NXP Semiconductors MPC5566 - Chapter 25; Reduced-Port Mode

Nexus
MPC5566 Microcontroller Reference Manual, Rev. 2
Freescale Semiconductor 25-5
25.1.3.3 Reduced-Port Mode
In reduced-port mode, a subset of the available MDO pins are used to transmit messages. All trace features
are enabled or can be enabled by writing the configuration registers via the JTAG port. The number of
MDO pins available is 4. Unused MDO (MDO[11:4]) pins can be used as GPIO. Details on GPIO
functionality configuration can be found in Chapter 6, “System Integration Unit (SIU).”
25.1.3.4 Disabled-Port Mode
In disabled-port mode, message transmission is disabled. Any debug feature that generates messages can
not be used. The primary features available are class 1 features and read/write access.
25.1.3.5 Censored Mode
When the device is in censored mode, reading the contents of internal flash externally is not allowed. To
prevent Nexus modules from violating censorship, the NPC is held in reset when in censored mode,
asynchronously holding all other Nexus modules in reset as well. This prevents Nexus read/write to
memory mapped resources and the transmission of Nexus trace messages. Refer to Table 13-17 for
information on Nexus port enabling and disabling regarding censorship.
25.2 External Signal Description
The auxiliary and JTAG pin interfaces provide for the transmission of messages from Nexus modules to
the external development tools and for access to Nexus client registers. The auxiliary/JTAG pin definitions
are outlined in Table 25-1.
Table 25-1. Signal Properties
Signal Name Port Function Reset State
EVTO Auxiliary Event out pin Negated
EVTI Auxiliary Event in pin Pullup
MCKO Auxiliary Message clock out pin (from NPC) Enabled
MDO[3:0] or
MDO[11:0]
Auxiliary Message data out pins Driven Low
1
1
Following a power-on reset, MDO[0] remains asserted until power-on reset is exited and the system
clock achieves lock.
MSEO
[1:0] Auxiliary Message start/end out pins Negated
RDY Auxiliary Ready out pin Negated
JCOMP JTAG JTAG compliancy and TAP sharing control Pulldown
TCK JTAG Test clock input Pulldown
TDI JTAG Test data input Pullup
TDO JTAG Test data output Pullup
TMS JTAG Test mode select input Pullup