MC68HC11F1CFN5 MOTOROLA [Motorola, Inc], MC68HC11F1CFN5 Datasheet - Page 42

• Manufacturer Part Number: MC68HC11F1CFN5
• Description: Technical Summary 8-Bit Microcontroller
• Manufacturer: MOTOROLA [Motorola, Inc]

9 Serial Communications Interface (SCI)
9.1 SCI Block Diagrams
42
TRANSMITTER
MOTOROLA
BAUD RATE
QUESTS
SCI Rx
CLOCK
The SCI, a universal asynchronous receiver transmitter (UART) serial communications interface, is one
of two independent serial I/O subsystems in the MC68HC11F1 and MC68HC11FC0. The SCI has a
standard non-return to zero (NRZ) format (one start bit, eight or nine data bits, and one stop bit) and
several selectable baud rates. The transmitter and receiver are independent but use the same data for-
mat and bit rate.
SCCR1
SCI INTERRUPT
REQUEST
SCI CONTROL 1
H
(8) 7
10 (11) - BIT Tx SHIFT REGISTER
SCDR Tx BUFFER
6
5
Figure 9 SCI Transmitter Block Diagram
4
TDRE
TIE
TC
TCIE
3
CONTROL LOGIC
TRANSMITTER
2
SCSR1
1
0
L
SCI STATUS 1
(WRITE ONLY)
SCCR2
DIRECTION (OUT)
FORCE PIN
SCI CONTROL 2
AND CONTROL
PIN BUFFER
DDD1
INTERNAL
DATA BUS
MC68HC11F1/FC0
MC68HC11FTS/D
PD1
TxD