MC9S12T64 Datasheet, PDF (446/608 Pages) Motorola, Inc – Specification

Freescale Semiconductor, Inc.
Serial Communications Interface (SCI)
RX Input Signal
START BIT
LSB
SAMPLES 1 1 1 0
1
110
0
0
0000
RT CLOCK
RT CLOCK COUNT
RESET RT CLOCK
Figure 81 Start Bit Search Example 1
In Figure 82, verification sample at RT3 is high. The RT3 sample sets
the noise flag. Although the perceived bit time is misaligned, the data
samples RT8, RT9, and RT10 are within the bit time and data recovery
is successful.
RX Input Signal
PERCEIVED START BIT
ACTUAL START BIT
LSB
SAMPLES 1 1 1 1 1 0
1
0
0000
RT CLOCK
RT CLOCK COUNT
RESET RT CLOCK
Figure 82 Start Bit Search Example 2
In Figure 83, a large burst of noise is perceived as the beginning of a
start bit, although the test sample at RT5 is high. The RT5 sample sets
the noise flag. Although this is a worst-case misalignment of perceived
MC9S12T64Revision 1.1.1
Serial Communications Interface (SCI)
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