PXR40RM Datasheet, PDF (118/1434 Pages) Freescale Semiconductor, Inc – PXR40 Microcontroller

Signal Descriptions
Signal Name
XTAL
EXTAL
D_CLKOUT
ENGCLK
Table 3-14. Reset and Clock Signals (continued)
Description
XTAL is the output pin for an external crystal oscillator.
EXTAL is the input pin for an external crystal oscillator or an external clock source.
CLKOUT is the device system clock output (for the development EBI).
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.
3.3.11 JTAG and Nexus Signals
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
MDO0_GPIO220¹
MDO[3:1]_GPIO[223:221]¹
MDO[11:4]_GPIO[82:75]¹
MCKO is a free running clock output to the development tools which is used for timing of
the MDO and MSEO signals.
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] 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] 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.
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.
3-52
PXR40 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor