MPC555
/
MPC556
DEVELOPMENT SUPPORT
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
21-32
The DSDI pin is also used at reset to control the overall chip configuration mode and
to determine the development port clock mode. See section
Port Serial Communications — Clock Mode Selection
for more information.
21.5.4 Development Serial Data Out
The debug mode logic shifts data out of the development port shift register using the
development serial data out (DSDO) pin. All transitions on DSDO are synchronous
with DSCK or CLKOUT depending on the clock mode. Data will be valid a setup time
before the rising edge of the clock and will remain valid a hold time after the rising edge
of the clock.
Refer to
for DSDO data meaning.
21.5.5 Freeze Signal
The freeze indication means that the processor is in debug mode (i.e., normal proces-
sor execution of user code is frozen). On the MPC555 / MPC556, the freeze state can
be indicated by three different pins. The FRZ signal is generated synchronously with
the system clock. This indication may be used to halt any off-chip device while in de-
bug mode as well as a handshake means between the debug tool and the debug port.
The internal freeze status can also be monitored through status in the data shifted out
of the debug port.
21.5.5.1 SGPIO6/FRZ/PTR Pin
The SGPIO6/FRZ/PTR pin powers up as the PTR function and its function is controlled
by the GPC bits in the SIUMCR.
21.5.5.2 IWP[0:1]/VFLS[0:1] Pins
The IWP[0:1]/VFLS[0:1] pins power up as the VFLS[0:1] function and their function
can be changed via the DBGC bits in the SIUMCR (see
). They can also be set via the reset configuration word (See
Hard Reset Configuration Word)
. The FRZ state is indicated by the value b11 on the
VFLS[0:1] pins.
21.5.5.3 VFLS[0:1]_MPIO32B[3:4] Pins
The VFLS[0:1]_MPIO32B[3:4] Pins power up as the MPIO32B[3:4] function and their
function can be changed via the VFLS bit in the MIOS1TPCR register (see section
15.15.1.1). The FRZ state is indicated by the value b11 on the VFLS[0:1] pins.
21.5.6 Development Port Registers
The development port consists logically of the three registers: development port in-
struction register (DPIR), development port data register (DPDR), and trap enable
control register (TECR). These registers are physically implemented as two registers,
development port shift register and trap enable control register. The development port
shift register acts as both the DPIR and DPDR depending on the operation being per-
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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