SCI Registers
1040
SPRUHE8E – October 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
C28 Serial Communications Interface (SCI)
Table 13-15. SCI FIFO Transmit (SCIFFTX) Register Field Descriptions (continued)
Bit
Field
Value
Description
13
TXFIFO Reset
Transmit FIFO reset
0
Reset the FIFO pointer to zero and hold in reset
1
Re-enable transmit FIFO operation
12-8
TXFFST4-0
00000
Transmit FIFO is empty.
00001
Transmit FIFO has 1 words
00010
Transmit FIFO has 2 words
00011
Transmit FIFO has 3 words
0xxxx
Transmit FIFO has x words
10000
Transmit FIFO has 16 words
7
TXFFINT Flag
Transmit FIFO interrupt
0
TXFIFO interrupt has not occurred, read-only bit
1
TXFIFO interrupt has occurred, read-only bit
6
TXFFINT CLR
Transmit FIFO clear
0
Write 0 has no effect on TXFIFINT flag bit, Bit reads back a zero
1
Write 1 to clear TXFFINT flag in bit 7
5
TXFFIENA
Transmit FIFO interrupt enable
0
TX FIFO interrupt based on TXFFIL match (less than or equal to) is disabled
1
TX FIFO interrupt based on TXFFIL match (less than or equal to) is enabled.
4-0
TXFFIL4-0
TXFFIL4
−
0 Transmit FIFO interrupt level bits.
The transmit FIFO generates an interrupt whenever the FIFO status bits (TXFFST4-0) are less than
or equal to the FIFO level bits (TXFFIL4-0). The maximum value that can be assigned to these bits
to generate an interrupt cannot be more than the depth of the TX FIFO. The default value of these
bits after reset is 00000b. Users should set TXFFIL to best fit their application needs by weighing
between the CPU overhead to service the ISR and the best possible usage of SCI bus bandwidth.
Figure 13-23. SCI FIFO Receive (SCIFFRX) Register — Address 705Bh
15
14
13
12
11
10
9
8
RXFFOVF
RXFFOVR CLR
RXFIFO Reset
RXFIFST4
RXFFST3
RXFFST2
RXFFST1
RXFFST0
R-0
W
−
0
R/W
−
1
R-0
R-0
R-0
R-0
R-0
7
6
5
4
3
2
1
0
RXFFINT Flag
RXFFINT CLR
RXFFIENA
RXFFIL4
RXFFIL3
RXFFIL2
RXFFIL1
RXFFIL0
R-0
W
−
0
R/W
−
0
R/W
−
1
R/W
−
1
R/W
−
1
R/W
−
1
R/W
−
1
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
Table 13-16. SCI FIFO Receive (SCIFFRX) Register Field Descriptions
Bit
Field
Value
Description
15
RXFFOVF
Receive FIFO overflow. This will function as flag, but cannot generate interrupt by itself. This
condition will occur while receive interrupt is active. Receive interrupts should service this flag
condition.
0
Receive FIFO has not overflowed, read-only bit
1
Receive FIFO has overflowed, read-only bit. More than 16 words have been received in to the
FIFO, and the first received word is lost
14
RXFFOVR CLR
RXFFOVF clear
0
Write 0 has no effect on RXFFOVF flag bit. Bit reads back a zero
1
Write 1 to clear RXFFOVF flag in bit 15
13
RXFIFO Reset
Receive FIFO reset
0
Write 0 to reset the FIFO pointer to zero, and hold in reset.
1
Re-enable receive FIFO operation