FIFO management
FIFO Transmit
FIFO Receive
FIFO
Transmit
interrupt
generation
FIFO
Transmit
DMA request
generation
FIFO Receive
interrupt
generation
FIFO
Receive
DMA request
generation
Mode selection
UARTi.MDR1[2:0]
MODESELECT
UART mode
IrDA mode
CIR mode
UART interrupt
management
IrDA interrupt
management
CIR interrupt
management
UART pins
IrDA pins
CIR pins
Clock
generation
DATA
formatting
Interrupt
management
CIR clock
generation
CIR data
formatting
SIR/MIR/FIR
data formatting
IrDA (SIR/MIR/
FIR) clock
generation
UART clock
generation
UART data
formatting
UARTi_DMA_RX
UARTi_DMA_TX
UARTi_IRQ
L
4
in
te
rc
o
n
n
e
c
t
uart-022
Functional Description
Figure 19-3. UART/IrDA/CIR Functional Specification Block Diagram
19.3.2 Clock Configuration
Each UART uses a 48-MHz functional clock for its logic and to generate external interface signals. Each
UART uses an interface clock for register accesses. The PRCM module generates and controls all these
clocks (for more information, see Clock Domain Module Attributes, in
, Power, Reset, and Clock
Management).
The idle and wake-up processes use a handshake protocol between the PRCM and the UART (for a
description of the protocol, see Module-Level Clock Management in
, Power, Reset, and Clock
Management). The UARTi.UART_SYSC[4:3] IDLEMODE bit field controls UART idle mode.
19.3.3 Software Reset
The UARTi.UART_SYSC[1] SOFTRESET bit controls the software reset; setting this bit to 1 triggers a
software reset functionally equivalent to hardware reset.
19.3.4 Power Management
19.3.4.1 UART Mode Power Management
19.3.4.1.1 Module Power Saving
In UART modes, sleep mode is enabled by setting the UARTi.UART_IER[4] SLEEP_MODE bit to 1 (when
the UARTi.UART_EFR[4] ENHANCED_EN bit is set to 1).
Sleep mode is entered when all the following conditions exist:
•
The serial data input line, uarti_rx, is idle.
•
The TX FIFO and TX shift register are empty.
•
The RX FIFO is empty.
•
The only pending interrupts are THR interrupts.
3454
Universal Asynchronous Receiver/Transmitter (UART)
SPRUH73H – October 2011 – Revised April 2013
Copyright © 2011–2013, Texas Instruments Incorporated