MSC8113 Reference Manual, Rev. 0
21-12
Freescale Semiconductor
UART
21.2.2 Data Sampling
The receiver samples
URXD
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 between the baud rate
generated by RT clock and the target baud rate, the RT clock (see Figure 21-9) is
re-synchronized:
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).
To locate the start bit, data sampling logic searches for a logic 0 preceded by three logic 1s. When
the falling edge of a possible start bit occurs, the RT clock logic begins to count to 16.
Figure 21-8. UART Receiver Block Diagram
Al
l O
n
es
M
WAKE
ILT
PE
PT
RE
H 8 7 6 5 4 3 2 1 0 L
11-Bit Receive Shift Register
St
op b
it
St
a
rt
bi
t
Data
Wake-up
Parity
Checking
MS
B
SCI Data Register R[7–0]
R8
RIE
ILIE
RWU
RDRF
OR
NF
FE
PF
URXD
System
Idle Interrupt Source
RDRF Interrupt Source
SBR[12–0]
Baud-Rate
From UTXD
OR Transmitter
Clock
IDLE
RAF
Sampling
Logic
OR Interrupt Source
Generator
sa
mpl
e
sa
mpl
e
Loop
LOOPS
RSRC
Control
IPBus
Summary of Contents for MSC8113
Page 1: ...MSC8113 Reference Manual Tri Core 16 Bit Digital Signal Processor MSC8113RM Rev 0 May 2008 ...
Page 20: ...MSC8113 Reference Manual Rev 0 xx Freescale Semiconductor Contents ...
Page 28: ...MSC8113 Reference Manual Rev 0 xxviii Freescale Semiconductor ...
Page 56: ...MSC8113 Reference Manual Rev 0 1 28 Freescale Semiconductor MSC8113 Overview ...
Page 76: ...MSC8113 Reference Manual Rev 0 2 20 Freescale Semiconductor SC140 Core Overview ...
Page 134: ...MSC8113 Reference Manual Rev 0 4 30 Freescale Semiconductor System Interface Unit SIU ...
Page 168: ...MSC8113 Reference Manual Rev 0 6 18 Freescale Semiconductor Boot Program ...
Page 180: ...MSC8113 Reference Manual Rev 0 7 12 Freescale Semiconductor Clocks ...
Page 260: ...MSC8113 Reference Manual Rev 0 8 80 Freescale Semiconductor Memory Map ...
Page 300: ...MSC8113 Reference Manual Rev 0 9 40 Freescale Semiconductor Extended Core ...
Page 304: ...MSC8113 Reference Manual Rev 0 10 4 Freescale Semiconductor MQBus and M2 Memory ...
Page 308: ...MSC8113 Reference Manual Rev 0 11 4 Freescale Semiconductor SQBus ...
Page 590: ...MSC8113 Reference Manual Rev 0 17 46 Freescale Semiconductor Interrupt Processing ...
Page 614: ...MSC8113 Reference Manual Rev 0 18 24 Freescale Semiconductor Debugging ...
Page 622: ...MSC8113 Reference Manual Rev 0 19 8 Freescale Semiconductor Internal Peripheral Bus IPBus ...
Page 724: ...MSC8113 Reference Manual Rev 0 21 32 Freescale Semiconductor UART ...
Page 920: ...MSC8113 Reference Manual Rev 0 25 150 Freescale Semiconductor Ethernet Controller ...
Page 1171: ...MSC8113 Reference Manual Rev 0 Freescale Semiconductor C 61 EF wait_rts P 01077FFC 9F rts 71 ...
Page 1172: ...MSC8113 Reference Manual Rev 0 C 62 Freescale Semiconductor MSC8113 Boot Code ...
Page 1202: ...MSC8113 Reference Manual Rev 0 Index 30 Freescale Semiconductor Index ...