Chapter 16. UART Modules
16-1
Chapter 16
UART Modules
This chapter describes the use of the universal asynchronous/synchronous
receiver/transmitters (UARTs) implemented on the MCF5272 and includes programming
examples. All references to UART refer to one of these modules.
16.1 Overview
The MCF5272 contains two independent UARTs. Each UART can be clocked by either
URT_CLK or CLKIN, eliminating the need for an external crystal. As Figure 16-1 shows,
each UART module interfaces directly to the CPU and consists of the following:
•
Serial communication channel
•
Programmable transmitter and receiver clock generation
•
Internal channel control logic
•
Interrupt control logic
Figure 16-1. Simplified Block Diagram
The serial communication channel provides a full-duplex asynchronous/synchronous
receiver and transmitter deriving an operating frequency from CLKIN or an external clock
of the correct frequency (URT_CLK). The transmitter converts parallel data from the CPU
to a serial bit stream, inserting appropriate start, stop, and parity bits. It outputs the resulting
stream on the channel transmitter serial data output (TxD). See Section 16.5.2.1,
“Transmitting.”
The receiver converts serial data from the channel receiver serial data input (RxD) to
parallel format, checks for a start, stop, and parity bits, or break conditions, and transfers
the assembled character onto the bus during read operations. The receiver may be polled-
or interrupt-driven. See Section 16.5.2.2, “Receiver.”
Serial
Interrupt Control
Logic
or
Internal Channel
Control Logic
Programmable
Clock
Communications
Channel
Generation
System Integration
Module (SIM)
Interrupt
Controller
UART
CLKIN
URT_CTS
URT_RTS
URT_RxD
URT_TxD
External clock (URT_CLK)
Содержание DigitalDNA ColdFire MCF5272
Страница 1: ...MCF5272UM D Rev 0 02 2001 MCF5272 ColdFire Integrated Microprocessor User s Manual ...
Страница 38: ...xxxviii MCF5272 User s Manual TABLES Table Number Title Page Number ...
Страница 58: ...1 10 MCF5272 User s Manual MCF5272 Specific Features ...
Страница 90: ...2 42 MCF5272 User s Manual Exception Processing Overview ...
Страница 96: ...3 6 MCF5272 User s Manual MAC Instruction Execution Timings ...
Страница 158: ...5 46 MCF5272 User s Manual Motorola Recommended BDM Pinout ...
Страница 184: ...7 12 MCF5272 User s Manual Interrupt Controller Registers ...
Страница 338: ...13 44 MCF5272 User s Manual Application Examples ...
Страница 414: ...18 6 MCF5272 User s Manual PWM Programming Model ...
Страница 452: ...19 38 MCF5272 User s Manual Power Supply Pins ...
Страница 482: ...20 30 MCF5272 User s Manual Reset Operation ...
Страница 492: ...21 10 MCF5272 User s Manual Non IEEE 1149 1 Operation ...
Страница 548: ...INDEX Index 12 MCF5272 User s Manual ...