Power, Ground and Peripheral Signals
MOTOROLA
Pin Descriptions
2-19
Preliminary
2
Table 2-14. Clock and Phase Lock Loop Signals
Signal Name
Signal Type
Signal Description
853
Pins
854
Pins
855
Pins
857
Pins
858
Pins
EXTAL
Input
External Crystal Oscillator Input—This input
should be connected to an external crystal. If an
external clock source other than a crystal oscillator
is used, EXTAL must be tied off.
11
1
CLKO
Output
Clock Output—This pin outputs a buffered clock
signal. When enabled, this signal is the system
clock divided by four.
11
1
XTAL
Input / Output
Crystal Oscillator Output—This output connects
the internal crystal oscillator output to an external
crystal. If an external clock source other than a
crystal oscillator is used, XTAL must be used as
the input and the EXTAL connected to VDDA /2.
11
1
Table 2-15. JTAG/EOnCE Signals
Signal Name
Signal Type
Signal Description
853
Pins
854
Pins
855
Pins
857
Pins
858
Pins
TCK
Input
Test Clock Input—This input pin provides a gated
clock to synchronize the test logic and to shift
serial data to the JTAG/EOnCE port. The pin is
connected internally to a pull-down resistor.
11
1
TDI
Input
Test Data Input—This input pin provides a serial
input data stream to the JTAG/EOnCE port. It is
sampled on the rising edge of TCK and has an
on-chip pull-up resistor.
11
1
TDO
Output(Z)
Test Data Output—This tri-statable output pin
provides a serial output data stream from the
JTAG/EOnCE port. It is driven in the Shift-IR and
Shift-DR controller states, and changes on the
falling edge of TCK.
11
1
TMS
Input
Test Mode Select Input—This input pin is used to
sequence the JTAG TAP controller’s state
machine. It is sampled on the rising edge of TCK
and has an on-chip pull-up resistor.
11
1
TRST
Input
Test Reset—As an input, a low signal on this pin
provides a reset signal to the JTAG TAP controller.
To ensure complete hardware reset, TRST should
be asserted whenever RESET is asserted. The
only exception occurs in a debugging environment
when a hardware DSP reset is required and it is
necessary not to rest the JTAG/EOnCE module. In
this case, assert RESET. Do not assert TRST.
11
1
DE
Input / Output
Debug Enable—This is an open-drain,
bidirectional, active low signal. As an input, it is a
means of entering debug mode of operation from
an external command controller. As an output, it is
a means of acknowledging the chip has entered
debug mode.
11
1