![](http://datasheet.mmic.net.cn/90000/MC68HC705X32FU_datasheet_3506466/MC68HC705X32FU_113.png)
MC68HC05X16
7-11
SERIAL COMMUNICATIONS INTERFACE
7
R8 — Receive data bit 8
This read-only bit is the ninth serial data bit received when the SCI system is congured for nine
data bit operation (M = 1). The most signicant bit (bit 8) of the received character is transferred
into this bit at the same time as the remaining eight bits (bits 0–7) are transferred from the serial
receive shift register to the SCI receive data register.
T8 — Transmit data bit 8
This read/write bit is the ninth data bit to be transmitted when the SCI system is congured for nine
data bit operation (M = 1). When the eight low order bits (bits 0–7) of a transmit character are
transferred from the SCI data register to the serial transmit shift register, this bit (bit 8) is transferred
to the ninth bit position of the shift register.
M — Mode (select character format)
The read/write M-bit controls the character length for both the transmitter and receiver at the same
time. The 9th data bit is most commonly used as an extra stop bit or it can also be used as a parity
1 (set)
–
Start bit, 9 data bits, 1 stop bit.
0 (clear) –
Start bit, 8 data bits, 1 stop bit.
WAKE — Wake-up mode select
This bit allows the user to select the method for receiver wake-up. The WAKE bit can be read or
1 (set)
–
Wake-up on address mark; if RWU is set, SCI will wake-up if the 8th
(if M=0) or the 9th (if M=1) bit received on the Rx line is set.
0 (clear) –
Wake-up on idle line; if RWU is set, SCI will wake-up after 11 (if M=0)
or 12 (if M=1) consecutive ‘1’s on the Rx line.
Table 7-1 Method of receiver wake-up
WAKE
M
Method of receiver wake-up
0x
Detection of an idle line allows the next data type received to cause the receive
data register to ll and produce an RDRF ag.
10
Detection of a received one in the eighth data bit allows an RDRF ag and
associated error ags.
11
Detection of a received one in the ninth data bit allows an RDRF ag and
associated error ags.
x = Don’t care
111
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com