Enhanced Serial Communication Interface (eSCI)
MPC5510 Microcontroller Family Reference Manual, Rev. 1
Freescale Semiconductor
24-17
Preliminary
Figure 24-11. eSCI Operation Block Diagram
24.4.1
Data Format
The eSCI uses the standard NRZ mark/space data format. Each data character is contained in a frame that
includes a start bit, eight or nine data bits, and a stop bit. Clearing the M bit in eSCI control register 1
configures the eSCI for 8-bit data characters. A frame with eight data bits has a total of 10 bits. Setting the
M bit configures the eSCI for 9-bit data characters. A frame with nine data bits has a total of 11 bits.
When the eSCI is configured for 9-bit data characters, the ninth data bit is the T8 bit in the eSCI data
register (ESCI
x
_DR). It remains unchanged after transmission and can be used repeatedly without
rewriting it. A frame with nine data bits has a total of 11 bits.
The two different data formats are illustrated in
show the
number of each type of bit in 8-bit data format and 9-bit data format, respectively.
Figure 24-12. eSCI Data Formats
eSCI data
RE
register
Receive and
wakeup control
RWU
LOOPS
RSRC
M
WAKE
ILT
PE
PT
TE
LOOPS
SBK
RSRC
Data format
control
Transmit
control
Transmit
shift register
NF
FE
PF
RAF
R8
IDLE
RDRF
OR
ILIE
RIE
BAUD rate
generator
Bus
clock
IRQ to
CPU
TDRE
TC
TIE
TCIE
TXD
÷16
T8
SBR0–SBR12
RXD
SCI data
register
Receive
shift register
IDLE
IRQ
TC
IRQ
TDRE
IRQ
RDRF/
OR IRQ
Parity or
STOP
bit
Bit 0
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
Bit 7
Next
START
bit
START
bit
data bit
8-bit data format
Bit M in ESCI
x
_CR1 clear
STOP
bit
Bit 0
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
Bit 7
Next
START
bit
START
bit
9-bit data format
Bit M in ESCI
x
_CR1 set
Parity or
Bit 8
data bit