PXS20RM Datasheet, PDF (947/1368 Pages) Freescale Semiconductor, Inc – PXS20 Microcontroller

JTAG Controller (JTAGC)
TCK when the TAP controller state machine is in the Update-DR state. Once the
ENABLE_CENSOR_CTRL instruction is executed, the register value will remain valid until a JTAG reset
occurs.
*¹
...
2
1
0
R
W
CENSOR_CTRL
Reset: *²
*
*
*
*
NOTES:
1 _{The size of CENSOR_CTRL is 65 bits .}
2 _{The reset value of CENSOR_CTRL is 65’b0 .}
Figure 29-5. CENSOR_CTRL Register
CENSOR_CTRL - Censorship Control
The CENSOR_CTRL bits are used to control chiptop censorship functions.
29.3.1.6 Boundary Scan Register
The boundary scan register is connected between TDI and TDO when the EXTEST, SAMPLE or
SAMPLE/PRELOAD instructions are active. It is used to capture input pin data, force fixed values on
output pins, and select a logic value and direction for bidirectional pins. Each bit of the boundary scan
register represents a separate boundary scan register cell, as described in the IEEE 1149.1-2001 standard
and discussed in Section 29.4.5, Boundary Scan. The size of the boundary scan register and bit ordering is
device-dependent and can be found in the device BSDL file.
29.4 Functional Description
29.4.1 JTAGC Reset Configuration
While in reset, the TAP controller is forced into the Test-Logic-Reset state, thus disabling the test logic
and allowing normal operation of the on-chip system logic. In addition, the instruction register is loaded
with the IDCODE instruction.
29.4.2 IEEE 1149.1-2001 (JTAG) Test Access Port
The JTAGC block uses the IEEE 1149.1-2001 TAP for accessing registers. This port can be shared with
other TAP controllers on the MCU. Ownership of the port is determined by the value of the JCOMP signal
and the currently loaded instruction. For more detail on TAP sharing via JTAGC instructions refer to
Section 29.4.4.6, ACCESS_AUX_TAP_x Instructions.
Data is shifted between TDI and TDO though the selected register starting with the least significant bit, as
illustrated in Figure 29-6. This applies for the instruction register, test data registers, and the bypass
register.
Freescale Semiconductor
PXS20 Microcontroller Reference Manual, Rev. 1
29-7