K60P100M100SF2RM Datasheet, PDF (1536/1809 Pages) Freescale Semiconductor, Inc – K60 Sub-Family Reference Manual

Functional description
Rx pin input
START BIT
LSB
NO START BIT FOUND
SAMPLES 1 1 1 1 1 1 1 1 1 0
0
1
100000000
RT CLOCK
RT CLOCK COUNT
RESET RT CLOCK
Figure 51-195. Start bit search example 5 (C7816[ISO_7816E] = 0)
In the following figure, a noise burst makes the majority of data samples RT8, RT9, and
RT10 high. In this example C7816[ISO_7816E] = 0. This sets the noise flag but does not
reset the RT clock. In start bits only, the RT8, RT9, and RT10 data samples are ignored.
In this example, if C7816[ISO_7816E] = 1 then a start bit would not have been detected
at all since at least two of the three samples (RT8, RT9, RT10) were high.
START BIT
LSB
Rx pin input
SAMPLES 1 1 1 1 1 1 1 1 1 0
0
0
01 0 1
RT CLOCK
RT CLOCK COUNT
RESET RT CLOCK
Figure 51-196. Start bit search example 6
51.4.2.5 Framing errors
If the data recovery logic does not detect a logic 1 where the stop bit should be in an
incoming frame, it sets the framing error flag, S1[FE] if S2[LBKDE] is disabled. A break
character when S2[LBKDE] is disabled also sets the S1[FE] because a break character
has no stop bit. The S1[FE] is set at the same time that received data is placed in the
receive data buffer. Framing errors are not supported when C7816[ISO7816E] is set/
enabled. However, if the S1[FE] is set data will not be received when C7816[ISO7816E]
is set.
1536
K60 Sub-Family Reference Manual, Rev. 6, Nov 2011
Freescale Semiconductor, Inc.