Chapter 12 Serial Communication Interface (S12SCIV6)
S12ZVHY/S12ZVHL Family Reference Manual Rev. 1.05
506
Freescale Semiconductor
shows a burst of noise near the beginning of the start bit that resets the RT clock. The sample
after the reset is low but is not preceded by three high samples that would qualify as a falling edge.
Depending on the timing of the start bit search and on the data, the frame may be missed entirely or it may
set the framing error flag.
Figure 12-26. Start Bit Search Example 5
, a noise burst makes the majority of data samples RT8, RT9, and RT10 high. 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.
Figure 12-27. Start Bit Search Example 6
12.4.6.4
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, FE, in SCI status register 1 (SCISR1). A break character also sets the FE flag
because a break character has no stop bit. The FE flag is set at the same time that the RDRF flag is set.
Reset RT Clock
RT
1
RT
1
RT
1
RT
1
RT
1
RT
1
RT
1
RT
1
RT
1
RT
1
RT
2
RT
3
RT
4
RT
7
RT
6
RT
5
RT
1
RT
1
RT
1
RT
1
RT
1
RT
1
RT
1
RT
1
RT
1
RT
1
RT
1
RT
1
Samples
RT Clock
RT Clock Count
Start Bit
RXD
1
1
1
1
1
0
1
0
LSB
1
1
1
1
1
0
0
0
0
0
0
0
0
No Start Bit Found
Reset RT Clock
RT
1
RT
1
RT
1
RT
1
RT
1
RT
1
RT
1
RT
1
RT
1
RT
1
RT
2
RT
3
RT
4
RT
7
RT
6
RT
5
RT
10
RT
9
RT
8
RT
14
RT
13
RT
12
RT
11
RT
15
RT
16
RT
1
RT
2
RT
3
Samples
RT Clock
RT Clock Count
Start Bit
RXD
1
1
1
1
1
0
0
0
LSB
1
1
1
1
0
1
1
0
Содержание MC9S12ZVHL32
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Страница 686: ...Chapter 20 ECC Generation module SRAM_ECCV1 S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 686 Freescale Semiconductor...
Страница 752: ...Chapter 22 Supply Voltage Sensor BATSV2 S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 752 Freescale Semiconductor...
Страница 774: ...Chapter 23 LIN Physical Layer S12LINPHYV2 S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 774 Freescale Semiconductor...
Страница 788: ...Appendix A MCU Electrical Specifications S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 788 Freescale Semiconductor...
Страница 794: ...Appendix B ADC Electricals S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 794 Freescale Semiconductor...
Страница 798: ...Appendix D IRC Electrical Specifications S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 798 Freescale Semiconductor...
Страница 802: ...Appendix F MSCAN Electrical Specifications S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 802 Freescale Semiconductor...
Страница 806: ...Appendix G NVM Electrical Parameters S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 806 Freescale Semiconductor...
Страница 810: ...Appendix H BATS Electrical Specifications S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 810 Freescale Semiconductor...
Страница 816: ...Appendix K OSC32K Electrical Specifications S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 816 Freescale Semiconductor...
Страница 822: ...Appendix L SPI Electrical Specifications S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 822 Freescale Semiconductor...
Страница 826: ...Appendix M LINPHY Electrical Specifications S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 826 Freescale Semiconductor...
Страница 829: ...Appendix O Package Information S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 830 Freescale Semiconductor O 1 144 LQFP...
Страница 830: ...Appendix O Package Information S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 Freescale Semiconductor 831...
Страница 831: ...Appendix O Package Information S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 832 Freescale Semiconductor...
Страница 832: ...Appendix O Package Information S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 Freescale Semiconductor 833 O 2 100 LQFP...
Страница 833: ...Appendix O Package Information S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 834 Freescale Semiconductor...
Страница 834: ...Appendix O Package Information S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 Freescale Semiconductor 835...
Страница 835: ...Appendix O Package Information S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 836 Freescale Semiconductor...