MC68306FC16 Datasheet, PDF (113/191 Pages) Motorola, Inc – Integrated EC000 Processor

ADDRESS BUS
INTERFACE
TO CPU
CONTROL
DATA
D7–D0
INTERNAL
CONTROL
LOGIC
TIRQ
IRQ
BAUD RATE
X1/CLK
GENERATOR
LOGIC
X2
S
E
R
I
A
L
CHANNEL A
M
FOUR-CHARACTER
RxDA
O
RECEIVE BUFFER
D
U
L
TWO-CHARACTER
TRANSMIT BUFFER
TxDA
E
I
N
16-BIT
T
..C. OUNTER/TIMER
E
R
N
A
INPUT PORT
L
B
U
OUTPUT PORT
S
CHANNEL B
FOUR-CHARACTER
RECEIVE BUFFER
TWO-CHARACTER
TRANSMIT BUFFER
RxDB
TxDB
Figure 6-2. External and Internal Interface Signals
6.2.4 Channel A Receiver Serial Data Input (RxDA)
This signal is the receiver serial data input for channel A. Data received on this signal is
sampled on the rising edge of the clock source, with the least significant bit received first.
6.2.5 Channel B Transmitter Serial Data Output (TxDB)
This signal is the transmitter serial data output for channel B. The output is held high
('mark' condition) when the transmitter is disabled, idle, or operating in the local loopback
mode. Data is shifted out on this signal at the falling edge of the clock source, with the
least significant bit transmitted first.
MOTOROLA
MC68306 USER'S MANUAL
6-5