Tektronix 4010 Maintenance Manual page 115

DRBUSY
AUXSENSE
REV. B, APR. 1976
Master reset for all logic. Origin in
Keyboard (Reset key) and TC-'
when power is initialized.
Used to load data into the
Y or X Data Latches and
(LOXE) to draw vectors.
Originates in TC-'. Asserting a low
on GRAF will set Graphic Plot
Mode.
Su ppresses Linear Interpolation
vector drawing and timing circuitry
on TC-' and TC-2. Asserted by
TC-' when in Alpha Mode.
If not during an ERASE cycle:
Asserted by the Hard Copy Unit
to set up the display for hard
copy readout.
DRBUSY should be asserted
before the trailing edge of
MAKE COPY in order to hold
the Terminal in BUSY during
the scan.
If during an ERASE cycle:
Asserted by the display for the
duration of the erase cycle,
during which information may
not be written on the screen.
Indicates that the Hard Copy Unit
is capable of accepting a MAKE
COPY request.
Status bit line reserved for auxiliary
device(s). Note that HCU may also
be used by aux device(s) if no Hard
Copy Unit is connected and
powered up. Disables Graphic
Lookahead. (Graphic Lookahead is
the ability of TC-1 and TC-2 to
pre·load the Graphic data bytes,
HIY, LOY, and HIX while the
current vector is being drawn.
Receipt of the LOXE Byte is de-
layed until the current vector
drawing is completed.)
FPAUSE
LOCAL
SEND 8
SWITCH'
SWITCH 2
INQUIRE
CURSE
Circuit Description-4010 Maintenance
When originating in TC-2, indicates
that the cross-hair cursor is on or
that coordinate information is
being transm itted to the computer.
Disables the Alpha Cursor, Top of
Page, Margin Shifter, and CR/LF
circuits. Sets Echoplex Suppression.
Asserted by TC-' or options when
entering Graphic Plot Mode in
order to insure that the Character
Generator is disabled.
Indicates that the X Register has
folded over in the process of nor-
mal counting. Will go active with
CR, FF, ETB (control characters),
or RESET (HOME signal). Used to
generate the pause required for
proper operation of the Auto Line-
feed circuit when used with a
clocked interface. (Also used inter-
nally on TC-2 in Graphic Input
Mode.)
Directs input sources to assert
TSTROBE as well as CSTROBE
when sending data to the computer
to provide a local copy on the
screen of data entered into the
computer.
Directs input sources to assert
TSTROBE providing screen display
in the absence of computer echo.
The Interface(s) may also use this
line. Originates in Keyboard switch.
Directs the Interface to accept full
8-bit binary data instead of pro-
viding its own data for the 8th bit.
(The Keyboard does not provide an
8th bit of data.)
}
Asserted
by
Keyboard
switches SW1 and SW2.
Their use is dependent
upon program.
Causes the display to defocus the
writing beam. Active during Alpha
Mode.
Set active when the ENQ Control
Character is preceded by ESC. Sent
by computer when requesting Ter-
minal status.
Set active when the SUB Control
Character is preceded by ESC;
Initiates Graphic Input Mode.
6-3