Datasheet

Functional Description
MC68HC908GR16 Data Sheet, Rev. 5.0
Freescale Semiconductor 149
14.4 Functional Description
Figure 14-2 shows the structure of the ESCI module. The ESCI allows full-duplex, asynchronous, NRZ
serial communication between the MCU and remote devices, including other MCUs. The transmitter and
receiver of the ESCI operate independently, although they use the same baud rate generator. During
normal operation, the CPU monitors the status of the ESCI, writes the data to be transmitted, and
processes received data.
Figure 14-2. ESCI Module Block Diagram
SCTE
TC
SCRF
IDLE
OR
NF
FE
PE
SCTIE
TCIE
SCRIE
ILIE
TE
RE
RWU
SBK
R8
T8
ORIE
FEIE
PEIE
BKF
RPF
ESCI DATA
RECEIVE
SHIFT REGISTER
ESCI DATA
REGISTER
TRANSMIT
SHIFT REGISTER
NEIE
M
WAKE
ILTY
FLAG
CONTROL
TRANSMIT
CONTROL
RECEIVE
CONTROL
DATA SELECTION
CONTROL
WAKEUP
PTY
PEN
REGISTER
TRANSMITTER
INTERRUPT
CONTROL
RECEIVER
INTERRUPT
CONTROL
ERROR
INTERRUPT
CONTROL
CONTROL
ENSCI
LOOPS
ENSCI
INTERNAL BUS
TXINV
LOOPS
÷ 4
÷ 16
PRE-
SCALER
BAUD RATE
GENERATOR
BUS CLOCK
RxD
TxD
ARBITER-
SCI_TxD
RxD
LINR
LINT
CGMXCLK
ESCIBDSRC FROM CONFIG2
SL
SL=1 -> SCI_CLK = BUSCLK
SL=0 -> SCI_CLK = CGMXCLK
SCI_CLK
BUS CLOCK
ACLK BIT IN SCIACTL
SL
ENHANCED
PRESCALER