Chip Configuration Module (CCM)
MCF52235 ColdFire® Integrated Microcontroller Reference Manual, Rev. 6
12-2
Freescale Semiconductor
12.2
External Signal Descriptions
provides an overview of the CCM signals.
12.2.1
RCON
If the external RCON pin is asserted during reset, then various chip functions, including the reset
configuration pin functions after reset, are configured according to the levels driven onto the external data
pins (see
Section 12.4, “Functional Description
”). The internal configuration signals are driven to reflect
the levels on the external configuration pins to allow for module configuration.
12.3
Memory Map/Register Definition
This subsection provides a description of the memory map and registers.
12.3.1
Programming Model
The CCM programming model consists of these registers:
•
The chip configuration register (CCR) controls the main chip configuration.
•
The reset configuration register (RCON) indicates the default chip configuration.
•
The chip identification register (CIR) contains a unique part number.
Some control register bits are implemented as write-once bits. These bits are always readable, but after the
bit has been written, additional writes have no effect, except during debug and test operations.
Some write-once bits can be read and written while in debug mode. When debug mode is exited, the chip
configuration module resumes operation based on the current register values. If a write to a write-once
register bit occurs while in debug mode, the register bit remains writable on exit from debug or test mode.
shows the accessibility of write-once bits.
Table 12-1. Signal Properties
Name
Function
Reset State
RCON
Reset configuration select
Internal weak pull-up device
Table 12-2. Write-Once Bits Read/Write Accessibility
Configuration
Read/Write Access
All configurations
Read-always
Debug operation
Write-always
Because
of
an
order
from
the
United
States
International
Trade
Commission,
BGA-packaged
product
lines
and
part
numbers
indicated
here
currently
are
not
available
from
Freescale
for
import
or
sale
in
the
United
States
prior
to
September
2010:MCF52234CVM60,
MCF52235CVM60
