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Freescale Semiconductor
32-1
Chapter 32
UART Modules
32.1
Introduction
This chapter describes the use of the three universal asynchronous receiver/transmitters (UARTs) and
includes programming examples.
NOTE
The designation
n
appears throughout this section to refer to registers or
signals associated with one of the three identical UART modules: UART0,
UART1, or UART2.
32.1.1
Overview
The internal bus clock can clock each of the three independent UARTs, eliminating the need for an external
UART clock. As
shows, each UART module interfaces directly to the CPU and consists of:
•
Serial communication channel
•
Programmable clock generation
•
Interrupt control logic and DMA request logic
•
Internal channel control logic
Figure 32-1. UART Block Diagram
Serial
Interrupt Control
Logic
Internal Channel
Control Logic
Programmable
Clock
Communications
Channel
Generation
UART
Internal Bus Clock (f
sys/2
)
or External Clock (DT
n
IN)
DMA Request
Logic
Transmit DMA Request
Receive DMA Request
Interrupt Request
(to Interrupt Controller)
(To DMA Controller)
External
Si
gnal
s
UART Registers
U
n
CTS
U
n
RTS
U
n
RXD
U
n
TXD
Internal Bus
Summary of Contents for MCF54455
Page 33: ...xxviii Freescale Semiconductor ...
Page 67: ...Freescale Semiconductor 1 ...
Page 125: ...Freescale Semiconductor 1 ...
Page 145: ...Enhanced Multiply Accumulate Unit EMAC 5 21 Freescale Semiconductor ...
Page 173: ...Cache 6 28 Freescale Semiconductor ...
Page 179: ...Static RAM SRAM 7 6 Freescale Semiconductor ...
Page 207: ...Power Management 9 16 Freescale Semiconductor ...
Page 323: ...Reset Controller Module 13 8 Freescale Semiconductor ...
Page 389: ...Pin Multiplexing and Control 16 44 Freescale Semiconductor ...
Page 575: ...PCI Bus Controller 22 58 Freescale Semiconductor ...
Page 600: ...Advanced Technology Attachment ATA Freescale Semiconductor 23 25 ...
Page 601: ...Freescale Semiconductor 1 ...
Page 842: ...I2 C Interface Freescale Semiconductor 33 16 ...
Page 843: ...Freescale Semiconductor 1 ...
Page 921: ...Revision History A 6 Freescale Semiconductor ...