MC68HC11A1 MOTOROLA [Motorola, Inc], MC68HC11A1 Datasheet - Page 23

• Manufacturer Part Number: MC68HC11A1
• Description: 8-Bit Microcontrollers
• Manufacturer: MOTOROLA [Motorola, Inc]

6 Serial Communications Interface (SCI)
MC68HC11A8
MC68HC11A8TS/D
TRANSMITTER
The SCI, a universal asynchronous receiver transmitter (UART) serial communications interface, is one
of two independent serial I/O subsystems in the MC68HC11A8. It has a standard NRZ format (one start,
eight or nine data, and one stop bit) and several baud rates available. The SCI transmitter and receiver
are independent, but use the same data format and bit rate.
REQUESTS
BAUD RATE
SCI Rx
CLOCK
SCCR1 SCI CONTROL 1
SCI INTERRUPT
REQUEST
H (8) 7 6 5 4 3 2 1 0 L
10 (11) - BIT Tx SHIFT REGISTER
SCDR Tx BUFFER
Figure 6 SCI Transmitter Block Diagram
TDRE
TIE
TC
TCIE
CONTROL LOGIC
TRANSMITTER
SCSR INTERRUPT STATUS
(WRITE ONLY)
SCCR2 SCI CONTROL 2
DIRECTION (OUT)
FORCE PIN
8
AND CONTROL
PIN BUFFER
8
DDD1
INTERNAL
DATA BUS
8
MOTOROLA
11 SCI TX BLOCK
PD1
TxD
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