SCI Control Registers
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SPNU563A–March 2018
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Serial Communication Interface (SCI) Module
30.7.12 SCI Data Buffers (SCIED, SCIRD, SCITD)
The SCI has three addressable registers in which transmit and receive data is stored.
30.7.12.1 Receiver Emulation Data Buffer (SCIED)
The SCIED register is addressed at a location different from SCIRD, but is physically the same register.
Figure 30-19 and Table 30-18 illustrate this register.
Figure 30-19. Receiver Emulation Data Buffer (SCIED) [offset = 30h]
31 16
Reserved
R-0
15 8 7 0
Reserved ED
R-0 R-0
LEGEND: R = Read only; -n = value after reset
Table 30-18. Receiver Emulation Data Buffer (SCIED) Field Descriptions
Bit Field Value Description
31-8 Reserved 0 Reads return 0. Writes have no effect.
7-0 ED 0-FFh Emulator data. Reading SCIED[7:0] does not clear the RXRDY flag (SCIFLR[9]), unlike reading
SCIRD. This register should be used only by an emulator that must continually read the data
buffer without affecting the RXRDY flag.
30.7.12.2 Receiver Data Buffer (SCIRD)
This register provides a location for the receiver data. Figure 30-20 and Table 30-19 illustrate this register.
Figure 30-20. Receiver Data Buffer (SCIRD) [offset = 34h]
31 16
Reserved
R-0
15 8 7 0
Reserved RD
R-0 R-0
LEGEND: R = Read only; -n = value after reset
Table 30-19. Receiver Data Buffer (SCIRD) Field Descriptions
Bit Field Value Description
31-8 Reserved 0 Reads return 0. Writes have no effect.
7-0 RD 0-FFh Receiver data. When a frame has been completely received, the data in the frame is transferred
from the receiver shift register SCIRXSHF to this register. As this transfer occurs, the RXRDY flag
(SCIFLR[9]) is set and a receive interrupt is generated if SET RX INT bit (SCISETINT[9]) is set.
Note: When the data is read from SCIRD, the RXRDY flag (SCIFLR[9]) is automatically
cleared.
NOTE: When the SCI receives data that is fewer than eight bits in length, it loads the data into this
register in a left-justified format padded with trailing zeros. Therefore, the user software
should perform a logical shift on the data by the correct number of positions to make it right
justified.
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