Radio Shack TRS-80 Service Manual page 58

SIGNAL GLOSSARY
SIGNAL
NAME
LEDSCP
PENOTSEL
PESEL(N)
PMSOLfN)
PWPPRM(N)
RTP
SELNOTPE
SELRET(N)
STB(N)
STROUT(N)
TBCONFUN(N)
TEBUSY(N)
DESCRIPTION
Limits current
to
the LED's
in
the
RTP
switch
and
the
POWER
indicator
on
the
control panel.
Indicates a paper
empty
condition or not PRINT
enabled.
Same
function as
SELNOTPE
but before the
condition
is
latched.
Paper motion
solenoid
—
used
to activate line
feed
solenoid during
a line
feed
operation.
Pulse generated by
turning on power
to
the
printer
and used
to initialize
the
printer electronics.
Ready
to Print
—
indicates that
the left-hand switch
has been
activated by the carriage actuator arm.
Indicates
PRINT enabled and
not out
of paper.
(Inverse
of
PENOTSEL).
Reset
for
the PESEL(N)
latch.
Print
strobe used
to
enable character address
signals out
of
the character generator.
Signal that occurs
between
printed characters
or
spaces used
to
advance
the
memory
address counter
/
The decoded
carriage return control fuction
bit
that gets loaded
into
memory. Used
to reset the
CIP
latch.
A
short pulse on the
trailing
edge
of
BUSY
signal
used
to
generate an
ACK(N) and
reset the
memory
address
to start location.
SOURCE
DESTINATION
J003-9
LED's
in
the
RTP
switch
and
control panel.
ME24-8
J001-12
ME11-4
ME24-12
J003-11
ME24-9
J003-8
J003-1
ME13-10
ME5-1
ME12-11
ME10-2,
5
ME11-10
ME6-13
ME17-4
ME23-3
J003-7
ME24-13
ME4-7
ME19-28
ME7-7
ME14-22
ME12-1
ME22-4
ME5-5
C8
+
R36 ME9-10
B-2