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Debug Support
MCF5272 ColdFire
®
Integrated Microprocessor User’s Manual, Rev. 3
5-2
Freescale Semiconductor
5.2
Signal Description
describes debug module signals. All ColdFire debug signals are unidirectional and related to a
rising edge of the processor core’s clock signal. The standard 26-pin debug connector is shown in
Section 5.8, “Freescale-Recommended BDM Pinout
shows PSTCLK timing with respect to PST and DDATA.
Figure 5-2. PSTCLK Timing
Table 5-1. Debug Module Signals
Signal
Description
Development Serial
Clock (DSCLK)
Internally synchronized input. (The logic level on DSCLK is validated if it has the same value on two
consecutive rising CLKIN edges.) Clocks the serial communication port to the debug module during
packet transfers. Maximum frequency is 1/5 the processor status clock (PSTCLK) speed. At the
synchronized rising edge of DSCLK, the data input on DSI is sampled and DSO changes state.
Development Serial
Input (DSI)
Internally synchronized input that provides data input for the serial communication port to the debug
module.
Development Serial
Output (DSO)
Provides serial output communication for debug module responses. DSO is registered internally.
Breakpoint (BKPT)
Input used to request a manual breakpoint. Assertion of BKPT puts the processor into a halted state
after the current instruction completes. Halt status is reflected on processor status signals (PST[3:0]) as
the value 0xF.
Processor Status
Clock (PSTCLK)
Delayed version of the processor clock. Its rising edge appears in the center of valid PST and DDATA
output. See
. PSTCLK indicates when the development system should sample PST and
DDATA values.
Debug Data
(DDATA[3:0])
These output signals display the register breakpoint status as a default, or optionally, captured address
and operand values. The capturing of data values is controlled by the setting of the CSR. Additionally,
execution of the WDDATA instruction by the processor captures operands which are displayed on
DDATA. These signals are updated each processor cycle.
Processor Status
(PST[3:0])
These output signals report the processor status.
shows the encoding of these signals. These
outputs indicate the current status of the processor pipeline and, as a result, are not related to the
current bus transfer. The PST value is updated each processor cycle.
PSTCLK
PST
or
DDATA