SCI Registers
1034
SPRUHE8E – October 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
C28 Serial Communications Interface (SCI)
Table 13-10. SCI Control Register 1 (SCICTL1) Field Descriptions (continued)
Bit
Field
Valu
e
Description
2
SLEEP
SCI sleep. The TXWAKE bit controls selection of the data-transmit feature, depending on which transmit
mode (idle-line or address-bit) is specified at the ADDR/IDLE MODE bit (SCICCR, bit 3). In a multiprocessor
configuration, this bit controls the receiver sleep function. Clearing this bit brings the SCI out of the sleep
mode.
The receiver still operates when the SLEEP bit is set; however, operation does not update the receiver
buffer ready bit (SCIRXST, bit 6, RXRDY) or the error status bits (SCIRXST, bit 5
−
2: BRKDT, FE, OE, and
PE) unless the address byte is detected. SLEEP is not cleared when the address byte is detected.
0
Sleep mode disabled
1
Sleep mode enabled
1
TXENA
SCI transmitter enable. Data is transmitted through the SCITXD pin only when TXENA is set. If reset,
transmission is halted but only after all data previously written to SCITXBUF has been sent.
0
Transmitter disabled0
1
Transmitter enabled
0
RXENA
SCI receiver enable. Data is received on the SCIRXD pin and is sent to the receiver shift register and then
the receiver buffers. This bit enables or disables the receiver (transfer to the buffers).
Clearing RXENA stops received characters from being transferred to the two receiver buffers and also stops
the generation of receiver interrupts. However, the receiver shift register can continue to assemble
characters. Thus, if RXENA is set during the reception of a character, the complete character will be
transferred into the receiver buffer registers, SCIRXEMU and SCIRXBUF.
0
Prevent received characters from transfer into the SCIRXEMU and SCIRXBUF receiver buffers
1
Send received characters to SCIRXEMU and SCIRXBUF