Typewriter User Manual

MOTOROLA MC68340 USER’S MANUAL 7- 9
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CHANNEL A
CHANNEL B
TRANSMIT
BUFFER (TBA)
(2 REGISTERS)
RECEIVER HOLDING REGISTER 1
RECEIVER HOLDING REGISTER 2
RECEIVER HOLDING REGISTER 3
RECEIVER SHIFT REGISTER
TxDA
RxDA
FIFO
TRANSMIT HOLDING REGISTER
TRANSMIT SHIFT REGISTER
RECEIVE
BUFFER (RBA)
(4 REGISTERS)
W
R
COMMAND REGISTER (CRA)
MODE REGISTER A (MR1A)
MODE REGISTER B (MR2A)
STATUS REGISTER (SRA)
W
R/W
R/W
R
EXTERNAL
INTERFACE
RECEIVER HOLDING REGISTER 1
RECEIVER HOLDING REGISTER 2
RECEIVER HOLDING REGISTER 3
RECEIVER SHIFT REGISTER
TxDB
RxDB
FIFO
TRANSMIT HOLDING REGISTER
TRANSMIT SHIFT REGISTER
RECEIVE
BUFFER (RBB)
(4 REGISTERS)
W
R
COMMAND REGISTER (CRB)
MODE REGISTER 1 (MR1B)
MODE REGISTER 2 (MR2B)
STATUS REGISTER (SRB)
W
R/W
R/W
R
TRANSMIT
BUFFER (TBB)
(2 REGISTERS)
NOTE:
R/W = READ/WRITE
R = READ
W = WRITE
Figure 7-4. Transmitter and Receiver Functional Diagram
Frees
cale Semiconductor,
I
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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