MMC2107 Datasheet, PDF (360/618 Pages) –

Freescale Semiconductor, Inc.
Serial Communications Interface Modules (SCI1 and SCI2)
In Figure 16-18, noise is perceived as the beginning of a start bit
although the RT3 sample is high. The RT3 sample sets the noise flag.
Although the perceived bit time is misaligned, the RT8, RT9, and RT10
data samples are within the bit time, and data recovery is successful.
PERCEIVED START BIT
ACTUAL START BIT
LSB
RXD
SAMPLES 1 1 1 1 1 0
1
0
0000
RT CLOCK
RT CLOCK COUNT
RESET RT CLOCK
Figure 16-18. Start Bit Search Example 2
In Figure 16-19 a large burst of noise is perceived as the beginning of a
start bit, although the RT5 sample is high. The RT5 sample sets the
noise flag. Although this is a worst-case misalignment of perceived bit
time, the data samples RT8, RT9, and RT10 are within the bit time and
data recovery is successful.
PERCEIVED START BIT
ACTUAL START BIT
LSB
RXD
SAMPLES 1 1 1 0
0
1
0000
RT CLOCK
RT CLOCK COUNT
RESET RT CLOCK
Technical Data
360
Figure 16-19. Start Bit Search Example 3
Serial Communications Interface Modules (SCI1 and SCI2)
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MMC2107 – Rev. 2.0
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