mc68hc908sr12 Freescale Semiconductor, Inc, mc68hc908sr12 Datasheet - Page 264

• Manufacturer Part Number: mc68hc908sr12
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Serial Communications Interface (SCI)
16.5.3.3 Data Sampling
Data Sheet
264
RT CLOCK
RT CLOCK
SAMPLES
CLOCK
RESET
STATE
RxD
RT
The receiver samples the RxD pin at the RT clock rate. The RT clock is
an internal signal with a frequency 16 times the baud rate. To adjust for
baud rate mismatch, the RT clock is resynchronized at the following
times (see
To locate the start bit, data recovery logic does an asynchronous search
for a logic 0 preceded by three logic 1s. When the falling edge of a
possible start bit occurs, the RT clock begins to count to 16.
•
•
QUALIFICATION
Figure 16-6. Receiver Data Sampling
START BIT
After every start bit
After the receiver detects a data bit change from logic 1 to logic 0
(after the majority of data bit samples at RT8, RT9, and RT10
returns a valid logic 1 and the majority of the next RT8, RT9, and
RT10 samples returns a valid logic 0)
Serial Communications Interface (SCI)
Figure
16-6):
VERIFICATION
START BIT
START BIT
MC68HC908SR12•MC68HC08SR12 — Rev. 5.0
SAMPLING
DATA
Freescale Semiconductor
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