MC68HC08AS32 Datasheet, PDF (165/280 Pages) Motorola, Inc – M68HC08 Family of 8-bit microcontroller units (MCUs)

PTE1/RxD
START BIT
LSB
SAMPLES
RT
CLOCK
RT CLOCK
STATE
RT CLOCK
RESET
START BIT
QUALIFICATION
START BIT
VERIFICATION
DATA
SAMPLING
Figure 12-7. Receiver Data Sampling
To verify the start bit and to detect noise, data recovery logic takes samples at RT3,
RT5, and RT7. Table 12-2 summarizes the results of the start bit verification
samples.
Table 12-2. Start Bit Verification
RT3, RT5, and RT7
Samples
000
001
010
011
100
101
110
111
Start Bit
Verification
Yes
Yes
Yes
No
Yes
No
No
No
Noise Flag
0
1
1
0
1
0
0
0
If start bit verification is not successful, the RT clock is reset and a new search for
a start bit begins.
MC68HC08AS32 — Rev. 4.1
Freescale Semiconductor
Data Sheet
165