Datasheet

Chapter 1. Overview 1-9
ColdFire Module Description
Figure 1-2. UART Module Block Diagram
Each UART module consists of the following major functional areas:
• Serial communication channel
• 16-bit divider for clock generation
• Internal channel control logic
• Interrupt control logic
Each UART contains an programmable clock-rate generator. Data formats can be 5, 6, 7,
or 8 bits with even, odd, or no parity, and up to 2 stop bits in 1/16 increments. The UARTs
include 4-byte and 2-byte FIFO buffers. The UART modules also provide several
error-detection and maskable-interrupt capabilities. Modem support includes
request-to-send (RTS
) and clear-to-send (CTS) lines.
BCLKO provides the time base through a programmable prescaler. The UART time scale
can also be sourced from a timer input. Full-duplex, auto-echo loopback, local loopback,
and remote loopback modes allow testing of UART connections. The programmable
UARTs can interrupt the CPU on various normal or error-condition events.
1.3.5 Timer Module
The timer module includes two general-purpose timers, each of which contains a
free-running 16-bit timer for use in any of three modes. One mode captures the timer value
with an external event. Another mode triggers an external signal or interrupts the CPU when
the timer reaches a set value, while a third mode counts external events.
The timer unit has an 8-bit prescaler that allows programming of the clock input frequency,
which is derived from the system bus cycle or an external clock input pin (TIN). The
programmable timer-output pin generates either an active-low pulse or toggles the output.
1.3.6 I
2
C Module
The I
2
C interface is a two-wire, bidirectional serial bus used for quick data exchanges
between devices. The I
2
C minimizes the interconnection between devices in the end system
and is best suited for applications that need occasional bursts of rapid communication over
Serial
Interrupt Control
Logic
CTS
RTS
RxD
TxD
or
External clock (TIN)
Internal Channel
Control Logic
Programmable
Clock
Communications
Channel
Generation
System Integration
Module (SIM)
Interrupt
Controller
UART
BCLKO
Fr
eescale S
emiconduct
or
, I
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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