Motorola DSP56305 User Manual page 97

Signal
Type
Name
DE Input/
Output
MOTOROLA
Table 2-15 JTAG/OnCE Interface (Continued)
State
During
Reset
Input
DSP56305 User's Manual
Signal/Connection Descriptions
Signal Description
Debug Event—DE is an open-drain
bidirectional active-low signal. As an input, it
provides a means of entering the Debug mode
of operation from an external command
controller. As an output, it provides a means of
acknowledging that the chip has entered the
Debug mode. When asserted as an input, DE
causes the DSP56300 core to finish the current
instruction being executed, save the instruction
pipeline information, enter the Debug mode,
and wait for commands to be entered from the
debug serial input line. This signal is asserted
as an output for 3 clock cycles when the chip
enters the 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 Test
Access Port (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 the Debug mode. All other interface
with the OnCE module must occur through the
JTAG port.
This input is 5 V tolerant.
JTAG/OnCE Interface
2-39