructions to perform boundary scan
tests. This is achieved by shifting in initialization data to the boundary scan register
during the Shift-DR state. The initialization data is transferred to the parallel outputs
of the boundary scan register cells on the falling edge of TCK in the Update-DR
state. The data is applied to the external output pins by the EXTEST or CLAMP
instruction. System operation is not affected.
1346
Table 48-3. 4-bit JTAG instructions (continued)
Code[3:0]
1011
1100
1110
1111
KV4x Reference Manual, Rev. 2, 02/2015
Preliminary
Instruction summary
This instruction goes the ARM JTAG-DP controller. See the
ARM JTAG-DP documentation for more information.
Selects bypass register and applies preloaded values to
output pins.
NOTE: Execution of this instruction asserts functional reset.
This instruction goes the ARM JTAG-DP controller. See the
ARM JTAG-DP documentation for more information.
Selects bypass register for data operations
Freescale Semiconductor, Inc.