RX ERROR = 1 when any of bits 5 through 2 is a 1 value
RXRDY or BRKDT causes an interrupt
if RX/BK INT ENA (SCICTL2.1) = 1
RX ERROR
RXRDY
BRKDT
FE
OE
PE
RXWAKE
Reserved
7
6
5
4
3
2
1
0
SCI Registers
1038
SPRUHE8E – October 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
C28 Serial Communications Interface (SCI)
Figure 13-18. Register SCIRXST Bit Associations — Address 7055h
13.3.7 Receiver Data Buffer Registers (SCIRXEMU, SCIRXBUF)
Received data is transferred from RXSHF to SCIRXEMU and SCIRXBUF. When the transfer is complete,
the RXRDY flag (bit SCIRXST.6) is set, indicating that the received data is ready to be read. Both
registers contain the same data; they have separate addresses but are not physically separate buffers.
The only difference is that reading SCIRXEMU does not clear the RXRDY flag; however, reading
SCIRXBUF clears the flag.
13.3.7.1 Emulation Data Buffer (SCIRXEMU)
Normal SCI data-receive operations read the data received from the SCIRXBUF register. The SCIRXEMU
register is used principally by the emulator (EMU) because it can continuously read the data received for
screen updates without clearing the RXRDY flag. SCIRXEMU is cleared by a system reset.
This is the register that should be used in an emulator watch window to view the contents of the
SCIRXBUF register.
SCIRXEMU is not physically implemented; it is just a different address location to access the SCIRXBUF
register without clearing the RXRDY flag.
Figure 13-19. Emulation Data Buffer Register (SCIRXEMU) — Address 7056h
7
6
5
4
3
2
1
0
ERXDT7
ERXDT6
ERXDT5
ERXDT4
ERXDT3
ERXDT2
ERXDT1
ERXDT0
R-0
R-0
R-0
R-0
R-0
R-0
R-0
R-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
13.3.7.2 Receiver Data Buffer (SCIRXBUF)
When the current data received is shifted from RXSHF to the receiver buffer, flag bit RXRDY is set and
the data is ready to be read. If the RX/BK INT ENA bit (SCICTL2.1) is set, this shift also causes an
interrupt. When SCIRXBUF is read, the RXRDY flag is reset. SCIRXBUF is cleared by a system reset.
(1)
Applicable only if the FIFO is enabled.
Figure 13-20. SCI Receive Data Buffer Register (SCIRXBUF) — Address 7057h
15
14
13
8
SCIFFFE
(1)
SCIFFPE
(1)
Reserved
R
−
0
R
−
0
R
−
0
7
6
5
4
3
2
1
0
RXDT7
RXDT6
RXDT5
RXDT4
RXDT3
RXDT2
RXDT1
RXDT0
R
−
0
R
−
0
R
−
0
R
−
0
R
−
0
R
−
0
R
−
0
R
−
0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset