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UART/IrDA/CIR Functional Description
An interrupt can be generated on a wake-up event by setting the UARTi.
[4] RX_CTS_WU_EN
bit to 1. See
, Wake-Up Interrupt, to understand how to manage the interrupt.
NOTE:
There must be no writing to the divisor latches, UARTi.
and UARTi.
, to
set the baud clock, BCLK, while in sleep mode. It is advisable to disable sleep mode using
the UARTi.
[4] SLEEP_MODE bit before writing to the UARTi.
register or
the UARTi.
register.
19.4.5.1.2 System Power Saving
Sleep and auto-idle modes are embedded power-saving features. At the system level, power-reduction
techniques can be applied by shutting down certain internal clock and power domains of the device.
The UART supports an idle req/idle ack handshaking protocol. This protocol is used at the system level to
shut down clocks of the UART in a clean and controlled manner and to switch the UART from
interrupt-generation mode to wake-up generation mode for unmasked events (see the
UARTi.
[2] ENAWAKEUP bit and the UARTi.
register).
For more information, see
, Power, Reset, and Clock Management.
19.4.5.2 IrDA Mode Power Management (UART3 Only)
19.4.5.2.1 Module Power Saving
In IrDA modes, sleep mode is enabled by setting the UART3.MDR[3] IR_SLEEP bit to 1.
Sleep mode is entered when all the following conditions exist:
•
The serial data input line, uart3.rx_irrx, is idle.
•
The TX FIFO and TX shift register are empty.
•
The RX FIFO is empty.
•
No interrupts are pending except THR interrupts.
The module wakes up when a change is detected on the uart3_rx_irrx line or when data is written to the
TX FIFO.
19.4.5.2.2 System Power Saving
System power saving for the IrDA mode has the same functionality as that for the UART mode (see
, System Power Saving).
19.4.5.3 CIR Mode Power Management (UART3 Only)
19.4.5.3.1 Module Power Saving
Module power saving for the CIR mode has the same functionality as that for the IrDA mode (see
, Module Power Saving).
19.4.5.3.2 System Power Saving
System power saving for the CIR mode has the same functionality as that for the UART mode (see
, System Power Saving).
2919
SWPU177N – December 2009 – Revised November 2010
UART/IrDA/CIR
Copyright © 2009–2010, Texas Instruments Incorporated
