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Nexus Development Interface (NDI)
PXN20 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor
36-43
Reading/writing of a register then requires two (2) passes through the data-scan (DR) path of the
JTAG state machine (see 36.6.10.8).
1. The first pass through the DR selects the register to be accessed by providing an index
), and the direction (read/write). This is achieved by loading an 8-bit value into the
JTAG data register (DR). This register has the following format:
2. The second pass through the DR then shifts the data in or out of the JTAG port, LSB first.
a) During a read access, data is latched from the selected Nexus register when the JTAG state
machine passes through the CAPTURE-DR state.
b) During a write access, data is latched into the selected Nexus register when the JTAG state
machine passes through the UPDATE-DR state.
36.6.10 Functional Description
36.6.10.1 Debug Status Messages
Debug Status Messages report low power mode and debug status. Debug Status Messages are enabled
when Nexus 3+ is enabled. Entering/exiting Debug Mode as well as entering a Low Power Mode triggers
a Debug Status Message, indicating the value of the most significant byte in the Development Status
register. Debug status information is sent out in the following format:
36.6.10.2 Ownership Trace
This section details the ownership trace features of the module.
36.6.10.2.1
Overview
Ownership trace provides a macroscopic view, such as task flow reconstruction, when debugging software
written in a high level (or object-oriented) language. It offers the highest level of abstraction for tracking
operating system software execution. This is especially useful when the developer is not interested in
debugging at lower levels.
Nexus Register Index:
Selected from values in
Read/Write (R/W)
0 Read
1 Write
Table 36-30. Debug Status Message Format
(8 bits)
(4 bits)
(6 bits)
DS[31:24]
Source Processor
TCODE (000000)
Fixed Length = 18 bits
Nexus Register Index
(7 bits)
(1 bit)
R/W
RESET Value: 0x00
Summary of Contents for PXN2020
Page 1: ...PXN20 Microcontroller Reference Manual Devices Supported PXN2020 PXN2120 PXN20RM Rev 1 06 2011...
Page 42: ...PXN20 Microcontroller Reference Manual Rev 1 lxiv Freescale Semiconductor...
Page 64: ...Introduction PXN20 Microcontroller Reference Manual Rev 1 1 22 Freescale Semiconductor...
Page 112: ...Signal Description PXN20 Microcontroller Reference Manual Rev 1 3 44 Freescale Semiconductor...
Page 118: ...Resets PXN20 Microcontroller Reference Manual Rev 1 4 6 Freescale Semiconductor...
Page 372: ...e200z6 Core Z6 PXN20 Microcontroller Reference Manual Rev 1 13 8 Freescale Semiconductor...
Page 412: ...e200z0 Core Z0 PXN20 Microcontroller Reference Manual Rev 1 14 14 Freescale Semiconductor...
Page 821: ...Media Local Bus MLB PXN20 Microcontroller Reference Manual Rev 1 Freescale Semiconductor 27 49...
Page 822: ...Media Local Bus MLB PXN20 Microcontroller Reference Manual Rev 1 27 50 Freescale Semiconductor...
Page 1376: ...Memory Map PXN20 Microcontroller Reference Manual Rev 1 A 118 Freescale Semiconductor...