Data Sheet
April 1997
T7121 HDLC Interface for ISDN (HIFI-64)
Functional Description (continued)
TLBIT = 1 (TRANSMIT LSB FIRST)
DIRECTION OF TRANSMISSION
MSB
BIT 7
LSB
BIT 0
MSB
BIT 7
LSB
BIT 0
TIME-SLOT DATA
A B C D E F G H
a b c d e f g h
HDLC
A B C D E F G H
TRANSMITTER HDLC
PROCESSES LSB FIRST
FIRST BIT
TRANSMITTED
TRANSMIT FIFO
MSB
BIT 7
LSB
BIT 0
LSB
BIT 0
MSB
BIT 7
TIME-SLOT DATA
H G F E D C B A
a b c d e f g h
HDLC
H G F E D C B A
RECEIVER HDLC
EXPECTS LSB FIRST
FIRST BIT
RECEIVED
RECEIVE FIFO
DIRECTION OF RECEPTION
RLBIT = 1 (RECEIVE LSB FIRST)
5-5032
Note: abcdefgh are not the same as ABCDEFGH due to HDLC processing.
Figure 6.Transmission and Reception of Data LSB First
TLBIT = 0 (TRANSMIT MSB FIRST)
DIRECTION OF TRANSMISSION
MSB
BIT 7
LSB
BIT 0
MSB
BIT 7
LSB
BIT 0
TIME-SLOT DATA
H G F E D C B A
a b c d e f g h
HDLC
A B C D E F G H
TRANSMITTER HDLC
PROCESSES LSB FIRST
FIRST BIT
TRANSMITTED
TRANSMIT FIFO
MSB
BIT 7
LSB
BIT 0
LSB
BIT 0
MSB
BIT 7
TIME-SLOT DATA
A B C D E F G H
a b c d e f g h
HDLC
H G F E D C B A
RECEIVER HDLC
EXPECTS LSB FIRST
FIRST BIT
RECEIVED
RECEIVE FIFO
DIRECTION OF RECEPTION
RLBIT = 0 (RECEIVE MSB FIRST)
5-5033
Note: abcdefgh are not the same as ABCDEFGH due to HDLC processing.
Figure 7.Transmission and Reception of Data MSB First
Lucent Technologies Inc.
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