Datasheet

Serial Communications Interface (SCI)
Functional Description
MC9S12DP256 — Revision 1.1
Serial Communications Interface (SCI)
Figure 70 Start Bit Search Example 2
In Figure 71, 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
bit time, the data samples RT8, RT9, and RT10 are within the bit time
and data recovery is successful.
Figure 71 Start Bit Search Example 3
RESET RT CLOCK
RT1 RT1 RT1 RT1 RT1 RT1 RT2 RT3 RT4 RT5 RT6 RT7 RT8
RT11 RT10
RT9
RT14 RT13 RT12
RT2 RT1
RT16 RT15
RT3 RT4 RT5 RT6 RT7
SAMPLES
RT CLOCK
RT CLOCK COUNT
ACTUAL START BIT
sci_rx_ind
1111110000
LSB
00
PERCEIVED START BIT
RESET RT CLOCK
RT1 RT1 RT1 RT1 RT2 RT3 RT4 RT5 RT6 RT7 RT8 RT9
RT10 RT13 RT12 RT11 RT16 RT15 RT14
RT4 RT3 RT2 RT1 RT5 RT6 RT7 RT8 RT9
SAMPLES
RT CLOCK
RT CLOCK COUNT
ACTUAL START BIT
sci_rx_ind
101110000
LSB
0
PERCEIVED START BIT
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Freescale Semiconductor, Inc.
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