Radio Shack 26-3801 - Page 57

S3
Symbol
TBRE
TBRL
TRE
TRO
TBR1
TBR2
TBR3
TBR4
TBR5
TBR6
TBR7
TBR8
CRL
PI
SBS
Description
A high level
on
TRANSMITTER
BUFFER
REGISTER
EMPTY
indicates
the
transmitter buffer
register
has transferred
its
data
to the
transmitter
register and
is ready for new
data.
A low
level
on
TRANSMITTER BUFFER
REGISTER
LOAD
transfers
data
from inputs
TBR1-TBR8 into
the
transmitter
buffer
register.
A
low
to high
transition on TBRL
indicates
data
transfer to
the transmitter
register
is busy, transfer
is auto-
matically delayed
so
that
the
two
characters
are
transmitted
end
to end.
A high level
on
TRANSMITTER
REGISTER EMPTY
indicates
completed
transmission of a
character including
stop
bits.
Character
data,
start data and
stop bits appear
serially at the
TRANSMITTER
REGISTER
OUTPUT.
Character
data
is loaded into the
TRANSMITTER
BUFFER
REGISTER
via
inputs
TBR1-TBR8.. For character
formats
less
than
8
bits
the
TBR8, 7 and
6
inputs are
ignored
correspond-
ing
to the
programmed
word length.
See Pin
26
-
TBR1
See
Pin 26
-
TBR1
SeePin26-TBRl
See Pin
26
-
TBR1
See
Pin 26
-
TBR1
See
Pin
26 -TBR1
See Pin
26
-
TBR1
A high
level
on CONTROL REGISTER LOAD loads the
control
register.
A high
level
on PARITY INHIBIT inhibits parity generation.
Parity
checking
and forces PE output low.
A
high level
on
STOP BIT SELECT
selects 1.5
stop
bits
for
5
character
format
and 2 stop bits for
other lengths.