SERIAL COMMUNICATION INTERFACE (SCI)
MOTOROLA
PORT C
6 - 15
The multidrop asynchronous modes are compatible with the MC68681 DUART, the
M68HC11 SCI interface, and the Intel 8051 serial interface.
The synchronous data mode is essentially a high-speed shift register used for I/O expan-
sion and stream-mode channel interfaces. A gated transmit and receive clock that is com-
patible with the Intel 8051 serial interface mode 0 accomplishes data synchronization. The
word formats are shown in Table 6-1 (also see Figure 6-10 (a) and (b)).
Table 6-1 Word Formats
When odd parity is selected, the transmitter will count the number of bits in the data word.
If the total is not an odd number, the parity bit is made equal to one and thus produces an
odd number. If the receiver counts an even number of ones, an error in transmission has
occurred. When even parity is selected, an even number must result from the calculation
performed at both ends of the line or an error in transmission has occurred.
The word-select bits are cleared by hardware and software reset.
WDS2
WDS1
WDS0
Word Formats
0
0
0
8-Bit Synchronous Data (shift register mode)
0
0
1
Reserved
0
1
0
10-Bit Asynchronous (1 start, 8 data, 1 stop)
0
1
1
Reserved
1
0
0
11-Bit Asynchronous (1 start, 8 data, 1 even parity, 1 stop)
1
0
1
11-Bit Asynchronous (1 start, 8 data, 1 odd parity, 1 stop)
1
1
0
11-Bit Multidrop (1 start, 8 data, 1 data type, 1 stop)
1
1
1
Reserved
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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