PXN20RM Datasheet, PDF (1256/1376 Pages) Freescale Semiconductor, Inc – PXN20 Microcontroller

Nexus Development Interface (NDI)
By default, after power-on reset, N2+/3 circuitry (controller) and the dedicated pad are disabled to avoid
power consumption. It can only be enabled via a certain sequence given by the debugger. As soon as the
N2+/3 port is enabled even the N2+/3 pads are enabled.
36.11 Debug Methods
This section describes the debug methods for the available packages for the PXN20. The Nexus1 debug
method applies to the 208MAPBGA, while the Nexus2+/3 applies to and is available only with the
256MAPBGA package.
36.11.1 208 MAPBGA Package Debug Method
The 208MAPBGA package provides only the Nexus class 1 debug method, based on IEEE1149.1
standard. Figure 36-82 shows an example.
208 MAPBGA production package
JTAG Connector
3-wire
cable
Development
Tool
Customer application board
Figure 36-82. Nexus Class 1 Debugging Method Using JTAG Pins
36.11.2 256 MAPBGA Package Debug Method
The 256MAPBGA package provide allows the Nexus Class 2+/3 debug method as shown in Figure 36-83.
Adapter board
Nexus
Connector
256 MAPBGA production package
Ribbon
cable
Development
Tool
208MAPBGA
socket/interface
Customer application board
Figure 36-83. Nexus Class 2+/3 Debugging Method Using JTAG Pins
As 3.3 V fast pads are used for the N2+/3 port, an adapter board could provide buffers between the N2+/3
pads and the connector.
36-106
PXN20 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor