UART Registers
19.5.1.27 Supplementary Control Register (SCR)
The supplementary control register (SCR) is shown in
and described in
NOTE:
Bit 4 enables the wake-up interrupt, but this interrupt is not mapped into the IIR register.
Therefore, when an interrupt occurs and there is no interrupt pending in the IIR register, the
SSR[1] bit must be checked. To clear the wake-up interrupt, bit SCR[4] must be reset to 0.
Figure 19-60. Supplementary Control Register (SCR)
15
8
Reserved
R-0
7
6
5
4
3
2
1
0
RXTRIGGRANU1
TXTRIGGRANU1
DSRIT
RXCTSDSRWAKEUPENABLE
TXEMPTYCTLIT
DMAMODE2
DMAMODECTL
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 19-58. Supplementary Control Register (SCR) Field Descriptions
Bit
Field
Value
Description
15-8
Reserved
0
Reserved.
7
RXTRIGGRANU1
0
Disables the granularity of 1 for trigger RX level.
1
Enables the granularity of 1 for trigger RX level.
6
TXTRIGGRANU1
0
Disables the granularity of 1 for trigger TX level.
1
Enables the granularity of 1 for trigger TX level.
5
DSRIT
0
Disables DSR interrupt.
1
Enables DSR interrupt.
4
RXCTSDSRWAKEUPENABLE
RX CTS wake-up enable.
0
Disables the WAKE UP interrupt and clears SSR[1].
1
Waits for a falling edge of RX, CTS, or DSR pins to generate an interrupt.
3
TXEMPTYCTLIT
0
Normal mode for THR interrupt.
1
THR interrupt is generated when TX FIFO and TX shift register are empty.
2-1
DMAMODE2
0-3h
Specifies the DMA mode valid if SCR[0] = 1:
0
DMA mode 0 (no DMA).
1h
DMA mode 1 (UARTnDMAREQ[0] in TX, UARTnDMAREQ[1] in RX)
2h
DMA mode 2 (UARTnDMAREQ[0] in RX)
3h
DMA mode 3 (UARTnDMAREQ[0] in TX)
0
DMAMODECTL
0
The DMAMODE is set with FCR[3].
1
The DMAMODE is set with SCR[2:1].
3529
SPRUH73H – October 2011 – Revised April 2013
Universal Asynchronous Receiver/Transmitter (UART)
Copyright © 2011–2013, Texas Instruments Incorporated