User`s manual
Bit(s)
11-14
(Cont)
15
Designation
Table 3-4 (Cont)
Line Control Register Bit Assignments
(For Asynchronous Line Cards)
Function
Asynchronous Line Card Baud Rate Register (Cont)
Control Strobe
14 13
o 0
o 0
o 0
o 0
o
o
o
o 1
1 0
o
o
o
12
0
0
1
1
0
0
1
1
0
0
1
1
0
0
II
Baud
Rate
0
rn
.)V
1
75
0
110
1
134.5
0
150
1
300
0
600
1 1200
0
1800
1
2000
0 2400
1
3600
0
4800
1 7200
0
9600
38
t
400*
When set
to
a one t strobes the Baud Rate register
bits 11, 12, 13, 14 into storage for the line specified
in
SRS
00-03,
then clears itself.
May
be set at the
same time as the bits that it strobes into storage .
• Speciallnterface Leads For High Speed Operation
Read/Write
Write
DVll
Busy - A response that originates from an asynchronous receiving line
to
indicate that the character servicing rate for
that
line
is
not being sustained. To insure received data integrity, external hardware must interpret and implement this response
in
such a
fashion
to
provide a restraining feature on the remote transmitter. The
"ON"
condition
of
DVII
Busy
is
indicated by a negative voltage
in
the 3
to
IS volt range. The
"OFF"
condition
of
DVII
Busy
~
indicated by a positive voltage in the 3
to
IS volt range.
DV
II
Busy
is
in the
off
state following a Unibus Initialize,
DV
II
Master Clear, or Receiver Enable cleared (LCR Primary Register bit 13). The ON
duration
of
this lead
is
dependent on the servicing rate
of
the
DVII
Character Processor. Therefore,
DVII
Busy
may be
of
any minimal
period.
DVII
Busy
is
asserted a maximum
of
10/16th
of
a bit time following reception of the first stop bit. For an operating speed
of
38,400 baud, the
DVII
Busy feature
must
be used.
Data
Set Busy - The capability
of
an asynchronous transmitting line
to
have continual transmission remotely started and stopped.
This
is
the complementary feature
of
DVII
Busy. Data Set Busy must be implemented with external supporting hardware and must
be used with an operating speed
of
38,400 baud. Line card modification
~
required for implementing Data Set Busy
at
a baud rate
other than 38,400 baud. The
''ON''
condition
of
Data Set
Busy
~
interpreted by a negative voltage
in
the 3
to
15
volt range. The
"OFF"
condition
of
Data Set
Busy
~
interpreted by a positive voltage
in
the 3 to IS volt range. Data Set Busy, when on,
is
defined as
a remote stop request. To inhibit continual character transmission, Data
Set Busy must be received prior to IS/16th
of
the last stop
bit interval. Data
Set
Busy
is
invalid when the line
is
being operated
in
either internal maintenance mode or
at
an operating speed less
than 38,400 baud, assuming no line card modification was performed.
3-19