Motorola DSP56309 User Manual page 84

Signal
Name
DE Input/
Output
MOTOROLA
Table 2-16 OnCE/JTAG Interface (Continued)
State
Type During
Reset
Input
DSP56309UM/D
Signal/Connection Descriptions
Signal Description
Debug EventÑDE is an open-drain,
bidirectional, active-low signal providing, as
an input, a means of entering debug mode of
operation from an external command
controller, and as an output, a means of
acknowledging that the chip has entered
debug mode. This signal, when asserted as
an input, causes the DSP56300 core to finish
the current instruction being executed, save
the instruction pipeline information, enter
debug mode, and wait for commands to be
entered from the debug serial input line. This
signal is asserted as an output for three clock
cycles when the chip enters debug mode as a
result of a debug request or as a result of
meeting a breakpoint condition. The DE has
an internal pull-up resistor.
This is not a standard part of the JTAG TAP
controller. The signal connects directly to the
OnCE module to initiate debug mode
directly or to provide a direct external
indication that the chip has entered debug
mode. All other interfacing with the OnCE
module must occur through the JTAG port.
OnCE/JTAG Interface
2-37