MC9S12T64 Datasheet, PDF (445/608 Pages) Motorola, Inc – Specification

Freescale Semiconductor, Inc.
Serial Communications Interface (SCI)
Functional Description
Table 78 Data Bit Recovery
RT8, RT9, and RT10 Samples
000
001
010
011
100
101
110
111
Data Bit Determination
0
0
0
1
0
1
1
1
Noise Flag
0
1
1
1
1
1
1
0
NOTE:
The RT8, RT9, and RT10 samples do not affect start bit verification. If
any or all of the RT8, RT9, and RT10 start bit samples are logic 1s
following a successful start bit verification, the noise flag (NF) is set and
the receiver assumes that the bit is a start bit (logic 0).
To verify a stop bit and to detect noise, recovery logic takes samples at
RT8, RT9, and RT10. Table 79 summarizes the results of the stop bit
samples.
Table 79 Stop Bit Recovery
RT8, RT9, and RT10 Samples
000
001
010
011
100
101
110
111
Framing Error Flag
1
1
1
0
1
0
0
0
Noise Flag
0
1
1
1
1
1
1
0
In Figure 81, the verification samples RT3 and RT5 determine that the
first low detected was noise and not the beginning of a start bit. The RT
clock is reset and the start bit search begins again. The noise flag is not
set because the noise occurred before the start bit was found.
Serial Communications Interface (SCI)
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MC9S12T64Revision 1.1.1