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Overview
MCF5272 ColdFire
®
Integrated Microprocessor User’s Manual, Rev. 3
Freescale Semiconductor
1-7
The UART can be programmed to interrupt or wake up the CPU on various normal or abnormal events.
To reduce power consumption, the UART can be disabled by software if not in use.
1.2.4
Timer Module
The timer module contains five timers arranged in two submodules. One submodule contains a
programmable software watchdog timer. The other contains four independent, identical general-purpose
timer units, each containing a free-running 16-bit timer for use in various modes, including capturing the
timer value with an external event, counting external events, or triggering an external signal or interrupting
the CPU when the timer reaches a set value. Each unit has an 8-bit prescaler for deriving the clock input
frequency from the system clock or external clock input. The output pin associated with each timer has
programmable modes.
To reduce power consumption, the timer module can be disabled by software.
1.2.5
Test Access Port
For system diagnostics and manufacturing testing, the MCF5272 includes user-accessible test logic that
complies with the IEEE 1149.1 standard for boundary scan testing, often referred to as JTAG (Joint Test
Action Group). The IEEE 1149.1 Standard provides more information.
1.3
System Design
This section presents issues to consider when designing with the MCF5272. It describes differences
between the MCF5272 (core and peripherals) and various other standard components that are replaced by
moving to an integrated device like the MCF5272.
1.3.1
System Bus Configuration
The MCF5272 has flexibility in its system bus interfacing due to the dynamic bus sizing feature in which
32-,16-, and 8-bit data bus sizes are programmable on a per-chip select basis. The programmable nature of
the strobe signals (including OE/RD, R/W, BS[3:0], and CS
n
) should ensure that external decode logic is
minimal or nonexistent. Configuration software is required upon power-on reset before chip-selected
devices can be used, except for chip select 0 (CS0), which is active after power-on reset until programmed
otherwise. BUSW1 and BUSW0 select the initial data bus width for CS0 only. A wake-up from sleep mode
or a restart from stop mode does not require reconfiguration of the chip select registers or other system
configuration registers.
1.4
MCF5272-Specific Features
This section describes features peculiar to the MCF5272.
1.4.1
Physical Layer Interface Controller (PLIC)
The physical layer interface controller (PLIC) allows the MCF5272 to connect at a physical level with
external CODECs and other peripheral devices that use either the general circuit interface (GCI), or