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Flash, Inhibit, and End of Data (EOD) |
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|  MIL-D-81347C(AS)
register with the contents of the margin register, decrement the vertical position register, delay for
16 microseconds to allow for settling, and then process the next character. An End of Message code
will reset the MPD Logic from the Type mode. Whenever the horizontal or vertical position registers
reach maximum deflection, further position incrementing shall be inhibited until receipt of a Carriage
Return or End of Message code.
Following the presentation of the first character at the X
and Y position of the Set Position Word, each succeeding character shall be presented approximately
1/6 of an inch to the right. The Carriage Return character shall cause the immediately succeeding
character to be presented approximately 1/5 of an inch below the first character of the preceding row
of characters. The horizontal spacing shall be selectable by means of an appropriate switch from
6/512 of the useful tube diameter to 8/512 of the diameter. Similarly, the vertical spacing shall be
selectable by means of a switch from either 8/512 of the useful diameter to 12/512 of the diameter.
The End of Message shall command the Logic to terminate the Type sequence. The sequence of words
from the Set Position Word containing Control Field Code 06 to present the type series ABCD, EFGH
in two rows shall be as shown in Figure 107. The characters are selected from Figure 102, a modifi-
cation of Figure 96, as explained in the preceding sentences. The presentation of the above sequence
of words is illustrated in Figure 108 where the expanded character spacings of 8/512 horizontally and
12/51 2 vertically are shown.
(7) Short Type - Timing for the Short Type operation shall be
identical to that of .3.5.3.4.1.5.3 (6) except that an automatic End of Message shall be performed after
the fifth character. If End of Message or Carriage Return codes are present in any of the five charac-
ter locations, they shall be executed as described in 3.5.3.4.1.5.3(6).
(8) Flash, Inhibit, and End of Data (EOD) - The Flash, Inhibit,
and End of Data bits serve to modify operation as follows: Whenever the flash bit is programmed in a
Plot word, the plot character blinks at a one Hz rate. When the flash bit is programmed in a Set
Position Type (or Short Type) word, the first character in the Typewriter mode blinks. Whenever an
Inhibit bit is programmed in a one-word operation such as Plot or Set Position Analog, the MPD Logic
will reject that word and request another immediately. When an inhibit bit is programmed for a
multiword operation, not only is the Inhibited word rejected, but all subsequent related words are
rejected. Whenever a Set Position (EOD) word is programmed, the MPD Logic will stop and wait for
the next 40 Hz Sync pulse to send a request for computer data. Whenever a 40 Hz Sync pulse occurs,
the MPD Logic tests for the prior receipt of an (EOD) function command if information other than raw
radar video was displayed in the previous cycle. When display operations are synchronized with the
57.1 Hz Sync pulse, no check for an EOD is made. The absence of an End of Data word will enable an
alarm (energize an Overflow lamp at the MPD). If an EOD command is received in the cycle immedi-
ately after the alarm occurs, operation at a 20 Hz rate continues. If no EOD occurs during either the
first or second cycle, then the MPD Logic will generate its own reset upon receipt of the second 40 Hz
Sync pulse.
(9) Conic - If the previous Set Position word specified a conic,
.
the MPD Logic shall store this command, route the next two computer words to the Function Generator
and open analog channel 4 in the MPD. It must accept a reset signal from the Function Generator. It
will close the analog channel and reset from the Conic mode upon sensing the end of the reset signal
from the Function Generator. A description of the operation of the Function Generator is given in
3.5.3.4.3.
(10) Non- operational Modes - Upon receipt of a Function Code
00 or 11 (binary) or Control Field Codes 14 through 77 (octal) the MPD Logic shall perform no display
operation but shall request a new computer word.
Test Mode Operations - The test modes are controlled by an
3.5.3.4.1.5.4
Matrix Test Alignment Test, Vector Test, Type Test
internal test pattern generator, and consist of:
and Conic Test. Data for the patterns is derived through gating from a counter which is synchronized
with the 40 Hz line. The data is re-loaded into the input register through a Request Acknowledge
scheme equivalent to On-Line operation. Operation in the test mode is as follows:
(1) Matrix Test - The Matrix Test uses a series of 64 Plot
commands to achieve the pattern shown in Figure 109. The X and Y axes of the display are shown
173
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