Modes of Operation
MCF51CN128 Reference Manual, Rev. 6
3-6
Freescale Semiconductor
Individual power states are discussed in more detail in the following sections.
3.4
Debug Mode
Debug mode functions are managed through the background debug controller (BDC) in the Version 1
ColdFire core. The BDC allows you to analyze MCU operation during software development.
The debug interface is used to write a bootloader or user application program into the flash program
memory before the MCU operates in run mode for the first time. When the MCF51CN128 is shipped from
the Freescale Semiconductor factory, the flash program memory is erased by default unless specifically
noted. So, there is no program that can be executed in run mode until the flash memory is initially
programmed. The debug interface can also be used to erase and reprogram the flash memory after it has
been previously programmed.
Chapter 20, “Version 1 ColdFire Debug (CF1_DEBUG),”
for more details regarding the debug
interface.
3.5
Secure Mode
While the MCU is in secure mode, there are severe restrictions on which debug commands can be used.
In this mode, only the upper byte of the core’s XCSR, CSR2, and CSR3 registers can be accessed. See
Chapter 20, “Version 1 ColdFire Debug (CF1_DEBUG),”
for details.
8
Stop3
Run
Interrupt when SPMSC2[LPWUI] is set
Run
Stop3
Pre-configure settings shown in
, execute
STOP instruction
9
Stop4
Halt
When a BACKGROUND command is received
through the BKGD/MS pin (XCSR[ENBDM] must
be set).
Halt
Stop4
Not supported.
10
Halt
Run
GO instruction issued via BDM
Run
Halt
When a BACKGROUND command is received
through the BKGD/MS pin OR
When a HALT instruction is executed OR
When encountering a BDM breakpoint
11
Wait
Halt
When a BACKGROUND command is received
through the BKGD/MS pin (XCSR[ENBDM] must
be set).
Halt
Wait
Not supported.
1
An analog connection from this pin to the on-chip regulator wakes the regulator, which then initiates a power-on-reset
sequence.
Table 3-3. Triggers for Transitions Shown in
Figure 3-2
(continued)
Transition #
From
To
Trigger