Freescale Semiconductor PXR4030, Reference Manual

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Signal Descriptions
3-52 Freescale Semiconductor
PXR40 Microcontroller Reference Manual, Rev. 1
3.3.11 JTAG and Nexus Signals
XTAL XTAL is the output pin for an external crystal oscillator.
EXTAL EXTAL is the input pin for an external crystal oscillator or an external clock source.
D_CLKOUT CLKOUT is the device system clock output (for the development EBI).
ENGCLK ENGCLK is a 50% duty cycle output clock with a maximum frequency of the device system
clock divided by two. ENGCLK is not synchronous to CLKOUT.
Table 3-15. JTAG and Nexus Signals
Signal Name Description
EVTI EVTI is an input that is read during a debug port reset to enable or disable the Nexus
Auxiliary port for data trace. After reset, the EVTI pin is used to initiate program and data
trace synchronization messages or generate a breakpoint.
EVTO EVTO is an output that provides timing to a development tool for a single watchpoint or
breakpoint occurrence. The BAM uses this pin to select if auto baud rate is on or off
(
Section 9.3.4, Serial Boot Mode ).
MCKO MCKO is a free running clock output to the development tools which is used for timing of
the MDO and MSEO signals.
MDO0_GPIO220
1
1
GPIO function for MDO[11:0] is only available on Rev.2 of the device. Do not connect pin directly to a power supply or
ground.
MDO[0] is a trace message output to the development tools. In addition, MDO[0] indicates
the lock status of the system clock following a power-on reset. There is an internal pullup
on MDO[0]. This pin functions as GPIO when Nexus messaging is disabled.
MDO[3:1]_GPIO[223:221]
1
MDO[3:1] are the trace message outputs to the development tools for reduced port mode.
These pins function as GPIO when Nexus messaging is disabled.
MDO[11:4]_GPIO[82:75]
1
MDO[11:4] are the trace message outputs to the development tools for reduced port
mode. These pins function as GPIO when Nexus messaging is disabled
MDO[15:12]_GPIO[234:231] Trace message outputs to the development tools for full port mode. These pins function
as GPIO when the Nexus Development Interface (NDI) functions in reduced port mode or
when Nexus messaging is disabled
MSEO[1:0] MSEO[1:0] are output signals that indicate when messages start and end on the MDO
pins.
RDY RDY is an output signal that indicates to the development tools the data is ready to be read
from or written to the Nexus read/write access registers.
TCK TCK provides the clock input for the on-chip test logic.
TDI TDI provides the serial test instruction and data input for the on-chip test logic.
TDO TDO provides the serial test data output for the on-chip test logic.
TMS TMS controls test mode operations for the on-chip test logic.
JCOMP JCOMP enables the JTAG TAP controller.
TEST TEST places the chip into test mode. You must tie this pin to VSS.
Table 3-14. Reset and Clock Signals (continued)
Signal Name Description