mc9s12xd256 Freescale Semiconductor, Inc, mc9s12xd256 Datasheet - Page 506

• Manufacturer Part Number: mc9s12xd256
• Description: Hcs12x Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Chapter 11 Serial Communication Interface (S12SCIV5)
In
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 11-25
synchronization with the start bit time, it does set the noise flag.
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Figure
RT Clock Count
Reset RT Clock
RT Clock Count
Reset RT Clock
RT Clock
RT Clock
Samples
Samples
11-24, a large burst of noise is perceived as the beginning of a start bit, although the test sample
RXD
RXD
shows the effect of noise early in the start bit time. Although this noise does not affect proper
1
1
1
1
1
1
1
0
1
Figure 11-24. Start Bit Search Example 3
Figure 11-25. Start Bit Search Example 4
1
0
MC9S12XDP512 Data Sheet, Rev. 2.17
1
1
1
1
Perceived Start Bit
0
0
0
1
0
0
Perceived and Actual Start Bit
0
Actual Start Bit
Freescale Semiconductor
LSB
LSB