PXN20RM Datasheet, PDF (1157/1376 Pages) Freescale Semiconductor, Inc – PXN20 Microcontroller

Name
JCOMP
TCK
TDI
TDO
TMS
Nexus Development Interface (NDI)
Table 36-1. Signal Properties (continued)
Port
JTAG
JTAG
JTAG
JTAG
JTAG
Function
JTAG Compliancy and TAP Sharing Control
Test Clock Input
Test Data Input
Test Data Output
Test Mode Select Input
Refer to Chapter 3, Signal Description, and Table 3-1 for detailed signal descriptions.
36.4 Memory Map and Registers
The NDI block contains no memory mapped registers. Nexus registers are accessed by the development
tool via the JTAG port using a client select and a register index. The client select is controlled by loading
the correct access instruction into the JTAG controller, as described in Section 35.4.4, JTAGC Instructions.
After the desired client TAP is selected, OnCE registers for that client are accessible by loading the
appropriate value in the RS[0:6] field of the OnCE command register (OCMD), as described in
Section 35.5.3.1, OnCE Command Register (OCMD). Nexus is enabled, and the associated Nexus
registers become accessible, by loading the NEXUS_ENABLE instruction into the RS[0:6] field of the
OCMD. When Nexus register access is enabled, the desired Nexus register is accessible using the index
shown in Table 36-3.
Detailed sequences for Nexus3+ register access are described in Section 36.6.10.8, IEEE 1149.1 (JTAG)
RD/WR Sequences. Detailed sequences for Nexus2+ register access are described in Section 36.7.9.7,
IEEE 1149.1 (JTAG) RD/WR Sequences.
Table 36-2. Nexus Client JTAG Instructions
Instruction
Description
Opcode
NPC JTAG Instruction Opcodes
NEXUS_ENABLE
Opcode for NPC Nexus Enable instruction (4-bits)
BYPASS
Opcode for the NPC BYPASS instruction (4-bits)
e200z6 OnCE JTAG Instruction Opcodes¹
NEXUS3_ACCESS
Opcode for e200z6 OnCE Nexus Enable instruction (10-bits)
BYPASS
Opcode for the e200z6 OnCE BYPASS instruction (10-bits)
e200z0 OnCE JTAG Instruction Opcodes²
NEXUS2_ACCESS
Opcode for e200z0 OnCE Nexus Enable instruction (10-bits)
BYPASS
Opcode for the e200z0 OnCE BYPASS instruction (10-bits)
1 _{Refer to the e200z6 Reference Manual for a complete list of available OnCE instructions.}
2 _{Refer to the e200z0 Reference Manual for a complete list of available OnCE instructions.}
0x0
0xF
0x7C
0x7F
0x7C
0x7F
Freescale Semiconductor
PXN20 Microcontroller Reference Manual, Rev. 1
36-7