Enhanced Serial Communication Interface (eSCI)
26-38
Freescale Semiconductor
PXR40 Microcontroller Reference Manual, Rev. 1
26.4.5.3.15
Start Bit Sampling
Figure 26-32. Start Bit Sampling and Strobing
Start Bit Qualification
To adjust for baud rate mismatch, the cyclic sample counter RSC is re-synchronized by reset after
successful start bit qualification. A start bit is successfully qualified, if no reception is ongoing and three
consecutive high samples are followed immediately by a low sample.
Start Bit Verification
After the successful start bit qualification the receiver starts to verify the start bit by a two out of three
samples majority voting.
A start bit is verified if at least two out of the three sample RSC3, RSC5, and RSC5 are sampled low. Noise
is detected when exactly one out of the three samples is high. The results of the start bit verification is
summarized in
.
If the start bit verification was
not
successful
, the receiver resumes the start bit qualification. If the start bit
verification was
successful
, the receiver continues sampling to perform noise detection on the samples at
RS8, RS9, and RS10. The results of the start bit noise detection is summarized in
Table 26-32. Start Bit Verification Result
[RS3, RS5, RS7]
Start Bit Verified
Noise Detected
000
Yes
No
001
Yes
Yes
010
Yes
Yes
100
Yes
Yes
011
No
No
101
No
No
110
No
No
111
No
No
Sampled Value
RCLK
START BIT
Receiver Input
START BIT
QUALIFICATION
1
1
1
1
1
0
0
0
0
0
0
0
4
5
6
7
8
1
2
sample counter reset
3
RSC
4
5
6
7
0
8
9
10
11
12
13
14
15
16
1
0
0
START BIT
VERIFICATION
NOISE
DETECTION
data strobing
0
1
0
0
1
0
0
0
2
sample counter wrap
Summary of Contents for PXR4030
Page 1: ...PXR40 Microcontroller Reference Manual Devices Supported PXR4030 PXR4040 PXR40RM Rev 1 06 2011...
Page 30: ...PXR40 Microcontroller Reference Manual Rev 1 Freescale Semiconductor xxx...
Page 40: ...PXR40 Microcontroller Reference Manual Rev 1 xl Freescale Semiconductor...
Page 66: ...Memory Map PXR40 Microcontroller Reference Manual Rev 1 2 4 Freescale Semiconductor...
Page 120: ...Signal Descriptions 3 54 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Page 860: ...FlexCAN Module 24 50 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Page 1167: ...Decimation Filter Freescale Semiconductor 28 53 PXR40 Microcontroller Reference Manual Rev 1...
Page 1168: ...Decimation Filter 28 54 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...