MPC5553/MPC5554 Microcontroller Reference Manual, Rev. 5
Freescale Semiconductor 21-27
If start bit verification is not successful, the RT clock is reset and a new search for a start bit begins.
To determine the value of a data bit and to detect noise, eSCI recovery logic takes samples at RT8, RT9,
and RT10. Table 21-19 summarizes the results of the data bit samples.
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.
To verify a stop bit and to detect noise, recovery logic takes samples at RT8, RT9, and RT10. Table 21-20
summarizes the results of the stop bit samples.
101 No 0
110 No 0
111 No 0
Table 21-19. Data Bit Recovery
RT8, RT9, and RT10 Samples Data Bit Determination Noise Flag
000 0 0
001 0 1
010 0 1
011 1 1
100 0 1
101 1 1
110 1 1
111 1 0
Table 21-20. Stop Bit Recovery
RT8, RT9, and RT10 Samples Framing Error Flag Noise Flag
000 1 0
001 1 1
010 1 1
011 0 1
100 1 1
101 0 1
110 0 1
111 0 0
Table 21-18. Start Bit Verification (Continued)
RT3, RT5, and RT7 Samples Start Bit Verification Noise Flag
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