5-2
MCF5307 User’s Manual
Signal Description
The Version 2 ColdFire core implemented the original debug architecture, now called
Revision A. Based on feedback from customers and third-party developers, enhancements
have been added to succeeding generations of ColdFire cores. The Version 3 core
implements Revision B of the debug architecture, providing more exibility for conguring
the hardware breakpoint trigger registers and removing the restrictions involving
concurrent BDM processing while hardware breakpoint registers are active.
5.2 Signal Description
Table 5-1 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
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. Maximum frequency is 1/5 the processor CLK 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 reected on processor status/debug
data signals (PST[3:0]) as the value 0xF. If CSR[BKD] is set (disabling normal BKPT
functionality), asserting BKPT generates a debug interrupt exception in the processor.
Processor Status
Clock (PSTCLK)
Delayed version of the processor clock. Its rising edge appears in the center of valid PST and
DDATA output. See
Figure 5-2. PSTCLK indicates when the development system should
sample PST and DDATA values.
If real-time trace is not used, setting CSR[PCD] keeps PSTCLK, PST and DDATA outputs from
toggling without disabling triggers. Non-quiescent operation can be reenabled by clearing
CSR[PCD], although the emulator must resynchronize with the PST and DDATA outputs.
PSTCLK starts clocking only when the rst non-zero PST value (0xC, 0xD, or 0xF) occurs
Debug Data
(DDATA[3:0])
These output signals display the hardware 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.
Table 5-2 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.
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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