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CLKTB2 (Clock Shift Register Pulse)
Generated on LSI chip ME16 pin 36. This active high pulse is gen-
erated by any of the following three conditions:
1. During a prime condition, to load the du-my character into
memory - At the end of the PRIME interval, Recirculate signal
SRCL goes high and a single CLKTB2 pulse is generated. This
forces a single ONE into bit 8 of that shift register location,
forming the dummy character.
2.
During character printing, to shift the characters out of memory -
Each STROBE pulse occurring during Strobe Counter interval DCWO
(internal to LSI chip MEI6) generates a CLKTB2 pulse. This shifts
the next character to the output of the shift register where it
remains until the next STROBE DCWO interval.
3. During the interval following the reception of a carriage
return code - A low DSCR input to the chip ANDed with TB8 to
allow each 02* clock to generate a CLKTB2 pulse.
CIPX
(Forward Clutch)
Generated on LSI chip ME16 pin 30. This active low output is used
to turn on the forward clutch when the printer is ready to print the received
line of data.
Signal C!PX goes low when the internal CIPF latch is set.
CIPF gets
set under the following conditions:
(1) the printer is not being primed
(PRIME),
(2) the right limit switch is not activated (EOPSW),
(3) a control
character is not detected at the memory output (TB6 or TB7),
(4) the left
limit switch is activated (RTPSW), and
(5) the dummy character is detected
at the memory output (TB8). The internal CIPF latch then remains set either
until the right limit switch is reached (EOPSW) or a control character appears
at the memory output (TB6.TB7).
Normally, this control character would be a
carriage return code (octal 015).
However, if the DSC option is used (jumper
EI0 to Ell), the control character could be a carriage return (015), line
feed (012), vertical tab (013), or form feed (014) code.
*02 is a phase clock internal to LSI chip MEI6. The frequency of this 02
clock is the same as the OSC output from LSI MEI6.
4-43
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