Datasheet

UART (universal asynchronous receive transmit) RM0352
128/138 DocID024647 Rev 1
Note: To enable transmission, the TXE bit and UARTEN bit must be set to 1. Similarly, to enable
reception, the RXE bit and UARTEN bit, must be set to 1.
10 DTR
Data transmit ready. This bit is the complement of the UART data transmit ready, nUARTDTR,
modem status output. That is, when the bit is programmed to 1 then nUARTDTR is LOW.
9 RXE Receive enable. If this bit is set to 1, the receive section of the UART is enabled. Data reception
occurs for either UART signals or SIR signals depending on the setting of the SIREN bit. When
the UART is disabled in the middle of reception, it completes the current character before
stopping.
8 TXE Transmit enable. If this bit is set to 1, the transmit section of the UART is enabled. Data
transmission occurs for either UART signals, or SIR signals depending on the setting of the
SIREN bit. When the UART is disabled in the middle of transmission, it completes the current
character before stopping.
7:3 - RESERVED, do not modify, read as zero.
2 SIRLP SIR low-power IrDA mode. This bit selects the IrDA encoding mode. If this bit is cleared to 0,
low-level bits are transmitted as an active high pulse with a width of 3/16 of the bit period. If this
bit is set to 1, low-level bits are transmitted with a pulse width that is 3 times the period of the
IrLPBaud16 input signal, regardless of the selected bit rate. Setting this bit uses less power, but
might reduce transmission distances.
1 SIREN SIR enable:
0 = IrDA SIR ENDEC is disabled. nSIROUT remains LOW (no light pulse generated), and signal
transitions on SIRIN have no effect.
1 = IrDA SIR ENDEC is enabled. Data is transmitted and received on nSIROUT and SIRIN.
UARTTXD remains HIGH, in the marking state. Signal transitions on UARTRXD or modem
status inputs have no effect.
This bit has no effect if the UARTEN bit disables the UART.
0 UARTEN UART enable:
0 = UART is disabled. If the UART is disabled in the middle of transmission or reception, it
completes the current character before stopping.
1 = the UART is enabled. Data transmission and reception occurs for either UART signals or SIR
signals depending on the setting of the SIREN bit.
Table 125. UARTCR register (continued)
Bits Name Function