Motorola DSP56009 User Manual page 61

Table 2-12 On-Chip Emulation Port Signals (Continued)
Signal Signal
Name Type
DSCK Input
OS1 Output
MOTOROLA
State
during
Reset
Output, Debug Serial Clock (DSCK)—The DSCK/OS1
Driven signal, when an input, is the signal through which
Low the serial clock is supplied to the OnCE port. The
serial clock provides pulses required to shift data
into and out of the OnCE port. Data is clocked into
the OnCE port on the falling edge and is clocked
out of the OnCE port on the rising edge.
Operating Status 1 (OS1)—If the OS1 signal is an
output and used in conjunction with the OS0
signal, it provides information about the DSP
status when the DSP is not in the Debug mode. The
debug serial clock frequency must be no greater
than 1/8 of the processor clock frequency. The
signal is tri-stated when it is changing from input
to output.
Note: If the OnCE port is in use, an external
pull-down resistor should be attached to the
DSCK/OS1 pin. If the OnCE port is not in use,
the resistor is not required.
DSP56009 User's Manual
Signal Descriptions
On-Chip Emulation (OnCE
Signal Description
TM
) Port
2-23