
ST72321xx-Auto Serial communications interface (SCI)
Doc ID 13829 Rev 1 151/243
15.7.4 Data register (SCIDR)
This register contains the Received or Transmitted data character, depending on whether it
is read from or written to.
The Data register performs a double function (read and write) since it is composed of two
registers, one for transmission (TDR) and one for reception (RDR).
The TDR register provides the parallel interface between the internal bus and the output
shift register (see Figure 62).
The RDR register provides the parallel interface between the input shift register and the
internal bus (see Figure 62).
15.7.5 Baud rate register (SCIBRR)
2RE
Receiver enable
This bit enables the receiver. It is set and cleared by software.
0: Receiver is disabled
1: Receiver is enabled and begins searching for a start bit
1RWU
Receiver wake-up
This bit determines if the SCI is in mute mode or not. It is set and cleared by software
and can be cleared by hardware when a wake-up sequence is recognized.
0: Receiver in Active mode
1: Receiver in Mute mode
Note: Before selecting Mute mode (setting the RWU bit), the SCI must receive some
data first, otherwise it cannot function in Mute mode with wake-up by idle line
detection.
0 SBK
Send break
This bit set is used to send break characters. It is set and cleared by software.
0: No break character is transmitted
1: Break characters are transmitted
Note: If the SBK bit is set to ‘1’ and then to ‘0’, the transmitter sends a BREAK word
at the end of the current word.
Table 75. SCICR2 register description (continued)
Bit Name Function
SCIDR Reset value: Undefined
76543210
DR[7:0]
RW
SCIBRR Reset value: 0000 0000 (00h)
76543210
SCP[1:0] SCT[2:0] SCR[2:0]
RW RW RW
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