Transmitter
MSC8113 Reference Manual, Rev. 0
Freescale Semiconductor
21-7
21.1.1 Character Transmission
To transmit data, one of the SC140 cores or an external host writes the data character to the SCI
Data Register (SCIDR), which is then transferred to the transmitter shift register. The transmitter
shift register then shifts out the data bits on the
UTXD
signal, after it prefaces them with a start bit
and appends them with a stop bit. The SCI data register is the write-only buffer between the
IPBus and the transmit shift register.
The UART also sets a flag, the transmit data register empty flag (TDRE), every time it transfers
data from the buffer (SCIDR) to the transmitter shift register. If the Transmit Interrupt Enable
(TIE) bit in the SCICR is set, the TDRE flag asserts a UART interrupt request. The transmit
interrupt service routine responds to this flag by writing another character to the transmitter
buffer (SCIDR), while the shift register is still shifting out the first character. If the TDRE flag is
set and no new data or break character transferred to the shift register, the UART sets a flag,
transmit complete (TC) and
UTXD
becomes idle.
Figure 21-6. Transmitter Block Diagram
PE
PT
H 8
7
6
5
4
3
2
1
0
L
11-Bit Transmit Shift Register
Sto
p
Sta
rt
T8
TDRE
TIE
TCIE
SBK
TC
Parity
Generation
MS
B
SCI Data Register T[7–0]
Lo
ad F
rom
S
C
IDR
S
h
ift E
nabl
e
Pr
e
a
mb
le (
A
ll O
nes
)
Br
e
a
k (A
ll
0s
)
M
SBR[12–0]
Baud-Rate
³ 16
UTXD
TDRE Interrupt Source
TC Interrupt Source
System Clock
Loop
LOOPS
RSRC
TE
To
Control
Receiver
Generator
Transmitter 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 ...